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Management of Helicobacter pylori infection: Guidelines of the Italian Society of Gastroenterology (SIGE) and the Italian Society of Digestive Endoscopy (SIED)

      Abstract

      Helicobacter pylori infection is very common and affects more than one-third of adults in Italy. Helicobacter pylori causes several gastro-duodenal diseases, such as gastritis, peptic ulcer and gastric malignancy, and extra-gastric diseases. The eradication of the bacteria is becoming complex to achieve due to increasing antimicrobial resistance. To address clinical questions related to the diagnosis and treatment of Helicobacter pylori infection, three working groups examined the following topics: (1) non-invasive and invasive diagnostic tests, (2) first-line treatment, and (3) rescue therapies for Helicobacter pylori infection. Recommendations are based on the best available evidence to help physicians manage Helicobacter pylori infection in Italy, and have been endorsed by the Italian Society of Gastroenterology and the Italian Society of Digestive Endoscopy.

      Keywords

      1. Introduction

      Helicobacter (H.) pylori infection is a widespread disease with more than one-third of adults infected in Italy [
      • Hooi J.K.Y.
      • Lai W.Y.
      • Ng W.K.
      • et al.
      Global Prevalence of Helicobacter pylori infection: systematic review and meta-analysis.
      ]. H. pylori may cause chronic gastritis, peptic ulcer disease, gastric adenocarcinoma, or MALT-lymphoma. Therefore, it is important to obtain the diagnosis of infection in the appropriate clinical setting, and once the diagnosis has been achieved, eradication is mandatory. National recommendations on the management of H. pylori infection are thus needed to allow gastroenterologists and general practitioners to have similar evidence-based approach.
      While the diagnosis of H. pylori infection is based on well-established tests, there is still some debate as to when it is more appropriate to search for the infection. On the other side, due to the increase of H. pylori strains resistant to antimicrobials generally used for treating the infection, eradication of the bacterium is becoming more and more complex, involving an increasing number of antimicrobials, with a reduction in the compliance to the therapy and a higher rate of adverse events related to the treatment. Antimicrobial resistance, in particular to clarithromycin and fluoroquinolones, may be vary between different countries and, even in the same country, a regional variability may be present. Therefore, guidelines which may be appropriate for one country, may not be adequate for another. It is very important to adapt recommendations to the needs of the various geographical areas which strictly depend upon the different rates of clarithromycin, fluoroquinolones, metronidazole, or dual (i.e., clarithromycin and metronidazole) antibiotic resistance [
      • Zagari R.M.
      • Rabitti S.
      • Eusebi L.H.
      • et al.
      Treatment of Helicobacter pylori infection: a clinical practice update.
      ]. Based on this, under the auspices of the Italian Society of Gastroenterology (SIGE) and together with the Italian Society of Gastrointestinal Endoscopy (SIED), a group of experts has issued this consensus to support clinical practice guidelines for general practitioners and gastroenterologists who deal with patients with H. pylori infection.

      2. Methods

      This position paper is endorsed by the Italian Society of Gastroenterology and the Italian Society of Digestive Endoscopy. Representatives from SIGE (Marco Romano, Antonietta Gerarda Gravina, Raffaele Pellegrino and Giovanna Palladino) and SIED (Rocco Maurizio Zagari and Leonardo Henry Eusebi), members of the SIGE and SIED National Committee, as well as Antonio Gasbarrini and Francesco Di Mario as external reviewers, participated to the Consensus process. They agreed on a set of key questions to be addressed and on preliminary statements to guide literature research. The following topics were examined: (1) when to search for H. pylori infection, (2) how to search for H. pylori infection, (3) first-line treatment of H. pylori infection, (4) how to deal with H. pylori eradication after the failure of first-line therapy or multiple unsuccessful eradication attempts. The panel performed a systematic search of the literature, reviewed statements based on the best available evidence, and reported graded statements and recommendations. The working group produced statements reporting the quality of available evidence and the strength of the recommendation, graded according to the GRADE system [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ,
      • Balshem H.
      • Helfand M.
      • Schünemann H.J.
      • et al.
      GRADE guidelines: 3. Rating the quality of evidence.
      .
      The databases queried for the data search were MEDLINE, EMBASE, and Web of science. The search was not restricted by specific chronological filters, and the terms for the literature search were selected so that they were functional for the topic sought. Researchers prioritized data from systematic reviews and meta-analyses of randomized controlled trials (RCTs) when available, or individual RCTs with narrow 95% confidence intervals (CIs). If the clinical question was related to a specific population, the selection of studies was limited with filters to the target population to identify evidence related to that specific subgroup.
      The clinical applicability of the statements and recommendations and their implementation in primary care were also considered. Both data from European publications, representative of an epidemiological situation similar to the Italian one, and, of course, from studies carried out in Italy were considered. The statements and recommendations with the supporting evidence were edited and discussed in a 1-day telematic plenary session. After an in-depth discussion, all participants were asked to vote on their agreement with the statements based on the available evidence as well as on the balance between benefits and risks of the same, and the consensus was defined according to the GRADE method. The final document was then submitted for external review to improve the quality of the guidelines, both in terms of expositional quality but also in terms of applicability, feasibility and strength of evidence of the recommendations.
      To assess the strength of the recommendations, the following assessment was used: strong (desirable effects outweigh undesirable effects) or conditional (trade-offs are less certain). In addition, to evaluate the quality of evidence, the following definitions were used: strong (further research is unlikely to change confidence in the estimate), moderate (further research is likely to change confidence in the estimate), low (further research is very likely to change confidence in the estimate), or very low (the estimate of the effect is very uncertain).

      3. Statements

      3.1 Diagnosis

      3.1.1 When to search for H. pylori infection?

      Statement 1: H. pylori should be searched for and eradicated in patients with uninvestigated dyspepsia, in patients younger than 50 years of age, without alarm symptoms.
      Evidence level: moderate; Grade of recommendation: strong
      Dyspepsia is a condition characterized by chronic symptoms, including epigastric pain, burning, early satiety, and postprandial fullness, localized in the central upper quadrant of the abdomen. It is well established that dyspeptic patients of 50 years of age or less without alarm symptoms (i.e., unintentional weight loss, iron-deficiency anemia, gastrointestinal bleeding, dysphagia) should not undergo esophagogastroduodenoscopy (EGDS) and should be non-invasively tested and eventually treated for H. pylori infection [
      • Eusebi L.H.
      • Black C.J.
      • Howden C.W.
      • et al.
      Effectiveness of management strategies for uninvestigated dyspepsia: systematic review and network meta-analysis.
      ]. This approach is supported by several studies as reported by European and American guidelines [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ,
      • Moayyedi P.
      • Lacy B.E.
      • Andrews C.N.
      • et al.
      ACG and CAG clinical guideline: management of dyspepsia.
      . Furthermore, this strategy has been demonstrated to be also cost-effective [
      • Beresniak A.
      • Malfertheiner P.
      • Franceschi F.
      • et al.
      Helicobacter pylori “Test-and-Treat” strategy with urea breath test: a cost-effective strategy for the management of dyspepsia and the prevention of ulcer and gastric cancer in Spain-Results of the Hp-Breath initiative.
      ].
      Statement 2: H. pylori should be searched for and eradicated in patients taking non-steroidal anti-inflammatory drugs (NSAIDs) or acetylsalicylic acid (ASA) with a history of peptic ulcer. The eradication is more beneficial before starting NSAIDs or ASA therapy in preventing complicated and uncomplicated gastroduodenal peptic ulcers.
      Evidence level: moderate; Grade of recommendation: strong
      The use of either NSAIDs or ASA increases the risk of uncomplicated gastroduodenal ulcers and bleeding in patients with H. pylori infection [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ]. The presence of several factors such as anticoagulant use, advanced age, and history of peptic ulcer, further increases the risk [
      • Melcarne L.
      • García-Iglesias P.
      • Calvet X.
      Management of NSAID-associated peptic ulcer disease.
      ,
      • Fashner J.
      • Gitu A.C.
      Diagnosis and treatment of peptic ulcer disease and H. pylori infection.
      . NSAIDs, ASA, and H. pylori infection not only are independent risk factors for peptic ulcers [
      • Huang J.Q.
      • Sridhar S.
      • Hunt R.H.
      Role of Helicobacter pylori infection and non-steroidal anti-inflammatory drugs in peptic-ulcer disease: a meta-analysis.
      ] and for bleeding, but also have an additive effect on peptic ulcer bleeding [
      • Sostres C.
      • Carrera-Lasfuentes P.
      • Benito R.
      • et al.
      Peptic ulcer bleeding risk. The role of Helicobacter pylori Infection in NSAID/Low-Dose Aspirin Users.
      ]. The interaction between H. pylori infection and low-dose ASA remains controversial, although H. pylori eradication reduces peptic ulcer bleeding in ASA users [
      • Sostres C.
      • Carrera-Lasfuentes P.
      • Benito R.
      • et al.
      Peptic ulcer bleeding risk. The role of Helicobacter pylori Infection in NSAID/Low-Dose Aspirin Users.
      ]. Therefore, H. pylori should be non-invasively searched for and eradicated in NSAIDs and ASA users with a history of peptic ulcers, according to international guidelines [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ,
      • Moayyedi P.
      • Lacy B.E.
      • Andrews C.N.
      • et al.
      ACG and CAG clinical guideline: management of dyspepsia.
      . H. pylori eradication is more beneficial before starting NSAIDs and ASA therapy [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ].
      Statement 3: H. pylori should be searched for and eradicated in patients with iron or vitamin B12 deficiency anemia, and in patients with idiopathic thrombocytopenia
      Evidence level: very low; Grade of recommendation: weak
      Iron deficiency anemia (IDA) is well known to be associated with H. pylori infection, as demonstrated by several reviews and meta-analyses [
      • Muhsen K.
      • Cohen D.
      Helicobacter pylori infection and iron stores: a systematic review and meta-analysis.
      ,
      • Qu X.-H.
      • Huang X.-L.
      • Xiong P.
      • et al.
      Does Helicobacter pylori infection play a role in iron deficiency anemia? A meta-analysis.
      ,
      • Huang X.
      • Qu X.
      • Yan W.
      • et al.
      Iron deficiency anaemia can be improved after eradication of Helicobacter pylori.
      ,
      • Yuan W.
      • Li Y.
      • Kehu Y.
      • et al.
      Iron deficiency anemia in Helicobacter pylori infection: meta-analysis of randomized controlled trials.
      ,
      • Zhang Z.-F.
      • Yang N.
      • Zhao G.
      • et al.
      Effect of Helicobacter pylori eradication on iron deficiency.
      ,
      • Gravina A.G.
      • Zagari R.M.
      • De Musis C.
      • et al.
      Helicobacter pylori and extragastric diseases: A review.
      ,
      • Gravina A.G.
      • Priadko K.
      • Ciamarra P.
      • et al.
      Extra-gastric manifestations of Helicobacter pylori Infection.
      ].
      Several pathophysiological mechanisms are involved in this association: chronic blood loss due to the presence of gastric erosions or ulcers [
      • Gravina A.G.
      • Priadko K.
      • Ciamarra P.
      • et al.
      Extra-gastric manifestations of Helicobacter pylori Infection.
      ]; iron absorption deficiency at the duodenum due to increased gastric pH in H. pylori-associated corpus-predominant chronic gastritis which may impair the transformation of dietary Fe3+ to Fe2+ [
      • Senkovich O.
      • Ceaser S.
      • McGee D.J.
      • et al.
      Unique host iron utilization mechanisms of Helicobacter pylori revealed with iron-deficient chemically defined media.
      ]; altered expression of hepcidin, a protein that regulates iron absorption by enterocytes, in patients with H. pylori infection [
      • Ozkasap S.
      • Yarali N.
      • Isik P.
      • et al.
      The role of prohepcidin in anemia due to Helicobacter pylori infection.
      ,
      • Mendoza E.
      • Duque X.
      • Hernández Franco J.I.
      • et al.
      Association between Active H. pylori infection and iron deficiency assessed by serum hepcidin levels in school-age children.
      ; the ability of H. pylori to acquire iron from host glycoproteins as transferrin and lactoferrin [
      • Senkovich O.
      • Ceaser S.
      • McGee D.J.
      • et al.
      Unique host iron utilization mechanisms of Helicobacter pylori revealed with iron-deficient chemically defined media.
      ]; the ability of H. pylori to cause up-regulation of TNF-α, a pro-inflammatory cytokine that may cause IDA [
      • Stabler S.P.
      Vitamin B12 deficiency.
      ]. Indeed, eradication of H. pylori infection leads to a reversal of IDA in up to 75% of patients [
      • Hudak L.
      • Jaraisy A.
      • Haj S.
      • et al.
      An updated systematic review and meta-analysis on the association between Helicobacter pylori infection and iron deficiency anemia.
      ].
      H. pylori infection is also associated with low levels of vitamin B12 (Vit. B12) [
      • Stabler S.P.
      Vitamin B12 deficiency.
      ,
      • Lahner E.
      • Persechino S.
      • Annibale B.
      Micronutrients (Other than iron) and Helicobacter pylori infection: a systematic review.
      , thus possibly leading to Vit. B12 deficiency anemia. Low levels of Vit. B12 are associated with an increase in homocysteine, a metabolic product of Vit. B12 [
      • Zagari R.M.
      • Rabitti S.
      • Eusebi L.H.
      • et al.
      Treatment of Helicobacter pylori infection: a clinical practice update.
      ,
      • Lahner E.
      • Persechino S.
      • Annibale B.
      Micronutrients (Other than iron) and Helicobacter pylori infection: a systematic review.
      . Levels of Vit. B12 and homocysteine return to normal values after eradication of H. pylori infection [
      • Lahner E.
      • Persechino S.
      • Annibale B.
      Micronutrients (Other than iron) and Helicobacter pylori infection: a systematic review.
      ,
      • Campuzano-Maya G.
      Hematologic manifestations of Helicobacter pylori infection.
      . The mechanism of H. pylori-induced Vit. B12 deficiency could be related to the failure of gastric parietal cells to produce intrinsic factor in patients with H. pylori-associated corpus-predominant chronic gastritis [
      • Valdes-Socin H.
      • Leclercq P.
      • Polus M.
      • et al.
      [Chronic autoimmune gastritis : a multidisciplinary management].
      ].
      Primary immune thrombocytopenia (ITP) is an autoimmune disorder, linked to H. pylori infection [
      • Valdes-Socin H.
      • Leclercq P.
      • Polus M.
      • et al.
      [Chronic autoimmune gastritis : a multidisciplinary management].
      ]. The putative pathogenic mechanism of this association is a molecular mimicry between platelet surface glycoproteins and amino acid sequences of H. pylori virulence factors, such as H. pylori lipopolysaccharide (LPS), Vac A, CagA, and urease B [
      • Campuzano-Maya G.
      Hematologic manifestations of Helicobacter pylori infection.
      ,
      • Kodama M.
      • Kitadai Y.
      • Ito M.
      • et al.
      Immune response to CagA protein is associated with improved platelet count after Helicobacter pylori eradication in patients with idiopathic thrombocytopenic purpura.
      . Also, H. pylori up-regulates Fcγ receptor expression, thus increasing the phagocytic capacity and down-regulating inhibitory receptors FcγRIIB that in turn enhance monocyte activity and autoreactivity in B and T lymphocytes [
      • Kodama M.
      • Kitadai Y.
      • Ito M.
      • et al.
      Immune response to CagA protein is associated with improved platelet count after Helicobacter pylori eradication in patients with idiopathic thrombocytopenic purpura.
      ,
      • Asahi A.
      • Nishimoto T.
      • Okazaki Y.
      • et al.
      Helicobacter pylori eradication shifts monocyte Fcgamma receptor balance toward inhibitory FcgammaRIIB in immune thrombocytopenic purpura patients.
      ,
      • Testerman T.L.
      • Morris J.
      Beyond the stomach: an updated view of Helicobacter pylori pathogenesis, diagnosis, and treatment.
      ,
      • Satoh T.
      • Pandey J.P.
      • Okazaki Y.
      • et al.
      Single nucleotide polymorphism of interleukin-1beta associated with Helicobacter pylori infection in immune thrombocytopenic purpura.
      ]. As a result, B-lymphocytes produce autoantibodies against circulating platelets [
      • Campuzano-Maya G.
      Hematologic manifestations of Helicobacter pylori infection.
      ,
      • Asahi A.
      • Nishimoto T.
      • Okazaki Y.
      • et al.
      Helicobacter pylori eradication shifts monocyte Fcgamma receptor balance toward inhibitory FcgammaRIIB in immune thrombocytopenic purpura patients.
      ,
      • Testerman T.L.
      • Morris J.
      Beyond the stomach: an updated view of Helicobacter pylori pathogenesis, diagnosis, and treatment.
      ,
      • Satoh T.
      • Pandey J.P.
      • Okazaki Y.
      • et al.
      Single nucleotide polymorphism of interleukin-1beta associated with Helicobacter pylori infection in immune thrombocytopenic purpura.
      ]. The potential causative role of H. pylori is suggested by many studies, showing that successful H. pylori eradication leads to a rise of the platelet count [
      • Suvajdzić N.
      • Stanković B.
      • Artiko V.
      • et al.
      Helicobacter pylori eradication can induce platelet recovery in chronic idiopathic thrombocytopenic purpura.
      ,
      • Jackson S.C.
      • Beck P.
      • Buret A.G.
      • et al.
      Long term platelet responses to Helicobacter pylori eradication in Canadian patients with immune thrombocytopenic purpura.
      . IDA, Vit. B12 deficiency and ITP are the only extra-gastric disorders associated with H. pylori infection for which the European Guidelines recommend searching for and eradicating H. pylori infection in a non-invasive manner [
      • Zagari R.M.
      • Rabitti S.
      • Eusebi L.H.
      • et al.
      Treatment of Helicobacter pylori infection: a clinical practice update.
      ]. H. pylori infection has been associated with other extra-gastric conditions, such as neurologic diseases (i.e. Alzheimer's disease, Multiple sclerosis, Parkinson's disease, Guillain-Barrè syndrome), ocular diseases (i.e. open-angle glaucoma, central serous chorioretinitis, blepharitis), metabolic diseases (i.e. diabetes mellitus, insulin resistance syndrome, metabolic syndrome), cardiovascular diseases (i.e. coronary atherosclerotic disease, myocardial infarction), dermatologic diseases (i.e. rosacea, psoriasis, chronic urticarial, alopecia areata, autoimmune bullous disease, Schoenlein-Henoch purpura). However, the causality of most of these associations has not been proven [
      • Gravina A.G.
      • Zagari R.M.
      • De Musis C.
      • et al.
      Helicobacter pylori and extragastric diseases: A review.
      ,
      • Gravina A.G.
      • Priadko K.
      • Ciamarra P.
      • et al.
      Extra-gastric manifestations of Helicobacter pylori Infection.
      , and although a clinical improvement following H. pylori eradication has been shown in many studies, to date we do not have enough strong evidence to suggest testing for and treating H. pylori for extra-gastric diseases, except for the aforementioned hematological manifestations [
      • Gravina A.G.
      • Zagari R.M.
      • De Musis C.
      • et al.
      Helicobacter pylori and extragastric diseases: A review.
      ,
      • Gravina A.G.
      • Priadko K.
      • Ciamarra P.
      • et al.
      Extra-gastric manifestations of Helicobacter pylori Infection.
      .
      Statement 4: In patients with gastroesophageal reflux disease (GERD) on PPI therapy, eradication of H. pylori is recommended.
      Evidence level: low; Grade of recommendation: weak
      Several studies have suggested a protective role of H. pylori against GERD and its complications through a reduction in gastric acid secretion [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ,
      • Warburton-Timms V.J.
      • Charlett A.
      • Valori R.M.
      • et al.
      The significance of cagA(+) Helicobacter pylori in reflux oesophagitis.
      ,
      • Zamani M.
      • Alizadeh-Tabari S.
      • Hasanpour A.H.
      • et al.
      Systematic review with meta-analysis: association of Helicobacter pylori infection with gastro-oesophageal reflux and its complications.
      ,
      • Rokkas T.
      • Pistiolas D.
      • Sechopoulos P.
      • et al.
      Relationship between Helicobacter pylori infection and esophageal neoplasia: a meta-analysis.
      ]. Eradication of the bacterium does not appear to be associated with worsening of preexisting GERD nor does it alter the response to proton pump inhibitors. Therefore, the change in gastric acid secretion after eradication of H. pylori infection should not be used as a decisive argument for treating or not treating the infection [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ,
      • Laine L.
      • Sugg J.
      Effect of Helicobacter pylori eradication on development of erosive esophagitis and gastroesophageal reflux disease symptoms: a post hoc analysis of eight double blind prospective studies.
      ,
      • Yaghoobi M.
      • Farrokhyar F.
      • Yuan Y.
      • et al.
      Is there an increased risk of GERD after Helicobacter pylori eradication?: a meta-analysis.
      ,
      • Qian B.
      • Ma S.
      • Shang L.
      • et al.
      Effects of Helicobacter pylori eradication on gastroesophageal reflux disease.
      ,
      • Moayyedi P.
      • Bardhan C.
      • Young L.
      • et al.
      Helicobacter pylori eradication does not exacerbate reflux symptoms in gastroesophageal reflux disease.
      ]. However, long-term treatment with proton pump inhibitors (PPIs), used for chronic GERD, in infected individuals has been shown to facilitate the migration of the bacterium from the antrum to the gastric body, leading to the development of body gastritis that is more associated with the development of gastric cancer [
      • Kuipers E.J.
      • Uyterlinde A.M.
      • Peña A.S.
      • et al.
      Increase of Helicobacter pylori-associated corpus gastritis during acid suppressive therapy: implications for long-term safety.
      ,
      • Kuipers E.J.
      • Lundell L.
      • Klinkenberg-Knol E.C.
      • et al.
      Atrophic gastritis and Helicobacter pylori infection in patients with reflux esophagitis treated with omeprazole or fundoplication.
      ,
      • García Rodríguez L.A.
      • Lagergren J.
      • Lindblad M.
      Gastric acid suppression and risk of oesophageal and gastric adenocarcinoma: a nested case control study in the UK.
      ,
      • Mukaisho K.
      • Hagiwara T.
      • Nakayama T.
      • et al.
      Potential mechanism of corpus-predominant gastritis after PPI therapy in Helicobacter pylori-positive patients with GERD.
      ].
      The prevalence of H. pylori infection in family members or sexual partners of H. pylori-infected individuals has not been widely studied. A recent prospective study described a 74.5% prevalence of H. pylori infection in sexual partners of H. pylori-infected individuals compared with 32.3% in the control group [
      • Sgambato D.
      • Visciola G.
      • Ferrante E.
      • et al.
      Prevalence of Helicobacter pylori infection in sexual partners of H. pylori-infected subjects: Role of gastroesophageal reflux.
      ]. The risk of both partners being infected was higher in those who had lived together for a long period and in couples with at least one member with GERD. However, major international guidelines do not recommend testing family contacts or sexual partners of infected individuals for H. pylori infection, and such research could be performed only if the patient explicitly requested it.

      3.1.2 Which tests should be used for the diagnosis of H. pylori infection?

      3.1.2.1 Non-invasive tests

      Statement 5: 13C-urea breath test and monoclonal ELISA stool antigen test have high accuracy for non-invasive diagnosis of H. pylori infection, both in pre- and post-therapy settings.
      Evidence level: high; Grade of recommendation: strong
      The preferred non-invasive diagnostic method for H. pylori infection is the 13C Urea Breath test (13C UBT) which has a sensitivity of 96% and a specificity of 93% [
      • Ferwana M.
      • Abdulmajeed I.
      • Alhajiahmed A.
      • et al.
      Accuracy of urea breath test in Helicobacter pylori infection: meta-analysis.
      ,
      • Kayali S.
      • Aloe R.
      • Bonaguri C.
      • Gaiani F.
      • et al.
      Non-invasive tests for the diagnosis of Helicobacter pylori: state of the art.
      . The ELISA stool antigen test (SAT) that detects H. pylori antigens in the feces, has a diagnostic performance similar to 13C-UBT, with a sensitivity and specificity of 93.3% and 93.2%, respectively [
      • Makristathis A.
      • Hirschl A.M.
      • Mégraud F.
      • et al.
      Review: Diagnosis of Helicobacter pylori infection.
      ,
      • Best L.M.
      • Takwoingi Y.
      • Siddique S.
      • et al.
      Non-invasive diagnostic tests for Helicobacter pylori infection.
      ,
      • Gisbert J.P.
      • de la Morena F.
      • Abraira V.
      Accuracy of monoclonal stool antigen test for the diagnosis of H. pylori infection: a systematic review and meta-analysis.
      ].
      The Rapid monophase HpSA test, based on an immunochromatographic technique, is an alternative to the ELISA SAT for an immediate evaluation of the H. pylori status but is less accurate than the ELISA test, in particular for the evaluation of treatment success after eradication therapy [
      • Calvet X.
      • Lario S.
      • Ramírez-Lázaro M.J.
      • et al.
      Accuracy of monoclonal stool tests for determining cure of Helicobacter pylori infection after treatment.
      ]. None of the stool antigen detecting tests can be performed in patients with diarrhea, nevertheless SATs appear to be an alternative to the UBT in elderly patients, pregnant women, and children, in whom performing a breath test may be troublesome [
      • Gisbert J.P.
      • de la Morena F.
      • Abraira V.
      Accuracy of monoclonal stool antigen test for the diagnosis of H. pylori infection: a systematic review and meta-analysis.
      ,
      • Calvet X.
      • Lario S.
      • Ramírez-Lázaro M.J.
      • et al.
      Accuracy of monoclonal stool tests for determining cure of Helicobacter pylori infection after treatment.
      .
      To minimize the probability of false-negative results, each of the above-mentioned tests should be performed at least 4 weeks after stopping antibiotic or bismuth compounds use, and 2 weeks after proton pump inhibitors (PPIs) suspension [
      • Ferwana M.
      • Abdulmajeed I.
      • Alhajiahmed A.
      • et al.
      Accuracy of urea breath test in Helicobacter pylori infection: meta-analysis.
      ,
      • Best L.M.
      • Takwoingi Y.
      • Siddique S.
      • et al.
      Non-invasive diagnostic tests for Helicobacter pylori infection.
      ,
      • Levine A.
      • Shevah O.
      • Shabat-Sehayek V.
      • et al.
      Masking of 13C urea breath test by proton pump inhibitors is dependent on type of medication: comparison between omeprazole, pantoprazole, lansoprazole and esomeprazole.
      ,
      • Asfeldt A.M.
      • Løchen M.-L.
      • Straume B.
      • et al.
      Accuracy of a monoclonal antibody-based stool antigen test in the diagnosis of Helicobacter pylori infection.
      . Antiacids do not impair UBT and SAT sensitivity [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ], whereas H2-receptor antagonists have only a minimal effect on the sensitivity of 13C-UBT since they do not have an anti-H.pylori activity, differently than PPIs. Bleeding peptic ulcers reduce the sensitivity of both UBT and SAT. Moreover, these non-invasive tests may also have a lower sensitivity in patients with gastric precancerous lesions, gastric cancer, and partial gastrectomy [
      • Sánchez-Delgado J.
      • Gené E.
      • Suárez D.
      • et al.
      Has H. pylori prevalence in bleeding peptic ulcer been underestimated? A meta-regression.
      ].
      Statement 6: Positive IgG serology is an indicator of past infection, but not necessarily of an ongoing infection. Serum IgG antibodies should not be used after eradication treatment.
      Evidence level: moderate; Grade of recommendation: strong
      Serology (i.e., detection of anti-H. pylori IgG) does not discriminate between ongoing versus past infection and, therefore, its use to diagnose H. pylori infection should be discouraged. This test has a high negative predictive value but a low positive predictive value. Serum IgG may however represent the method of choice for diagnosing H. pylori infection in patients with bleeding ulcers, atrophic gastropathy, MALToma, gastric cancer, recent antibiotics, and PPIs use, as well as in cases when it is not possible to stop PPI treatments for at least 2 weeks or antibiotics for 4 weeks before testing [
      • Makristathis A.
      • Hirschl A.M.
      • Mégraud F.
      • et al.
      Review: Diagnosis of Helicobacter pylori infection.
      ,
      • Levine A.
      • Shevah O.
      • Shabat-Sehayek V.
      • et al.
      Masking of 13C urea breath test by proton pump inhibitors is dependent on type of medication: comparison between omeprazole, pantoprazole, lansoprazole and esomeprazole.
      ,
      • Asfeldt A.M.
      • Løchen M.-L.
      • Straume B.
      • et al.
      Accuracy of a monoclonal antibody-based stool antigen test in the diagnosis of Helicobacter pylori infection.
      . The sensitivity and specificity of serum IgG anti-H. pylori test is 85% and 79%, respectively, highest in case of monoclonal antibodies [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ,
      • Kayali S.
      • Aloe R.
      • Bonaguri C.
      • Gaiani F.
      • et al.
      Non-invasive tests for the diagnosis of Helicobacter pylori: state of the art.
      ,
      • Asfeldt A.M.
      • Løchen M.-L.
      • Straume B.
      • et al.
      Accuracy of a monoclonal antibody-based stool antigen test in the diagnosis of Helicobacter pylori infection.
      .
      The detection of CagA antibodies cannot be used as H. pylori diagnostic test [
      • Moayyedi P.
      • Lacy B.E.
      • Andrews C.N.
      • et al.
      ACG and CAG clinical guideline: management of dyspepsia.
      ], but it may be useful for the evaluation of the risk of gastric cancer. In Western countries, the seroprevalence of anti-CagA antibodies is less than 50% in infected individuals.
      Serum IgG should not be used to assess the eradication of H. pylori since the antibodies continue to be detectable for 6-12 months after H. pylori eradication [
      • Zagari R.M.
      • Romano M.
      • Ojetti V.
      • et al.
      Guidelines for the management of Helicobacter pylori infection in Italy: the III Working Group Consensus Report 2015.
      ,
      • Darma A.
      • Nugroho B.S.T.
      • Yoanna V.
      • et al.
      Comparison of Helicobacter pylori stool antigen, salivary IgG, serum IgG, and serum IgM as diagnostic markers of H. pylori infection in children.
      .

      3.1.2.2 Invasive tests

      Statement 7: When there is an indication to perform upper endoscopy with gastric biopsies, histology should be used for the diagnosis of H. pylori infection both pre- and post-eradication treatment. Immunohistochemical analysis should be performed only in rare cases, such as when chronic or atrophic gastritis are present.
      Evidence level: moderate; Grade of recommendation: strong
      Endoscopic tools, such as narrow-band imaging, linked color imaging, and blue laser imaging, do not allow an accurate H. pylori status evaluation, but are recommended by MAPS II guidelines for targeted biopsy sampling that efficiently improves the likelihood of diagnosing precancerous gastric lesions related to H. pylori infection [
      • Pimentel-Nunes P.
      • Libânio D.
      • Marcos-Pinto R.
      • et al.
      Management of epithelial precancerous conditions and lesions in the stomach (MAPS II): European Society of Gastrointestinal Endoscopy (ESGE), European Helicobacter and Microbiota Study Group (EHMSG), European Society of Pathology (ESP), and Sociedade Portuguesa de EndoscopiaDigestiva (SPED) guideline update 2019.
      ]. Histology remains the gold standard for diagnosing H. pylori infection. Hematoxylin and eosin (H&E) staining was found to be 94% accurate compared to complementary staining immunohistochemistry (IHC), whereas the latter is preferred over H&E only in the presence of active chronic gastritis without H. pylori identification by standard staining, mainly due to low bacterial density or atypical localization of the pathogen [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ,
      • Makristathis A.
      • Hirschl A.M.
      • Mégraud F.
      • et al.
      Review: Diagnosis of Helicobacter pylori infection.
      ,
      • Benoit A.
      • Hoyeau N.
      • Fléjou J.-F.
      Diagnosis of Helicobacter pylori infection on gastric biopsies: Standard stain, special stain or immunohistochemistry?.
      . Moreover, IHC could be useful in patients with chronic gastritis in which the suspicion of infection is high, such as in patients with atrophic gastritis when no bacteria are identified by standard histological examination [
      • Pimentel-Nunes P.
      • Libânio D.
      • Marcos-Pinto R.
      • et al.
      Management of epithelial precancerous conditions and lesions in the stomach (MAPS II): European Society of Gastrointestinal Endoscopy (ESGE), European Helicobacter and Microbiota Study Group (EHMSG), European Society of Pathology (ESP), and Sociedade Portuguesa de EndoscopiaDigestiva (SPED) guideline update 2019.
      ]. However, IHC is not available in all laboratories, and it is more expensive than H&E [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ].
      According to the updated Sydney System, biopsies should be taken from the antrum and the corpus (lesser and greater curvature), and from the incisura angularis [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ,
      • Dixon M.F.
      • Genta R.M.
      • Yardley J.H.
      • et al.
      Classification and grading of gastritis. The updated Sydney System. International Workshop on the Histopathology of Gastritis, Houston 1994.
      . In particular, according to MAPS 2 guidelines, 2 biopsies should be taken from the antrum and two from the body of the stomach [
      • Pimentel-Nunes P.
      • Libânio D.
      • Marcos-Pinto R.
      • et al.
      Management of epithelial precancerous conditions and lesions in the stomach (MAPS II): European Society of Gastrointestinal Endoscopy (ESGE), European Helicobacter and Microbiota Study Group (EHMSG), European Society of Pathology (ESP), and Sociedade Portuguesa de EndoscopiaDigestiva (SPED) guideline update 2019.
      ].
      Statement 8: Rapid urease test (RUT) should be performed in patients who undergo an upper endoscopy to prescribe immediately an eradication treatment for those H. pylori-positive. RUT should not be used after eradication treatment as the sensitivity is lower in this setting.
      Evidence level: low; Grade of recommendation: weak
      The rapid urease test (RUT) showed a sensitivity of approximately 90% and specificity of 95-100% [
      • el-Zimaity H.M.
      • al-Assi M.T.
      • Genta R.M.
      • et al.
      Confirmation of successful therapy of Helicobacter pylori infection: number and site of biopsies or a rapid urease test.
      ,
      • Woo J.S.
      • el-Zimaity H.M.
      • Genta R.M.
      • et al.
      The best gastric site for obtaining a positive rapid ureas test.
      . Sensitivity is lower in case of recent gastrointestinal bleeding or in patients recently treated with PPIs, antibiotics, bismuth-containing compounds, or when diffuse atrophy and intestinal metaplasia are present. For RUT, one biopsy from the antrum and one biopsy from the corpus should be taken to minimize false-negative results [
      • Wong A.
      • Ching S.S.
      • Long A.S.
      The use of a second biopsy from the gastric body for the detection of Helicobacter pylori using rapid urease test.
      ]. False-positive tests are unusual but may occur when urease-containing bacteria, such as Proteus mirabilis, Citrobacter freundii, Klebsiella pneumoniae, Enterobacter cloacae, and Staphylococcus aureus, are present in the stomach [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ,
      • Osaki T.
      • Mabe K.
      • Hanawa T.
      • et al.
      Urease-positive bacteria in the stomach induce a false-positive reaction in a urea breath test for diagnosis of Helicobacter pylori infection.
      . RUT can give quick information about H. pylori status and allows to prescribe an eradication therapy immediately [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ].
      Statement 9: The accuracy of molecular methods on gastric biopsies should be better defined.
      Evidence level: very low; Grade of recommendation: weak
      Molecular methods, such as real-time PCR, allow to define the H. pylori status of a patient as well as to evaluate if the clinical isolate carries genes that confer resistance against clarithromycin or levofloxacin, thus allowing a targeted therapy. More studies are needed to evaluate the accuracy of commercially available kits which find a large application in clinical practice [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ]. Interestingly, recent studies on noninvasive molecular analysis of stool specimens for the detection of point mutations in H. pylori DNA, have reported an overall high sensitivity and specificity for clarithromycin and levofloxacin genotypic resistance comparable to that obtained with culture or PCR on gastric biopsies [
      • Ierardi E.
      • Giorgio F.
      • Iannone A.
      • et al.
      Noninvasive molecular analysis of Helicobacter pylori: Is it time for tailored first-line therapy?.
      ,
      • Losurdo G.
      • Giorgio F.
      • Pricci M.
      • et al.
      Helicobacter pylori primary and secondary genotypic resistance to clarithromycin and levofloxacin detection in stools: A 4-Year scenario in Southern Italy.
      .
      Statement 10: Culture cannot be considered a routine diagnostic test, but should be used only after multiple treatment failures to choose the most appropriate therapy.
      Evidence level: very low; Grade of recommendation: weak
      Culture is not currently used to diagnose H. pylori infection as it is complex, costly, and requires dedicated personnel. In addition, H. pylori culture showed poorer sensitivity in patients who underwent previous eradication treatment compared to naïve ones [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ,
      • Zagari R.M.
      • Romano M.
      • Ojetti V.
      • et al.
      Guidelines for the management of Helicobacter pylori infection in Italy: the III Working Group Consensus Report 2015.
      . Thus, culture and in vitro anti-microbial sensitivity testing should be restricted to patients who are resistant to at least two eradication treatments, allowing targeted therapy.

      3.2 Treatment

      3.2.1 Which eradication regimen should be used as first-line therapy in Italy?

      Statement 11: Bismuth-based quadruple therapy, concomitant therapy, or sequential therapy should be used as first-line treatment for H. pylori. A 14-day standard triple therapy may only be considered in areas with proven low clarithromycin resistance (<15%).
      Evidence level: moderate; Grade of recommendation: strong.
      The increasing resistance to antibiotics is the main issue in the treatment of H. pylori infection. There is unanimous consensus that the choice of the first-line therapy should be driven by the local prevalence of clarithromycin resistance; however, this information is often lacking [
      • Zagari R.M.
      • Rabitti S.
      • Eusebi L.H.
      • et al.
      Treatment of Helicobacter pylori infection: a clinical practice update.
      ].
      The antibiotic susceptibility profile of H. pylori in most regions of Italy is unknown; however, there is evidence of a high prevalence, around 30%, of clarithromycin resistance in some areas of the Center and South of Italy [
      • Fiorini G.
      • Zullo A.
      • Saracino I.M.
      • et al.
      Antibiotic resistance pattern of Helicobacter pylori strains isolated in Italy during 2010-2016.
      ]. International guidelines recommend a 10- or 14-day quadruple therapy, the bismuth-based quadruple therapy or the non-bismuth concomitant quadruple therapy, as first-line therapy in countries with high (>15%) or unknown prevalence of clarithromycin resistance. The efficacy of these two regimens is not affected by clarithromycin and metronidazole resistance, and bismuth-based quadruple therapy performs well also against dual clarithromycin and metronidazole resistance.
      The bismuth-based quadruple therapy is a complex 20-year-old regimen including PPI, bismuth, tetracycline, and metronidazole [
      • Losurdo G.
      • Giorgio F.
      • Pricci M.
      • et al.
      Helicobacter pylori primary and secondary genotypic resistance to clarithromycin and levofloxacin detection in stools: A 4-Year scenario in Southern Italy.
      ]. To overcome the complexity of this regimen, a new galenic formulation of the “3-in-1” capsule (Pylera®) is available in many European countries including Italy [
      • Fallone C.A.
      • Chiba N.
      • van Zanten S.V.
      • et al.
      The Toronto Consensus for the Treatment of Helicobacter pylori Infection in Adults.
      ]. In a meta-analysis of 21 studies, Pylera® yielded a pooled intention-to-treat eradication rate of about 90% as first-line therapy [
      • Nyssen O.P.
      • McNicholl A.G.
      • Gisbert J.P.
      Meta-analysis of three-in-one single capsule bismuth-containing quadruple therapy for the eradication of Helicobacter pylori.
      ]. Several studies carried out in Italy have confirmed the high efficacy of Pylera® across different regions, including those with a high prevalence of clarithromycin resistance [
      • Zagari R.M.
      • Romiti A.
      • Ierardi E.
      • et al.
      The “three-in-one” formulation of bismuth quadruple therapy for Helicobacter pylori eradication with or without probiotics supplementation: Efficacy and safety in daily clinical practice.
      ,
      • Tursi A.
      • Franceschi M.
      • Allegretta L.
      • et al.
      Effectiveness and Safety of Pylera® in patients infected by Helicobacter pylori: a multicenter, retrospective, real life study.
      ,
      • Di Ciaula A.
      • Scaccianoce G.
      • Venerito M.
      • et al.
      Eradication rates in Italian subjects heterogeneously managed for Helicobacter pylori infection. Time to abandon empiric treatments in Southern Europe.
      ].
      The concomitant therapy includes PPI, clarithromycin, amoxicillin, and metronidazole or tinidazole, all given together. Although single clarithromycin and metronidazole resistance do not undermine the therapeutic performance of this regimen, the effectiveness of concomitant therapy drops to a suboptimal 75% eradication rate in patients with dual clarithromycin and metronidazole resistance. Thus, this regimen is not recommended in areas with a known high prevalence (>15%) of dual clarithromycin and metronidazole resistance. A recent randomized controlled trial carried out in Italy showed that concomitant therapy was not inferior to bismuth-based quadruple therapy with eradication rates of around 90% as first-line treatment for H. pylori infection [
      • De Francesco V.
      • Pontone S.
      • Bellesia A.
      • et al.
      Quadruple, sequential, and concomitant first-line therapies for H. pylori eradication: a prospective, randomized study.
      ]. Similar results have been reported from another study from an area of Southern Italy with a high prevalence of clarithromycin resistance [
      • Romano M.
      • Gravina A.G.
      • Nardone G.
      • et al.
      Non-bismuth and bismuth quadruple therapies based on previous clarithromycin exposure are as effective and safe in an area of high clarithromycin resistance: A real-life study.
      ]. Therefore, there is consistent evidence that both bismuth-based quadruple therapy and concomitant therapy can be considered good options for the first-line treatment of H. pylori in Italy. Bismuth-based quadruple therapy has the advantage that bismuth is not used against other infectious diseases and that the use of tetracycline is minimal in clinical practice. On the other hand, it has been suggested that with concomitant therapy each patient may receive one unnecessary antibiotic. Thus, bismuth quadruple therapy may be considered the best choice for the empirical first-line treatment of H. pylori in Italy, especially in subjects who have previously received clarithromycin for conditions other than H. pylori infection [
      • Zagari R.M.
      • Romiti A.
      • Ierardi E.
      • et al.
      The “three-in-one” formulation of bismuth quadruple therapy for Helicobacter pylori eradication with or without probiotics supplementation: Efficacy and safety in daily clinical practice.
      ].
      Sequential therapy, which includes PPI plus amoxicillin for 5-7 days followed by PPI plus metronidazole and clarithromycin for another 5-7 days, is a regimen designed to overcome the issue of clarithromycin resistance. However, data on the efficacy of this regimen against clarithromycin-resistant H. pylori strains are contradictory. Two systematic reviews with meta-analysis showed that sequential therapy was not better than 14-day standard triple therapy in the first-line treatment of H. pylori, with pooled eradication rates around 80% for both regimens [
      • Nyssen O.P.
      • McNicholl A.G.
      • Megraud F.
      • et al.
      Sequential versus standard triple first-line therapy for Helicobacter pylori eradication.
      ,
      • Gatta L.
      • Vakil N.
      • Vaira D.
      • et al.
      Global eradication rates for Helicobacter pylori infection: systematic review and meta-analysis of sequential therapy.
      ; in addition, the sub-group analysis that included subjects with clarithromycin-resistant H. pylori strains showed that eradication rate decreased to a sub-optimal 70% with sequential therapy. Based on these data, international guidelines and a review reconciling guidelines have discouraged the use of sequential therapy for the treatment of H. pylori. However, sequential therapy seems to perform well in Italy providing eradication rates of around 90%, also in the presence of clarithromycin resistance. Two randomized controlled trials showed that sequential therapy achieved eradication rates similar to those of bismuth-based and concomitant quadruple therapies as first first-line treatment of H. pylori in clinical practice in Italy [
      • De Francesco V.
      • Pontone S.
      • Bellesia A.
      • et al.
      Quadruple, sequential, and concomitant first-line therapies for H. pylori eradication: a prospective, randomized study.
      ,
      • Fiorini G.
      • Zullo A.
      • Saracino I.M.
      • et al.
      Pylera and sequential therapy for first-line Helicobacter pylori eradication: a culture-based study in real clinical practice.
      . Thus, according to previous Italian guidelines, sequential therapy appears to be a valid option in Italy. National registries reporting the efficacy and side effects of the different regimens in clinical practice should be encouraged to improve the empirical first-line treatment of H. pylori infection in Italy.
      The standard triple therapy, including a proton pump inhibitor (PPI) plus clarithromycin and amoxicillin or metronidazole/tinidazole, is highly effective in subjects with clarithromycin sensitive H. pylori strains, but fails against strains resistant to clarithromycin, with eradication rates lower than 70% [
      • Liou J.-M.
      • Chen C.-C.
      • Chang C.-Y.
      • et al.
      Sequential therapy for 10 days versus triple therapy for 14 days in the eradication of Helicobacter pylori in the community and hospital populations: a randomised trial.
      ]. Due to the paucity of data on the prevalence of clarithromycin resistance in many areas worldwide, it has been proposed that a high local eradication rate (> 85%) with this regimen should be considered a surrogate marker of the low prevalence of clarithromycin resistance. A meta-analysis of 45 randomized clinical trials has shown that 14 days is the optimal duration of this regimen achieving significantly higher eradication rates than 7- and 10-day treatment [
      • Yuan Y.
      • Ford A.C.
      • Khan K.J.
      • et al.
      Optimum duration of regimens for Helicobacter pylori eradication.
      ]. A 14-day standard triple therapy should be used in Italy as first-line treatment only in areas with a known low prevalence of clarithromycin resistance (<15%), in patients without previous use of macrolide, or where this regimen has been proven to achieve high eradication rates.
      The choice between single capsule, bismuth-containing quadruple therapy, or a clarithromycin-containing regimen as first-line eradication regimens should be based on patients’ previous antibiotic exposure and the presence of allergy to amoxicillin. It is well known that previous use of macrolides, even for infections other than H. pylori, may increase the likelihood that a patient harbors an H. pylori strain resistant to this class of antibiotics [
      • McNulty C.A.
      • Lasseter G.
      • Shaw I.
      • et al.
      Is Helicobacter pylori antibiotic resistance surveillance needed and how can it be delivered?.
      ]. Also, single capsule, bismuth-containing quadruple therapy should be preferred in a geographical area with a well-known high prevalence of dual resistance to clarithromycin and metronidazole (>15%). In such areas, high-dose PPI-amoxicillin dual therapy can be considered as an alternative to bismuth quadruple therapy, in particular where bismuth, tetracycline, or Pylera® are not available, as this therapy avoids the issue of clarithromycin and metronidazole resistance all together [
      • Yang X.
      • Wang J.X.
      • Han S.X.
      • et al.
      High dose dual therapy versus bismuth quadruple therapy for Helicobacter pylori eradication treatment: A systematic review and meta-analysis.
      ]. Generally speaking, bismuth quadruple therapy should be preferred over a clarithromycin-containing regimen, in particular in the setting of a high rate of dual resistance.
      Acid-suppressive drugs play a crucial role in eradication therapy by increasing the gastric bioavailability of antimicrobials and by increasing the number of dividing H. pylori, making the bacteria more susceptible to the action of antibiotics [
      • Yan T.L.
      • Gao J.G.
      • Wang J.H.
      • et al.
      Current status of Helicobacter pylori eradication and risk factors for eradication failure.
      ]. A meta-analysis has demonstrated that new-generation PPIs (i.e., esomeprazole or rabeprazole) are associated with significantly higher eradication rates than those obtained with first-generation PPIs (i.e., omeprazole, lansoprazole, or pantoprazole) [
      • McNicholl A.G.
      • Linares P.M.
      • Nyssen O.P.
      • et al.
      Meta-analysis: esomeprazole or rabeprazole vs. first-generation pump inhibitors in the treatment of Helicobacter pylori infection.
      ]. Moreover, the eradication regimen is optimized by doubling the dose of PPI [
      • Gisbert J.P.
      • McNicholl A.G.
      Optimization strategies aimed to increase the efficacy of H. pylori eradication therapies.
      ]. To further strengthen the role of acid suppression in H. pylori eradication, recent studies from Japan have shown that triple regimens based on the use of vonoprazan, a potassium-competitive acid blocker (P-CAB) achieve higher eradication rates than those obtained with PPIs [
      • Kiyotoki S.
      • Nishikawa J.
      • Sakaida I.
      Efficacy of vonoprazan for Helicobacter pylori eradication.
      ]. This occurs because P-CABs achieve stronger, longer-lasting suppression of gastric acid secretion compared to PPIs [
      • Kiyotoki S.
      • Nishikawa J.
      • Sakaida I.
      Efficacy of vonoprazan for Helicobacter pylori eradication.
      ].
      Table 1 summarizes the available eradication regimens currently used with doses and indications. Recommended options for first-line therapy are indicated in Fig. 1.
      Table 1Eradication regimens used in clinical practice in Italy: their duration and when should they be used.
      TypeRegimenDurationWhen
      Concomitant therapyPPI high dose bid + amoxicillin 1 g bid + clarithromycin 500 mg bid + tinidazole 500 mg bid14 daysFirst line.

      Only if no previous exposure to clarithromycin and/or well known low (i.e. <15%) prevalence of dual resistance.
      Second line (if Pylera fails)
      Single capsule (Pylera) bismuth therapyPP high dose I bid + Pylera 3 tablets qid10 daysFirst line.

      Second line (if concomitant fails)
      Sequential TherapyPPI high dose bid + amoxicillin 1 g bid for 5 days followed by PPI bid + clarithromycin 500 mg bid + tinidazole 500 mg bid for 5 more days10 daysFirst line.

      Only if no previous exposure to clarithromycin and/or well known low (i.e. <15%) prevalence of dual resistance.
      Second line (if Pylera fails)
      Triple therapyPPI high dose bid + amoxicillin 1g bid + clarithromycin 500 mg bid14 daysFirst line (only if known <15% clarithromycin resistance)
      Levofloxacin-containing triple therapyPPI high dose bid + amoxicillin 1 g bid + levofloxacin 250 mg bid14 daysSecond line (if Pylera fails).

      Third line (if Pylera and concomitant therapy fail)
      Rifabutin containing triple therapyPPI high dose bid + amoxicillin 1 g bid + rifabutin 150 mg bid12 daysRescue therapy
      High dose PPI amoxicillin dual therapyPPI high dose tid + amoxicillin 1 g tid14 daysThird line (if Pylera and levofloxacin triple therapy fail).

      Rescue therapy
      bid: twice a day; tid: three times a day; qid: four times a day, PPI: proton pump inhibitor, mg:milligrams, g: grams.
      low asterisk Only if no previous exposure to clarithromycin and/or well known low (i.e. <15%) prevalence of dual resistance.
      Fig 1
      Fig. 1Therapeutic algorithm for H. pylori eradication.
      *only if no previous exposure to clarithromycin or knowledge of low prevalence of dual resistance.

      3.2.2 Which eradication regimen should be used following first-line therapy failure in Italy?

      Statement 12: If first-line therapy with single-capsule bismuth quadruple regimen failed, levofloxacin containing regimen should be used as second line treatment, particularly in patients previously exposed to clarithromycin or in a geographical area of known high dual resistance. If a clarithromycin-containing regimen was used as the first line, single-capsule bismuth quadruple therapy should be used as a second-line treatment.
      Evidence level: low; Grade of recommendation: strong
      Treating H. pylori infection following therapy failures is increasingly more complex, mainly due to the development of bacterial resistance to antibiotics. In particular, not only the rate but also the MIC values of resistance have been found to affect therapy success [
      • De Francesco V.
      • Zullo A.
      • Fiorini G.
      • et al.
      Role of MIC levels of resistance to clarithromycin and metronidazole in Helicobacter pylori eradication.
      ]. Bacterial resistance easily develops towards clarithromycin, metronidazole, and levofloxacin, whilst it remains distinctly low for amoxicillin and tetracycline, even after repeated use [
      • De Francesco V.
      • Giorgio F.
      • Hassan C.
      • et al.
      Worldwide H. pylori antibiotic resistance: a systematic review.
      ]. Therefore, when prescribing retreatment, there is a rationale for changing the antibiotics used previously, with the exception of amoxicillin and tetracycline. If the first-line therapy was a clarithromycin-containing regimen (concomitant or sequential), single capsule bismuth quadruple therapy should be the preferred second-line treatment (Fig. 1). On the other side, if the single capsule bismuth concomitant therapy was the first-line therapy, a 14-day levofloxacin-containing regimen should represent the preferred second-line therapeutic option [
      • Caldas M.
      • Pérez-Aisa Á.
      • Castro-Fernández M.
      • et al.
      European registry on helicobacter pylori management: effectiveness of first and second-line treatment in Spain.
      ,
      • Zagari R.M.
      • Romano M.
      • Ojetti V.
      • et al.
      Guidelines for the management of Helicobacter pylori infection in Italy: the III Working Group Consensus Report 2015.
      (Fig. 1). The levofloxacin-containing regimen should only be used as rescue treatment given the rapidly rising prevalence of quinolone resistance and the recent warnings about possible serious adverse events of fluoroquinolones. However, if the patients have never been exposed to clarithromycin previously, a second attempt should include a clarithromycin-containing regimen [
      • De Francesco V.
      • Zullo A.
      • Fiorini G.
      • et al.
      Role of MIC levels of resistance to clarithromycin and metronidazole in Helicobacter pylori eradication.
      ,
      • De Francesco V.
      • Giorgio F.
      • Hassan C.
      • et al.
      Worldwide H. pylori antibiotic resistance: a systematic review.
      ,
      • Kim S.Y.
      • Lee S.W.
      • Choe J.W.
      • et al.
      Helicobacter pylori eradication rates of concomitant and sequential therapies in Korea.
      (Fig. 1).

      3.2.3 Which eradication regimen should be used in case the second-line, or third-line therapy fails in Italy?

      Statement 13: In case of second-line treatment failure, a 14-day levofloxacin-containing triple therapy, if not used already as a second-line regimen, or a 14 day high dose dual therapy may be used as an empirical third-line regimen.
      Evidence level: low; Grade of recommendation: weak
      Statement 14: In the case of third-line treatment failure, tailored therapy based on EGDS followed by culture and antimicrobial susceptibility testing should be the recommended procedure.
      Evidence level: very low; Grade of recommendation: weak

      3.2.4 What should be the preferred rescue therapy after multiple eradication failures?

      Statement 15: Rifabutin based 12-days triple therapy or 14-day high dose dual therapy should be used in the case of multiple eradication failures
      Evidence level: very low; Grade of recommendation: weak
      If the second-line therapy (quadruple bismuth or clarithromycin-containing regimen) also fails, a triple levofloxacin-containing regimen, preferably for 14 days, is suggested as third-line therapy, if not used before [
      • Chen P.-Y.
      • Wu M.-S.
      • Chen C.-Y.
      • et al.
      Systematic review with meta-analysis: the efficacy of levofloxacin triple therapy as the first- or second-line treatments of Helicobacter pylori infection.
      ,
      • Gisbert J.P.
      • Gisbert J.L.
      • Marcos S.
      • et al.
      Third-line rescue therapy with levofloxacin is more effective than rifabutin rescue regimen after two Helicobacter pylori treatment failures.
      ,
      • Gisbert J.P.
      H. pylori Study Group of the Spanish Gastroenterology Association
      Letter: third-line rescue therapy with levofloxacin after failure of two treatments to eradicate Helicobacter pylori infection.
      ] (Fig. 1). A triple regimen with levofloxacin could be used as second-line treatment only if a quadruple therapy with bismuth has been used as first-line therapy in an area with high prevalence of H. pylori strains with dual resistance to clarithromycin and metronidazole [
      • Moayyedi P.
      • Lacy B.E.
      • Andrews C.N.
      • et al.
      ACG and CAG clinical guideline: management of dyspepsia.
      ,
      • Zagari R.M.
      • Romano M.
      • Ojetti V.
      • et al.
      Guidelines for the management of Helicobacter pylori infection in Italy: the III Working Group Consensus Report 2015.
      (Fig. 1).
      Several consensus groups have, over time, recommended "tailored" therapy for refractory H. pylori infection based on in vitro antimicrobial susceptibility testing. Despite this, the strength of the recommendations has never been particularly strong [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ,
      • Liou J.-M.
      • Malfertheiner P.
      • Lee Y.-C.
      • et al.
      Screening and eradication of Helicobacter pylori for gastric cancer prevention: the Taipei global consensus.
      . The efficacy of "tailored" therapy has shown inconsistent results in the literature, with eradication rates ranging from 74% to 98.7% in areas with resistance rates to clarithromycin ranging from 51% to 95%, levofloxacin from 6% to 52%, and metronidazole from 43% to 100% [
      • Liou J.-M.
      • Chen P.-Y.
      • Luo J.-C.
      • et al.
      Efficacies of genotypic resistance-guided vs empirical therapy for refractory helicobacter pylori infection.
      ,
      • Yu L.
      • Luo L.
      • Long X.
      • et al.
      Susceptibility-guided therapy for Helicobacter pylori infection treatment failures.
      ,
      • Cammarota G.
      • Martino A.
      • Pirozzi G.
      • et al.
      High efficacy of 1-week doxycycline- and amoxicillin-based quadruple regimen in a culture-guided, third-line treatment approach for Helicobacter pylori infection.
      ,
      • Costa S.
      • Soares J.-B.
      • Gonçalves R.
      Efficacy and tolerability of culture-guided treatment for Helicobacter pylori infection.
      ,
      • Fiorini G.
      • Vakil N.
      • Zullo A.
      • et al.
      Culture-based selection therapy for patients who did not respond to previous treatment for Helicobacter pylori infection.
      ,
      • Gasbarrini A.
      • Ojetti V.
      • Armuzzi A.
      • et al.
      Efficacy of a multistep strategy for Helicobacter pylori eradication.
      ,
      • Tay C.Y.
      • Windsor H.M.
      • Thirriot F.
      • et al.
      Helicobacter pylori eradication in Western Australia using novel quadruple therapy combinations.
      ,
      • Vicente R.
      • Sicilia B.
      • Gallego S.
      • et al.
      Helicobacter pylori eradication in patients with peptic ulcer after two treatment failures: a prospective culture-guided study.
      ,
      • Yahav J.
      • Samra Z.
      • Niv Y.
      • et al.
      Susceptibility-guided vs. empiric retreatment of Helicobacter pylori infection after treatment failure.
      ].
      Moreover, a recent meta-analysis showed that therapy based on antimicrobial susceptibility assessment was superior to empiric therapy only in the first line of treatment, whereas for the second and third line of treatments the evidence was less strong [
      • López-Góngora S.
      • Puig I.
      • Calvet X.
      • et al.
      Systematic review and meta-analysis: susceptibility-guided versus empirical antibiotic treatment for Helicobacter pylori infection.
      ].
      Overall, in cases of failure with three lines of treatment, this panel argues in favor of targeted therapy based on culture and in vitro antimicrobial susceptibility testing, where available (Fig. 1). However, careful empiric therapy, based on the epidemiology and on the patient's medical history, may be an alternative if culture testing is not available.
      After multiple treatment failures, several salvage therapies have been suggested (Fig. 1). In particular, there is renewed interest in dual therapy with PPIs and high-dose amoxicillin for 14 days (i.e., omeprazole or esomeprazole 40 mg and amoxicillin 1 g, both three times daily), which has been shown to achieve cure rates similar to those of other more complex and less safe therapies [
      • Miehlke S.
      • Hansky K.
      • Schneider-Brachert W.
      • et al.
      Randomized trial of rifabutin-based triple therapy and high-dose dual therapy for rescue treatment of Helicobacter pylori resistant to both metronidazole and clarithromycin.
      ]. Two recent meta-analyses showed that high-dose dual therapy achieved similar eradication rates compared with bismuth-based quadruple therapies [
      • Gao C.P.
      • Zhou Z.
      • Wang J.Z.
      • et al.
      Efficacy and safety of high-dose dual therapy for Helicobacter pylori rescue therapy: a systematic review and meta-analysis.
      ] or other salvage therapies [
      • Yang X.
      • Wang J.-X.
      • Han S.-X.
      • et al.
      High dose dual therapy versus bismuth quadruple therapy for Helicobacter pylori eradication treatment: a systematic review and meta-analysis.
      ]. Further favoring this therapeutic approach are both the low rate of side effects and the lower cost (52.36 euros in Italy) compared to Pylera® (74.04 euros) [
      • Nyssen O.P.
      • Perez-Aisa A.
      • Castro-Fernandez M.
      • et al.
      European Registry on Helicobacter pylori management: single-capsule bismuth quadruple therapy is effective in real-world clinical practice.
      ].
      Another salvage therapy that has proven to be effective after multiple therapeutic failures is the 12-day rifabutin-amoxicillin triple therapy (i.e., PPI standard dose b.i.d. + amoxicillin 1 g b.i.d. + rifabutin 150 mg b.i.d.) [
      • Fiorini G.
      • Zullo A.
      • Vakil N.
      • et al.
      Rifabutin triple therapy is effective in patients with multidrug-resistant strains of Helicobacter pylori.
      ,
      • Fiorini G.
      • Saracino I.M.
      • Zullo A.
      • et al.
      Rescue therapy with bismuth quadruple regimen in patients with Helicobacter pylori -resistant strains.
      . A recent large study found that this regimen achieves eradication rates greater than 80% when used in patients with three or more treatment failures [
      • Saracino I.M.
      • Pavoni M.
      • Zullo A.
      • et al.
      Antibiotic resistance and therapy outcome in H. pylori eradication failure patients.
      ]. Based on potential bone marrow toxicity, the utility for treating mycobacterial infection in patients with HIV, and a very high cost, the expert panel suggests that rifabutin therapy should be used only after failure of all other regimens and in selected patients with severe gastric diseases (i.e., MALT-lymphoma, bleeding peptic ulcer). It is also suggested to perform tests for tuberculosis such as Mantoux, Quantiferon, or ELISPOT (Enzyme-Linked ImmunoSpot) tests before starting therapy with rifabutin because this drug can promote the emergence of M. tuberculosis strains resistant to common anti-tuberculosis. Finally, given the potential myelotoxicity, performing blood counts is also recommended.

      3.3 What is the role of probiotics in the therapeutic management of H. pylori infection?

      Statement 16: In patients with H. pylori infection, supplementation with probiotics in addition to eradication therapy should be considered to reduce the rate of side effects associated with the eradication therapy.
      Evidence level: low; Grade of recommendation: weak
      Probiotic supplementation in the treatment of H. pylori infection has been proposed to increase eradication rates and/or decrease adverse events related to antibiotics used in eradication treatment regimens [
      • Patel A.
      • Shah N.
      • Prajapati J.B.
      Clinical application of probiotics in the treatment of Helicobacter pylori infection – a brief review.
      ]. The effect of probiotics on the eradication rate remains, to date, controversial due to inconsistent data and the reduced quality of available studies. A meta-analysis of 19 randomized controlled trials including 2,730 patients evaluated the impact of six probiotic mixtures on the efficacy of H. pylori eradication regimens, consisting mainly of triple therapy containing clarithromycin [
      • McFarland L.V.
      • Huang Y.
      • Wang L.
      • et al.
      Systematic review and meta-analysis: multi-strain probiotics as adjunct therapy for Helicobacter pylori eradication and prevention of adverse events.
      ]. The eradication rate was significantly higher in patients who had used probiotics than in those who had not (86% vs 77%, respectively). In addition, probiotic use was associated with a decrease in adverse events (particularly diarrhea) of 14%. On the other hand, a prospective multicenter study in Italy showed no benefit from probiotic supplementation in patients receiving quadruple therapy with bismuth [
      • Fallone C.A.
      • Chiba N.
      • van Zanten S.V.
      • et al.
      The Toronto Consensus for the Treatment of Helicobacter pylori Infection in Adults.
      ].
      More high-quality studies are certainly needed to better clarify which strains are effective and in which contexts. European guidelines, in any case, suggest the use of probiotics only to reduce antibiotic-related adverse events [
      • Malfertheiner P.
      • Megraud F.
      • O'Morain C.A.
      • et al.
      Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
      ].
      Tools facilitating the implementation of the current guideline are provided at the end of this position paper, namely Fig. 1 (Therapeutic algorithm for H. pylori eradication) and Table 1 (Eradication regimens used in clinical practice in Italy).

      Conflict of interest

      None declared.

      APPENDIX A

      SIGE National Council full members’ names and affiliations
      - Antonio BENEDETTI, Gastroenterology, Hepatology and Urgent Digestive Endoscopy Unit, Polytechnic University of Marche, Ancona, Italy.
      - Bruno ANNIBALE, Digestive Diseases and Liver Unit, Sant'Andrea University Hospital, Rome, Italy.
      - Patrizia BURRA, University of Padova, Department of Surgical, Oncological and Gastroenterological Sciences, Padova, Italy.
      - Marcello Fabio MAIDA, Unit of Gastroenterology, Ospedali Riuniti S. Elia-Raimondi, Caltanissetta, Italy.
      - Francesco LUZZA, University "Magna Graecia”, Catanzaro, Italy.
      - Luigi RICCIARDIELLO, University of Bologna, Department of Medical and Surgical Sciences, Bologna, Italy.
      - Maurizio VECCHI, University of Milan, Milano, Italy.
      - Luca FRULLONI, Department of Medicine, University of Verona, Verona, Italy.
      - Alessandro REPICI, Humanitas Research Hospital and Humanitas University, Digestive Endoscopy Unit, Milano, Italy.
      - Edoardo Vincenzo SAVARINO, Department of Surgery, Oncology and Gastroenterology, University of Padova, Padova, Italy.

      APPENDIX B

      SIED National Council full members’ names and affiliations
      - Luigi PASQUALE, Unit of Gastroenterology and Digestive Endoscopy, Hospital of Ariano Irpino, Avellino, Italy.
      - Antonio PISANI, Gastroenterology Unit “Saverio De Bellis” Research Hospital, Castellana Grotte, Italy.
      - Antonietta LAMAZZA, Digestive and Operative Endoscopy Unit, Policlinico Umberto I, "Sapienza University, Rome, Italy.
      - Gianpaolo CENGIA, Digestive Endoscopy Unit, Manerbio Hospital, Brescia, Italy.
      - Enrico CILIBERTO, Gastroenterology and Digestive Endoscopy Unit, San Giovanni di Dio Hospital, Crotone, Italy.
      - Rita Luisa CONIGLIARO, Gastroenterology and Digestive Endoscopy Unit, Modena University Hospital, Modena, Italy.
      - Paola DA MASSA CARRARA, Gastroenterology Unit, Usl Toscana, Pistoia, Italy.
      - Bastianello GERMANÀ, Gastroenterology and Digestive Endoscopy Unit, S. Martino Hospital, Belluno, Italy.

      References

        • Hooi J.K.Y.
        • Lai W.Y.
        • Ng W.K.
        • et al.
        Global Prevalence of Helicobacter pylori infection: systematic review and meta-analysis.
        Gastroenterology. 2017; 153: 420-429
        • Zagari R.M.
        • Rabitti S.
        • Eusebi L.H.
        • et al.
        Treatment of Helicobacter pylori infection: a clinical practice update.
        Eur J ClinInvest. 2018; 48
        • Malfertheiner P.
        • Megraud F.
        • O'Morain C.A.
        • et al.
        Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.
        Gut. 2017; 66: 6-30
        • Balshem H.
        • Helfand M.
        • Schünemann H.J.
        • et al.
        GRADE guidelines: 3. Rating the quality of evidence.
        J Clin Epidemiol. 2011; 64: 401-406
        • Eusebi L.H.
        • Black C.J.
        • Howden C.W.
        • et al.
        Effectiveness of management strategies for uninvestigated dyspepsia: systematic review and network meta-analysis.
        BMJ. 2019; 367: l6483
        • Moayyedi P.
        • Lacy B.E.
        • Andrews C.N.
        • et al.
        ACG and CAG clinical guideline: management of dyspepsia.
        Am J Gastroenterol. 2017; 112: 988-1013
        • Beresniak A.
        • Malfertheiner P.
        • Franceschi F.
        • et al.
        Helicobacter pylori “Test-and-Treat” strategy with urea breath test: a cost-effective strategy for the management of dyspepsia and the prevention of ulcer and gastric cancer in Spain-Results of the Hp-Breath initiative.
        Helicobacter. 2020; 25: e12693
        • Melcarne L.
        • García-Iglesias P.
        • Calvet X.
        Management of NSAID-associated peptic ulcer disease.
        Exp Rev Gastroenterol Hepatol. 2016; 10: 723-733
        • Fashner J.
        • Gitu A.C.
        Diagnosis and treatment of peptic ulcer disease and H. pylori infection.
        Am Fam Physician. 2015; 91: 236-242
        • Huang J.Q.
        • Sridhar S.
        • Hunt R.H.
        Role of Helicobacter pylori infection and non-steroidal anti-inflammatory drugs in peptic-ulcer disease: a meta-analysis.
        Lancet (London, England). 2002; 359: 14-22
        • Sostres C.
        • Carrera-Lasfuentes P.
        • Benito R.
        • et al.
        Peptic ulcer bleeding risk. The role of Helicobacter pylori Infection in NSAID/Low-Dose Aspirin Users.
        Am J Gastroenterol. 2015; 110: 684-689
        • Muhsen K.
        • Cohen D.
        Helicobacter pylori infection and iron stores: a systematic review and meta-analysis.
        Helicobacter. 2008; 13: 323-340
        • Qu X.-H.
        • Huang X.-L.
        • Xiong P.
        • et al.
        Does Helicobacter pylori infection play a role in iron deficiency anemia? A meta-analysis.
        World J Gastroenterol. 2010; 16: 886-896
        • Huang X.
        • Qu X.
        • Yan W.
        • et al.
        Iron deficiency anaemia can be improved after eradication of Helicobacter pylori.
        Postgrad Med J. 2010; 86: 272-278
        • Yuan W.
        • Li Y.
        • Kehu Y.
        • et al.
        Iron deficiency anemia in Helicobacter pylori infection: meta-analysis of randomized controlled trials.
        Scand J Gastroenterol. 2010; 45: 665-676
        • Zhang Z.-F.
        • Yang N.
        • Zhao G.
        • et al.
        Effect of Helicobacter pylori eradication on iron deficiency.
        Chin Med J (Engl). 2010; 123: 1924-1930
        • Gravina A.G.
        • Zagari R.M.
        • De Musis C.
        • et al.
        Helicobacter pylori and extragastric diseases: A review.
        World J Gastroenterol. 2018; 24: 3204-3221
        • Gravina A.G.
        • Priadko K.
        • Ciamarra P.
        • et al.
        Extra-gastric manifestations of Helicobacter pylori Infection.
        J ClinMed. 2020; 9: E3887
        • Senkovich O.
        • Ceaser S.
        • McGee D.J.
        • et al.
        Unique host iron utilization mechanisms of Helicobacter pylori revealed with iron-deficient chemically defined media.
        Infect Immun. 2010; 78: 1841-1849
        • Ozkasap S.
        • Yarali N.
        • Isik P.
        • et al.
        The role of prohepcidin in anemia due to Helicobacter pylori infection.
        Pediatr Hematol Oncol. 2013; 30: 425-431
        • Mendoza E.
        • Duque X.
        • Hernández Franco J.I.
        • et al.
        Association between Active H. pylori infection and iron deficiency assessed by serum hepcidin levels in school-age children.
        Nutrients. 2019; 11: E2141
        • Hudak L.
        • Jaraisy A.
        • Haj S.
        • et al.
        An updated systematic review and meta-analysis on the association between Helicobacter pylori infection and iron deficiency anemia.
        Helicobacter. 2017; : 22
        • Stabler S.P.
        Vitamin B12 deficiency.
        N Engl J Med. 2013; 368: 2041-2042
        • Lahner E.
        • Persechino S.
        • Annibale B.
        Micronutrients (Other than iron) and Helicobacter pylori infection: a systematic review.
        Helicobacter. 2012; 17: 1-15
        • Campuzano-Maya G.
        Hematologic manifestations of Helicobacter pylori infection.
        World J Gastroenterol. 2014; 20: 12818-12838
        • Valdes-Socin H.
        • Leclercq P.
        • Polus M.
        • et al.
        [Chronic autoimmune gastritis : a multidisciplinary management].
        Rev Med Liege. 2019; 74: 598-605
        • Kodama M.
        • Kitadai Y.
        • Ito M.
        • et al.
        Immune response to CagA protein is associated with improved platelet count after Helicobacter pylori eradication in patients with idiopathic thrombocytopenic purpura.
        Helicobacter. 2007; 12: 36-42
        • Asahi A.
        • Nishimoto T.
        • Okazaki Y.
        • et al.
        Helicobacter pylori eradication shifts monocyte Fcgamma receptor balance toward inhibitory FcgammaRIIB in immune thrombocytopenic purpura patients.
        J Clin Invest. 2008; 118: 2939-2949
        • Testerman T.L.
        • Morris J.
        Beyond the stomach: an updated view of Helicobacter pylori pathogenesis, diagnosis, and treatment.
        World J Gastroenterol. 2014; 20: 12781-12808
        • Satoh T.
        • Pandey J.P.
        • Okazaki Y.
        • et al.
        Single nucleotide polymorphism of interleukin-1beta associated with Helicobacter pylori infection in immune thrombocytopenic purpura.
        Tissue Antigens. 2009; 73: 353-357
        • Suvajdzić N.
        • Stanković B.
        • Artiko V.
        • et al.
        Helicobacter pylori eradication can induce platelet recovery in chronic idiopathic thrombocytopenic purpura.
        Platelets. 2006; 17: 227-230
        • Jackson S.C.
        • Beck P.
        • Buret A.G.
        • et al.
        Long term platelet responses to Helicobacter pylori eradication in Canadian patients with immune thrombocytopenic purpura.
        Int J Hematol. 2008; 88: 212-218
        • Warburton-Timms V.J.
        • Charlett A.
        • Valori R.M.
        • et al.
        The significance of cagA(+) Helicobacter pylori in reflux oesophagitis.
        Gut. 2001; 49: 341-346
        • Zamani M.
        • Alizadeh-Tabari S.
        • Hasanpour A.H.
        • et al.
        Systematic review with meta-analysis: association of Helicobacter pylori infection with gastro-oesophageal reflux and its complications.
        Aliment Pharmacol Ther. 2021; 54: 988-998
        • Rokkas T.
        • Pistiolas D.
        • Sechopoulos P.
        • et al.
        Relationship between Helicobacter pylori infection and esophageal neoplasia: a meta-analysis.
        Clin Gastroenterol Hepatol. 2007; 5 (1417.e1-2): 1413-1417
        • Laine L.
        • Sugg J.
        Effect of Helicobacter pylori eradication on development of erosive esophagitis and gastroesophageal reflux disease symptoms: a post hoc analysis of eight double blind prospective studies.
        Am J Gastroenterol. 2002; 97: 2992-2997
        • Yaghoobi M.
        • Farrokhyar F.
        • Yuan Y.
        • et al.
        Is there an increased risk of GERD after Helicobacter pylori eradication?: a meta-analysis.
        Am J Gastroenterol. 2010; 105 (quiz 1006, 1014): 1007-1013
        • Qian B.
        • Ma S.
        • Shang L.
        • et al.
        Effects of Helicobacter pylori eradication on gastroesophageal reflux disease.
        Helicobacter. 2011; 16: 255-265
        • Moayyedi P.
        • Bardhan C.
        • Young L.
        • et al.
        Helicobacter pylori eradication does not exacerbate reflux symptoms in gastroesophageal reflux disease.
        Gastroenterology. 2001; 121: 1120-1126
        • Kuipers E.J.
        • Uyterlinde A.M.
        • Peña A.S.
        • et al.
        Increase of Helicobacter pylori-associated corpus gastritis during acid suppressive therapy: implications for long-term safety.
        Am J Gastroenterol. 1995; 90: 1401-1406
        • Kuipers E.J.
        • Lundell L.
        • Klinkenberg-Knol E.C.
        • et al.
        Atrophic gastritis and Helicobacter pylori infection in patients with reflux esophagitis treated with omeprazole or fundoplication.
        N Engl J Med. 1996; 334: 1018-1022
        • García Rodríguez L.A.
        • Lagergren J.
        • Lindblad M.
        Gastric acid suppression and risk of oesophageal and gastric adenocarcinoma: a nested case control study in the UK.
        Gut. 2006; 55: 1538-1544
        • Mukaisho K.
        • Hagiwara T.
        • Nakayama T.
        • et al.
        Potential mechanism of corpus-predominant gastritis after PPI therapy in Helicobacter pylori-positive patients with GERD.
        World J Gastroenterol. 2014; 20: 11962-11965
        • Sgambato D.
        • Visciola G.
        • Ferrante E.
        • et al.
        Prevalence of Helicobacter pylori infection in sexual partners of H. pylori-infected subjects: Role of gastroesophageal reflux.
        United Eur Gastroenterol J. 2018; 6: 1470-1476
        • Ferwana M.
        • Abdulmajeed I.
        • Alhajiahmed A.
        • et al.
        Accuracy of urea breath test in Helicobacter pylori infection: meta-analysis.
        World J Gastroenterol. 2015; 21: 1305-1314
        • Kayali S.
        • Aloe R.
        • Bonaguri C.
        • Gaiani F.
        • et al.
        Non-invasive tests for the diagnosis of Helicobacter pylori: state of the art.
        Acta Biomed. 2018; 89: 58-64
        • Makristathis A.
        • Hirschl A.M.
        • Mégraud F.
        • et al.
        Review: Diagnosis of Helicobacter pylori infection.
        Helicobacter. 2019; 24: e12641
        • Best L.M.
        • Takwoingi Y.
        • Siddique S.
        • et al.
        Non-invasive diagnostic tests for Helicobacter pylori infection.
        Cochrane Database Syst Rev. 2018; 3CD012080
        • Gisbert J.P.
        • de la Morena F.
        • Abraira V.
        Accuracy of monoclonal stool antigen test for the diagnosis of H. pylori infection: a systematic review and meta-analysis.
        Am J Gastroenterol. 2006; 101: 1921-1930
        • Calvet X.
        • Lario S.
        • Ramírez-Lázaro M.J.
        • et al.
        Accuracy of monoclonal stool tests for determining cure of Helicobacter pylori infection after treatment.
        Helicobacter. 2010; 15: 201-205
        • Levine A.
        • Shevah O.
        • Shabat-Sehayek V.
        • et al.
        Masking of 13C urea breath test by proton pump inhibitors is dependent on type of medication: comparison between omeprazole, pantoprazole, lansoprazole and esomeprazole.
        Aliment Pharmacol Ther. 2004; 20: 117-122
        • Asfeldt A.M.
        • Løchen M.-L.
        • Straume B.
        • et al.
        Accuracy of a monoclonal antibody-based stool antigen test in the diagnosis of Helicobacter pylori infection.
        Scand J Gastroenterol. 2004; 39: 1073-1077
        • Sánchez-Delgado J.
        • Gené E.
        • Suárez D.
        • et al.
        Has H. pylori prevalence in bleeding peptic ulcer been underestimated? A meta-regression.
        Am J Gastroenterol. 2011; 106: 398-405
        • Zagari R.M.
        • Romano M.
        • Ojetti V.
        • et al.
        Guidelines for the management of Helicobacter pylori infection in Italy: the III Working Group Consensus Report 2015.
        Dig Liver Dis. 2015; 47: 903-912
        • Darma A.
        • Nugroho B.S.T.
        • Yoanna V.
        • et al.
        Comparison of Helicobacter pylori stool antigen, salivary IgG, serum IgG, and serum IgM as diagnostic markers of H. pylori infection in children.
        Iran J Microbiol. 2019; 11: 206-211
        • Pimentel-Nunes P.
        • Libânio D.
        • Marcos-Pinto R.
        • et al.
        Management of epithelial precancerous conditions and lesions in the stomach (MAPS II): European Society of Gastrointestinal Endoscopy (ESGE), European Helicobacter and Microbiota Study Group (EHMSG), European Society of Pathology (ESP), and Sociedade Portuguesa de EndoscopiaDigestiva (SPED) guideline update 2019.
        Endoscopy. 2019; 51: 365-388
        • Benoit A.
        • Hoyeau N.
        • Fléjou J.-F.
        Diagnosis of Helicobacter pylori infection on gastric biopsies: Standard stain, special stain or immunohistochemistry?.
        Ann Pathol. 2018; 38: 363-369
        • Dixon M.F.
        • Genta R.M.
        • Yardley J.H.
        • et al.
        Classification and grading of gastritis. The updated Sydney System. International Workshop on the Histopathology of Gastritis, Houston 1994.
        Am J Surg Pathol. 1996; 20: 1161-1181
        • el-Zimaity H.M.
        • al-Assi M.T.
        • Genta R.M.
        • et al.
        Confirmation of successful therapy of Helicobacter pylori infection: number and site of biopsies or a rapid urease test.
        Am J Gastroenterol. 1995; 90: 1962-1964
        • Woo J.S.
        • el-Zimaity H.M.
        • Genta R.M.
        • et al.
        The best gastric site for obtaining a positive rapid ureas test.
        Helicobacter. 1996; 1: 256-259
        • Wong A.
        • Ching S.S.
        • Long A.S.
        The use of a second biopsy from the gastric body for the detection of Helicobacter pylori using rapid urease test.
        Singapore Med J. 2014; 55: 644-647
        • Osaki T.
        • Mabe K.
        • Hanawa T.
        • et al.
        Urease-positive bacteria in the stomach induce a false-positive reaction in a urea breath test for diagnosis of Helicobacter pylori infection.
        J Med Microbiol. 2008; 57: 814-819
        • Ierardi E.
        • Giorgio F.
        • Iannone A.
        • et al.
        Noninvasive molecular analysis of Helicobacter pylori: Is it time for tailored first-line therapy?.
        World J Gastroenterol. 2017; 23: 2453-2458
        • Losurdo G.
        • Giorgio F.
        • Pricci M.
        • et al.
        Helicobacter pylori primary and secondary genotypic resistance to clarithromycin and levofloxacin detection in stools: A 4-Year scenario in Southern Italy.
        Antibiotics (Basel). 2020; 9: E723
        • Fiorini G.
        • Zullo A.
        • Saracino I.M.
        • et al.
        Antibiotic resistance pattern of Helicobacter pylori strains isolated in Italy during 2010-2016.
        Scand J Gastroenterol. 2018; 53: 661-664
        • Fallone C.A.
        • Chiba N.
        • van Zanten S.V.
        • et al.
        The Toronto Consensus for the Treatment of Helicobacter pylori Infection in Adults.
        Gastroenterology. 2016; 151 (e14): 51-69
        • Nyssen O.P.
        • McNicholl A.G.
        • Gisbert J.P.
        Meta-analysis of three-in-one single capsule bismuth-containing quadruple therapy for the eradication of Helicobacter pylori.
        Helicobacter. 2019; 24: e12570
        • Zagari R.M.
        • Romiti A.
        • Ierardi E.
        • et al.
        The “three-in-one” formulation of bismuth quadruple therapy for Helicobacter pylori eradication with or without probiotics supplementation: Efficacy and safety in daily clinical practice.
        Helicobacter. 2018; 23: e12502
        • Tursi A.
        • Franceschi M.
        • Allegretta L.
        • et al.
        Effectiveness and Safety of Pylera® in patients infected by Helicobacter pylori: a multicenter, retrospective, real life study.
        DigDis. 2018; 36: 264-268
        • Di Ciaula A.
        • Scaccianoce G.
        • Venerito M.
        • et al.
        Eradication rates in Italian subjects heterogeneously managed for Helicobacter pylori infection. Time to abandon empiric treatments in Southern Europe.
        J Gastrointestin Liver Dis. 2017; 26: 129-137
        • De Francesco V.
        • Pontone S.
        • Bellesia A.
        • et al.
        Quadruple, sequential, and concomitant first-line therapies for H. pylori eradication: a prospective, randomized study.
        Dig Liver Dis. 2018; 50: 139-141
        • Romano M.
        • Gravina A.G.
        • Nardone G.
        • et al.
        Non-bismuth and bismuth quadruple therapies based on previous clarithromycin exposure are as effective and safe in an area of high clarithromycin resistance: A real-life study.
        Helicobacter. 2020; 25: e12694
        • Nyssen O.P.
        • McNicholl A.G.
        • Megraud F.
        • et al.
        Sequential versus standard triple first-line therapy for Helicobacter pylori eradication.
        Cochrane Database Syst Rev. 2016; CD009034
        • Gatta L.
        • Vakil N.
        • Vaira D.
        • et al.
        Global eradication rates for Helicobacter pylori infection: systematic review and meta-analysis of sequential therapy.
        BMJ. 2013; 347: f4587
        • Fiorini G.
        • Zullo A.
        • Saracino I.M.
        • et al.
        Pylera and sequential therapy for first-line Helicobacter pylori eradication: a culture-based study in real clinical practice.
        Eur J Gastroenterol Hepatol. 2018; 30: 621-625
        • Liou J.-M.
        • Chen C.-C.
        • Chang C.-Y.
        • et al.
        Sequential therapy for 10 days versus triple therapy for 14 days in the eradication of Helicobacter pylori in the community and hospital populations: a randomised trial.
        Gut. 2016; 65: 1784-1792
        • Yuan Y.
        • Ford A.C.
        • Khan K.J.
        • et al.
        Optimum duration of regimens for Helicobacter pylori eradication.
        Cochrane Database Syst Rev. 2013; CD008337
        • McNulty C.A.
        • Lasseter G.
        • Shaw I.
        • et al.
        Is Helicobacter pylori antibiotic resistance surveillance needed and how can it be delivered?.
        Aliment Pharmacol Ther. 2012; 35: 1221-1230
        • Yang X.
        • Wang J.X.
        • Han S.X.
        • et al.
        High dose dual therapy versus bismuth quadruple therapy for Helicobacter pylori eradication treatment: A systematic review and meta-analysis.
        Medicine (Baltimore). 2019; 98: e14396
        • Yan T.L.
        • Gao J.G.
        • Wang J.H.
        • et al.
        Current status of Helicobacter pylori eradication and risk factors for eradication failure.
        World J Gastroenterol. 2020; 26: 4846-4856
        • McNicholl A.G.
        • Linares P.M.
        • Nyssen O.P.
        • et al.
        Meta-analysis: esomeprazole or rabeprazole vs. first-generation pump inhibitors in the treatment of Helicobacter pylori infection.
        Aliment Pharmacol Ther. 2012; 36: 414-425
        • Gisbert J.P.
        • McNicholl A.G.
        Optimization strategies aimed to increase the efficacy of H. pylori eradication therapies.
        Helicobacter. 2017; 22https://doi.org/10.1111/hel.12392
        • Kiyotoki S.
        • Nishikawa J.
        • Sakaida I.
        Efficacy of vonoprazan for Helicobacter pylori eradication.
        Intern Med. 2020; 59: 153-161
        • De Francesco V.
        • Zullo A.
        • Fiorini G.
        • et al.
        Role of MIC levels of resistance to clarithromycin and metronidazole in Helicobacter pylori eradication.
        J Antimicrob Chemother. 2019; 74: 772-774
        • De Francesco V.
        • Giorgio F.
        • Hassan C.
        • et al.
        Worldwide H. pylori antibiotic resistance: a systematic review.
        J Gastrointestin Liver Dis. 2010; 19: 409-414
        • Caldas M.
        • Pérez-Aisa Á.
        • Castro-Fernández M.
        • et al.
        European registry on helicobacter pylori management: effectiveness of first and second-line treatment in Spain.
        Antibiotics. 2020; 10: 13
        • Zagari R.M.
        • Romano M.
        • Ojetti V.
        • et al.
        Guidelines for the management of Helicobacter pylori infection in Italy: the III Working Group Consensus Report 2015.
        DigLiverDis. 2015; 47: 903-912
        • Kim S.Y.
        • Lee S.W.
        • Choe J.W.
        • et al.
        Helicobacter pylori eradication rates of concomitant and sequential therapies in Korea.
        Helicobacter. 2017; : 22
        • Chen P.-Y.
        • Wu M.-S.
        • Chen C.-Y.
        • et al.
        Systematic review with meta-analysis: the efficacy of levofloxacin triple therapy as the first- or second-line treatments of Helicobacter pylori infection.
        Aliment Pharmacol Ther. 2016; 44: 427-437
        • Gisbert J.P.
        • Gisbert J.L.
        • Marcos S.
        • et al.
        Third-line rescue therapy with levofloxacin is more effective than rifabutin rescue regimen after two Helicobacter pylori treatment failures.
        Aliment PharmacolTher. 2006; 24: 1469-1474
        • Gisbert J.P.
        • H. pylori Study Group of the Spanish Gastroenterology Association
        Letter: third-line rescue therapy with levofloxacin after failure of two treatments to eradicate Helicobacter pylori infection.
        Aliment Pharmacol Ther. 2012; 35 (authorreply 1486): 1484-1485
        • Liou J.-M.
        • Malfertheiner P.
        • Lee Y.-C.
        • et al.
        Screening and eradication of Helicobacter pylori for gastric cancer prevention: the Taipei global consensus.
        Gut. 2020; 69: 2093-2112
        • Liou J.-M.
        • Chen P.-Y.
        • Luo J.-C.
        • et al.
        Efficacies of genotypic resistance-guided vs empirical therapy for refractory helicobacter pylori infection.
        Gastroenterology. 2018; 155: 1109-1119
        • Yu L.
        • Luo L.
        • Long X.
        • et al.
        Susceptibility-guided therapy for Helicobacter pylori infection treatment failures.
        Therap Adv Gastroenterol. 2019; 121756284819874922
        • Cammarota G.
        • Martino A.
        • Pirozzi G.
        • et al.
        High efficacy of 1-week doxycycline- and amoxicillin-based quadruple regimen in a culture-guided, third-line treatment approach for Helicobacter pylori infection.
        Aliment Pharmacol Ther. 2004; 19: 789-795
        • Costa S.
        • Soares J.-B.
        • Gonçalves R.
        Efficacy and tolerability of culture-guided treatment for Helicobacter pylori infection.
        Eur J Gastroenterol Hepatol. 2017; 29: 1258-1263
        • Fiorini G.
        • Vakil N.
        • Zullo A.
        • et al.
        Culture-based selection therapy for patients who did not respond to previous treatment for Helicobacter pylori infection.
        Clin Gastroenterol Hepatol. 2013; 11: 507-510
        • Gasbarrini A.
        • Ojetti V.
        • Armuzzi A.
        • et al.
        Efficacy of a multistep strategy for Helicobacter pylori eradication.
        Aliment Pharmacol Ther. 2000; 14: 79-83
        • Tay C.Y.
        • Windsor H.M.
        • Thirriot F.
        • et al.
        Helicobacter pylori eradication in Western Australia using novel quadruple therapy combinations.
        Aliment Pharmacol Ther. 2012; 36: 1076-1083
        • Vicente R.
        • Sicilia B.
        • Gallego S.
        • et al.
        Helicobacter pylori eradication in patients with peptic ulcer after two treatment failures: a prospective culture-guided study.
        Gastroenterol Hepatol. 2002; 25: 438-442
        • Yahav J.
        • Samra Z.
        • Niv Y.
        • et al.
        Susceptibility-guided vs. empiric retreatment of Helicobacter pylori infection after treatment failure.
        Dig Dis Sci. 2006; 51: 2316-2321
        • López-Góngora S.
        • Puig I.
        • Calvet X.
        • et al.
        Systematic review and meta-analysis: susceptibility-guided versus empirical antibiotic treatment for Helicobacter pylori infection.
        J Antimicrob Chemother. 2015; 70: 2447-2455
        • Miehlke S.
        • Hansky K.
        • Schneider-Brachert W.
        • et al.
        Randomized trial of rifabutin-based triple therapy and high-dose dual therapy for rescue treatment of Helicobacter pylori resistant to both metronidazole and clarithromycin.
        Aliment Pharmacol Ther. 2006; 24: 395-403
        • Gao C.P.
        • Zhou Z.
        • Wang J.Z.
        • et al.
        Efficacy and safety of high-dose dual therapy for Helicobacter pylori rescue therapy: a systematic review and meta-analysis.
        J Dig Dis. 2016; 17: 811-819
        • Yang X.
        • Wang J.-X.
        • Han S.-X.
        • et al.
        High dose dual therapy versus bismuth quadruple therapy for Helicobacter pylori eradication treatment: a systematic review and meta-analysis.
        Medicine (Baltimore). 2019; 98: e14396
        • Nyssen O.P.
        • Perez-Aisa A.
        • Castro-Fernandez M.
        • et al.
        European Registry on Helicobacter pylori management: single-capsule bismuth quadruple therapy is effective in real-world clinical practice.
        United Eur Gastroenterol J. 2021; 9: 38-46
        • Fiorini G.
        • Zullo A.
        • Vakil N.
        • et al.
        Rifabutin triple therapy is effective in patients with multidrug-resistant strains of Helicobacter pylori.
        J Clin Gastroenterol. 2018; 52: 137-140
        • Fiorini G.
        • Saracino I.M.
        • Zullo A.
        • et al.
        Rescue therapy with bismuth quadruple regimen in patients with Helicobacter pylori -resistant strains.
        Helicobacter. 2017; : 22
        • Saracino I.M.
        • Pavoni M.
        • Zullo A.
        • et al.
        Antibiotic resistance and therapy outcome in H. pylori eradication failure patients.
        Antibiotics (Basel). 2020; 9: E121
        • Patel A.
        • Shah N.
        • Prajapati J.B.
        Clinical application of probiotics in the treatment of Helicobacter pylori infection – a brief review.
        J Microbiol Immunol Infect. 2014; 47: 429-437
        • McFarland L.V.
        • Huang Y.
        • Wang L.
        • et al.
        Systematic review and meta-analysis: multi-strain probiotics as adjunct therapy for Helicobacter pylori eradication and prevention of adverse events.
        United Eur Gastroenterol J. 2016; 4: 546-561