[Effectiveness of empirical Helicobacter pylori eradication therapy with furazolidone in Russia: results from the European Registry on Helicobacter pylori Management (Hp-EuReg)].

BACKGROUND: First-line therapy does not always provide a high level of Helicobacter pylori eradication due to the increase of H. pylori resistance to antibiotics; therefore, it remains necessary to identify the most effective rescue treatments. The purpose of this study was to evaluate the efficacy and safety of empirical H. pylori furazolidone-containing regimens. MATERIALS AND METHODS: Adult H. pylori infected patients empirically treated with furazolidone-containing eradication regimens were registered in an international, prospective, multicenter non-intervention European registry on H. pylori management (Hp-EuReg). Data were collected at AEG-REDCap e-CRF from 2013 to 2021 and the quality was reviewed. Modified intention-to-treat (mITT) effectiveness analyses were performed. RESULTS: Overall 106 patients received empirical furazolidone-containing therapy in Russia. Furazolidone was prescribed in a sequential scheme along with amoxicillin, clarithromycin and a proton pump inhibitor in 68 (64%) cases, triple regimens were prescribed in 28 (26%) patients and quadruple regimens in 10 (9.4%). Treatment duration of 7 days was assigned to 2 (1.9%) patients, 10-day eradication therapy in case of 80 (75%) and 14 days - in 24 (23%) patients. Furazolidone was mainly used in first- (79%) and second-line (21%) regimens. The methods used to diagnose H. pylori infection were: histology (81%), stool antigen test (64%), 13C-urea breath test (6.6%), and rapid urease test (1.9%). The mITT effectiveness of sequential therapy was 100%; 93% with the triple therapy and 75.5% with quadruple therapy. Compliance was reported in 98% of cases. Adverse events were revealed in 5.7% of patients, mostly nausea (3.8%). No serious adverse events were reported. CONCLUSION: Furazolidone containing eradication regimens appear to be an effective and safe empirical therapy in Russia.

[European Registry on the management of Helicobacter pylori infection: features of diagnosis and treatment in Kazan].

BACKGROUND: As part of an observational multicenter prospective study European Registry on the management of Helicobacter pylori infection, conducted on the initiative of the European H. pylori and Microbiota Study Group, the compliance of clinical practice in the management of patients with Helicobacter pylori infection in Kazan with clinical guidelines was assessed. MATERIALS AND METHODS: The data of 437 patients included into the register by clinical sites in Kazan in 20132019 were analyzed. The methods used for the initial diagnosis of H. pylori infection and eradication control were evaluated. The frequency of various eradication therapy regimens prescription was analyzed in 379 cases. Data regarding the effectiveness of eradication therapy was analyzed in 173 patients. RESULTS: The rapid urease test (44.2% of cases) and cytology/histology (60% of cases) were most often used for the initial diagnosis of H. pylori infection; however non-invasive methods such as 13C-urea breath (9.2%), serology (6.2%), H. pylori stool antigen test (2.3%) were less common. In 21.7% of patients two methods of H. pylori detection were used for primary diagnosis. The control test to evaluate the effectiveness of eradication therapy at the recommended timepoint was performed in 46.2% of patients. 13C-urea breath test (31.7%), stool PCR/stool antigen test (28.7%), rapid urease test (22.3%), cytology/histology (26.2% of cases) prevailed in the assessment of eradication rate. Standard triple therapy, including proton pump inhibitor, clarithromycin and amoxicillin was most commonly prescribed as first-line therapy (64.6% of cases). The duration of eradication therapy was 14 days in the majority of cases with pantoprazole as the most common proton pump inhibitor in standard triple therapy regimens (84.8%). The efficacy of 14-day standard triple therapy (mITT) was 87.0%. CONCLUSION: The results indicate a high frequency of non-invasive methods use for assessing the effectiveness of eradication therapy; however, the overall rate of eradication efficacy assessment is low, limiting the possibility of analyzing the eradication results. The effectiveness of the most common 14-day standard triple first-line therapy in Kazan doesnt reach the recommended 90% eradication level. This could be explained by high rate of pantoprazole use, which is not an optimal proton pump inhibitor in eradication therapy regimens.

[European registry on Helicobacter pylori management (Hp-EuReg) as a tool to evaluate and improve clinical practice in Moscow].

Continuous evaluation of the actual clinical practice of diagnosis and treatment of Helicobacter pylori is crucial in order to provide the best standard of care and to compare health outcomes with expert recommendations. AIM: to evaluate the effectiveness of the standard triple therapy (amoxicillin, clarithromycin, a proton pump inhibitor) and the standard triple therapy plus bismuth tripotassium dicitrate. MATERIALS AND METHODS: Observational, prospective, multicenter study, carried out in one single Russian centre A.S. Loginov Moscow Clinical Scientific Center as part of the Hp-EuReg. Patients were included from 2013 to November 2019 by Russian gastroenterologists. RESULTS: A total of 647 patients were collected and 330 were administered either standard triple therapy ((amoxicillin, clarithromycin, a proton pump inhibitor) or standard triple therapy plus bismuth tripotassium dicitrate. Invasive methods is dominates in the initial diagnosis of H. pylori: the frequency of use of the quick urease test decreased from 50% in 2013 to 31% in 2019. Serology was used in 27.9%. There has been an increase in the use of the13C-urea breath test from 13% in 2013 to 31% in 2019. The histological method (7.5%) and the stool antigen test (3.2%) were used less frequently. For eradication control non-invasive methods are mostly used:13C-UDT (82.7%) and the stool antigen test (14.4%). The effectiveness of standard triple therapy (mITT) was 68% with a 7-day course, 79% with a 10-day course, and 70% with a 14-day course. Combination of bismuth and standard triple therapy eradicates H. pylori (mITT) in 63%, 75% and 89%, respectively. CONCLUSION: An improvement in the clinical practice of managing patients with H. pylori infections has been noted. The standard triple therapy in combination with bismuth tripotassium dicitrate, prescribed for 14 days, is more effective.

Efficacy of a tailored PCR-guided triple therapy in the treatment of Helicobacter pylori infection.

INTRODUCTION: Resistance to clarithromycin and fluoroquinolones is increasing in many countries. We aimed to assess the efficacy of a tailored PCR-guided triple therapy versus an empirical triple therapy in the treatment of H. pylori infection. PATIENTS AND METHODS: French multicenter prospective open-label randomized study to assess H. pylori and resistance to clarithromycin and levofloxacin with GenoType HelicoDR® test. Patients of the control group were treated with empirical therapy of proton pump inhibitor (PPI), amoxicillin, and clarithromycin for 7 days. Patients of the experimental group with clarithromycin-susceptible strains, clarithromycin-resistant/levofloxacin-susceptible strains, and with clarithromycin-resistant/levofloxacin-resistant strains received tailored therapy of PPI, amoxicillin, and clarithromycin for 7 days, PPI, amoxicillin, and levofloxacin for 10 days, and PPI, amoxicillin, and metronidazole for 14 days, respectively. H. pylori eradication was assessed by 13C urea breath test at least 28 days after the end of treatment. RESULTS: We included 526 patients: 260 (49.4%) were randomly assigned to empirical triple therapy and 266 (50.6%) to tailored therapy. Clarithromycin and levofloxacin resistances were 23.3% and 12.8%, respectively. Follow-up urea breath test was available for 415 (78.9%) patients. Tailored therapy was superior to empirical therapy in terms of eradication (85.5% vs. 73.1%, RR=1.85, 95%CI [1.25-2.78], p=0.003). Findings were consistent in the susceptibility analysis using multiple imputation (RR=1.61, 95%CI [1.14-2.27], P=0.003) and per-protocol analysis (RR=1.89, 95%CI [0.25-2.78], p=0.003). CONCLUSION: In a country with a high level of clarithromycin resistance, tailored PCR-guided therapy was superior to empirical triple therapy for H. pylori eradication (https://www.ClinicalTrials.gov: NCT01168063).

[European registry Helicobacter pylori (Hp-EuReg): how has clinical practice changed in Russia from 2013 to 2018 years].

The multicenter prospective observational study initiated by the European Helicobacter and Microbiota Study Group (EHMSG) is conducted in 27 countries in Europe. The data from the Russian part of the European registry for the management of Helicobacter pylori infection (European Registry on the management of Helicobacter pylori infection, protocol: "Hp-EuReg") allows us to analyze the real clinical practice of diagnosis and treatment of H. pylori and compare it with international recommendations. MATERIALS AND METHODS: A comparative analysis of the data entered in the register by the Russian research centers "Hp-EuReg", in the period from 2013 to 2018, was conducted. RESULTS AND DISCUSSION: Invasive diagnostic methods prevail for the primary diagnosis of H. pylori [histology - 20.3% (in 2013 year) - 43.9% (in 2018 year), rapid urease test - 31.7% and 47.8% respectively]. The most popular mode of eradication therapy is a 10-day triple therapy (62.8-76.2%), the effectiveness of which does not exceed 79% (per protocol). Invasive tests (histology) are the leading method for control the effectiveness of therapy, however, there is a tendency towards a wider use of non-invasive methods (H. pylori stool antigen - from 17% in 2013 to 29.3% in 2018 and urea breath test from 6.9 to 18.3%, respectively). Serological test to control the effectiveness of eradication is still used from 8.2% (2013) to 6.1% (2018). Eradication therapy was not performed in 28% of patients throughout the entire observation period. CONCLUSION: In Russia, despite approved domestic and international recommendations, deviations in clinical practice persist, both during eradication therapy and in monitoring the effectiveness of eradication therapy.

Epidemiologic cutoff values to separate wild-type from non-wild-type Campylobacter fetus to ciprofloxacin.

The aim of the present study was to propose epidemiologic cutoffs that could be used in routine practice to separate wild-type from non-wild-type Campylobacter fetus to ciprofloxacin. A total of 123 C. fetus isolates obtained from human samples were used for this purpose. Based on the determination of inhibition zone diameter, minimum inhibitory concentration, and sequencing of the quinolone resistance determining region in the gyraseA gene, for all tested isolates, the following cutoffs were proposed: ciprofloxacin-wild type if the inhibition zone diameter was ≥22 mm or the minimum inhibitory concentration was ≤0.5 mg/L.

Impact of the introduction of a nucleic acid amplification test for Clostridium difficile diagnosis on stool rejection policies.

BACKGROUND: The change from non-molecular to nucleic acid amplification tests (NAATs) is known to increase the detection of Clostridium difficile infection (CDI); however, the impact on stool rejection policies in clinical laboratories is unclear. The current guidelines have reinforced the importance of respecting strict conditions for performing tests on stool samples for CDI diagnosis. The purpose of this study was to estimate whether the implementation of molecular tests has resulted in changes in stool rejection policies between clinical laboratories that introduced NAATs and those that did not. RESULTS: A survey was conducted to evaluate the change in the number of stool samples rejected and the rejection criteria among 12 hospital laboratories in southwestern France before and after the switch from non-molecular tests to NAATs using retrospective data from June 1 till September 30, 2013 and the same period 2014. Four laboratories introduced NAATs as a second or third step in the process. A total of 1378 and 1297 stools samples were collected in 2013 and 2014, respectively. The mean number of rejected stool samples significantly increased (p < 0.001, Chi square test), with a total of 99 (7.1%) and 147 (11.3%) specimens rejected in 2013 and 2014, respectively. Notably, these laboratories had more stringent criteria and were no longer testing the stool samples of patients with CDI-positive results within 7 days. In contrast, there was a significant decrease in the rate of rejected stool samples (p < 0.001, Chi square test) in the five laboratories that did not adopt NAATs and a less stringent stool rejection policy. CONCLUSION: Nucleic acid amplification test implementation improved compliance with recommended stool rejection policies. Laboratories should follow the recommended laboratory algorithm for the CDI diagnosis combined with the correct stool rejection policy.

European Registry on the management of Helicobacter pylori infection (Hp-EuReg): analysis of 2360 patients receiving first-line therapy in Russia.

AIM: European Registry on the management of Helicobacter pylori infection («Hp-EuReg¼) - a multicenter prospective observational study initiated by the European Helicobacter and Microbiota Study Group, conducted in 27 European countries in order to evaluate the real clinical practice of diagnosis and treatment of H. pylori and its comparison with international recommendations. MATERIALS AND METHODS: The analysis of 2360 patients entered in the register by the Russian centres of «Hp-EuReg¼ in 2013-2017, who were underwent 1st line eradication therapy. RESULTS: The most common methods of primary diagnosis of H. pylori are histological (37.7%), rapid urease test (29.2%) and serology (29.7%). The duration of eradication therapy in 9.4% of cases was 7 days, in 65.3% - 10 days, and in 25.3% - 14 days. To control the effec- tiveness of treatment, H. pylori antigen in feces (31.3%), urea breath test (23.4%) and histological method (23.3%) were used. In 3.6% cases was used serology by mistake. In 17.3% of patients control was not carried out. The effectiveness of triple therapy with a PPI, amoxicillin, clar- ithromycin (per protocol) was 67.6%, with 7-day course, 81.1% at 10-day and 86.7% at 14-day course. Eradication rate of triple therapy with addition of bismuth (per protocol) reached 90,6% in the group receiving 10-day scheme and 93.6% in the group receiving the 14-day treatment. CONCLUSION: Significant deviations of clinical practice from expert recommendations, most pronounced at the stage of monitoring the effectiveness of therapy, were noted. The suboptimal efficacy of triple therapy is shown.

Antioxidant activities, anticancer activity and polyphenolics profile, of leaf, fruit and stem extracts of Pistacia lentiscus from Tunisia.

Plant derived compounds have played an important role in the development of several clinically useful anticancer drugs. The aim of the present study was 1) to evaluate for the first time the anti-proliferative activity of a polyphenol enriched extract obtained from leaf, fruit and stem of Tunisian variety of Pistacia lentiscus against two cultured cancer cells, and 2) to carry out a phytochemical analysis of vegetable extracts particularly by determining the chemical composition of phenolics (total polyphenols, flavonoids and condensed tannins content in solvents with varying polarities), 3) to  evaluate the antioxidant activity and identify the major compounds by RP-HPLC. Leaf extract using methanol/water (8:2) showed the highest polyphenol content (124.1 mg GAE/g DW). Moreover, total antioxidant capacity, reducing power and antiradical capacities against DPPH were maximal in leaf extracts with IC50 significantly lower than that standard (BHT). In MTT assay, methanol (8:2) extract exerted the most potent cytotoxic effect. The leaf extract exhibited an important antiproliferative activity (IC50: 135.67 ± 2.5 and 250.45 ± 1.96 µg/ml in CaCo2 and AGS cells respectively) but the infusion extracts of fruit stems and leaves were inactive. The RP-HPLC analysis revealed the presence of several phenolic compounds in P. lentiscus leaf, fruit and stem including tannic acid, gallic acid, digalloyl quinic acid derivative, quercetin and   p-coumaric acid as major phenolics. The high phenolic content and the important antioxidant activities of P. lentiscus extract could be a useful source of natural products and may be increasingly important for human consumption, prevention of damages caused by oxygen free as well as for the agro-food, cosmetic and pharmaceutical industries.

Joint ESPGHAN/NASPGHAN guidelines for the management of helicobacter pylori in children and adolescents (Update 2016)

BACKGROUND: Because of the changing epidemiology of Helicobacter pylori infection and low efficacy of currently recommended therapies, an update of the European Society for Paediatric Gastroenterology Hepatology and Nutrition/North American Society for Pediatric Gastroenterology, Hepatology and Nutrition recommendations for the diagnosis and management of H pylori infection in children and adolescents is required. METHODS: A systematic review of the literature (time period: 2009-2014) was performed. Representatives of both societies evaluated the quality of evidence using GRADE (Grading of Recommendation Assessment, Development, and Evaluation) to formulate recommendations, which were voted upon and finalized using a Delphi process and face-to-face meeting. RESULTS: The consensus group recommended that invasive diagnostic testing for H pylori be performed only when treatment will be offered if tests are positive. To reach the aim of a 90% eradication rate with initial therapy, antibiotics should be tailored according to susceptibility testing. Therapy should be administered for 14 days, emphasizing strict adherence. Clarithromycin-containing regimens should be restricted to children infected with susceptible strains. When antibiotic susceptibility profiles are not known, high-dose triple therapy with proton pump inhibitor, amoxicillin, and metronidazole for 14 days or bismuth-based quadruple therapy is recommended. Success of therapy should be monitored after 4 to 8 weeks by reliable noninvasive tests. CONCLUSIONS: The primary goal of clinical investigation is to identify the cause of upper gastrointestinal symptoms rather than H pylori infection. Therefore, we recommend against a test and treat strategy. Decreasing eradication rates with previously recommended treatments call for changes to first-line therapies and broader availability of culture or molecular-based testing to tailor treatment to the individual child.

Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report.

Important progress has been made in the management of Helicobacter pylori infection and in this fifth edition of the Maastricht Consensus Report, key aspects related to the clinical role of H. pylori were re-evaluated in 2015. In the Maastricht V/Florence Consensus Conference, 43 experts from 24 countries examined new data related to H. pylori in five subdivided workshops: (1) Indications/Associations, (2) Diagnosis, (3) Treatment, (4) Prevention/Public Health, (5) H. pylori and the Gastric Microbiota. The results of the individual workshops were presented to a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in the various clinical scenarios.

Infective endocarditis caused by Streptococcus tigurinus-like organisms.

Streptococcus species are important causes of infective endocarditis but species identification remains challenging. We report two cases of infective endocarditis due to Streptococcus tigurinus-like organisms, which were first identified by 16S ribosomal RNA gene sequence analysis and subsequently confirmed using phylogeny based on the analysis of the shetA gene encoding exfoliative toxin.

The history of Helicobacter pylori: from phylogeography to paleomicrobiology.

The study of the gastric pathogen Helicobacter pylori brought us interesting data on the history of mankind. Based on multi-locus sequence typing, it was possible to trace the migration of Homo sapiens all around the world, and to infer the time when he went Out of Africa. Beside these phylogeographic aspects, paleomicrobiology gave us important information on life in the Neolithic period, following the discovery of Ötzi, the Iceman, who was living in the Tyrolean Alps 5200 years ago, and from whom a Helicobacter pylori genome was sequenced. This review presents the data accumulated in these different fields.

Helicobacter pylori resistance to antibiotics in 2014 in France detected by phenotypic and genotypic methods.

A large survey of antimicrobial resistance of Helicobacter pylori was performed in France in 2014: 984 patients were enrolled by 75 gastroenterologists all over the country. Among the 783 patients who had never received eradication treatment before, 266 (33.9%) were H. pylori positive. The strains showed a high rate of clarithromycin resistance (22.2%), moderate rate of resistance to levofloxacin (15.4%) and high rate of resistance to metronidazole (45.9%). In all, 187 patients had received previous treatment, of which 115 were H. pylori positive with very high resistance to clarithromycin (73.9%) and metronidazole (78.3%). None of the patients receiving PYLERA (Bismuth salt-Tetracycline HCl-Metronidazole) proton-pump inhibitor developed resistance to tetracycline. A real-time PCR applied to gastric biopsy specimens detected all the cases that were positive by culture as well as 30 additional cases. A good correlation was found between the clarithromycin resistance detected by phenotypic methods and the associated mutations for clarithromycin resistance, which has continued to increase in the last decade but at a lower rate than previously observed.

All-trans retinoic acid targets gastric cancer stem cells and inhibits patient-derived gastric carcinoma tumor growth.

Gastric carcinoma is the third leading cause of cancer-related death worldwide. This cancer, most of the time metastatic, is essentially treated by surgery associated with conventional chemotherapy, and has a poor prognosis. The existence of cancer stem cells (CSC) expressing CD44 and a high aldehyde dehydrogenase (ALDH) activity has recently been demonstrated in gastric carcinoma and has opened new perspectives to develop targeted therapy. In this study, we evaluated the effects of all-trans-retinoic acid (ATRA) on CSCs in human gastric carcinoma. ATRA effects were evaluated on the proliferation and tumorigenic properties of gastric carcinoma cells from patient-derived tumors and cell lines in conventional 2D cultures, in 3D culture systems (tumorsphere assay) and in mouse xenograft models. ATRA inhibited both tumorspheres initiation and growth in vitro, which was associated with a cell-cycle arrest through the upregulation of cyclin-dependent kinase (CDK) inhibitors and the downregulation of cell-cycle progression activators. More importantly, ATRA downregulated the expression of the CSC markers CD44 and ALDH as well as stemness genes such as Klf4 and Sox2 and induced differentiation of tumorspheres. Finally, 2 weeks of daily ATRA treatment were sufficient to inhibit gastric tumor progression in vivo, which was associated with a decrease in CD44, ALDH1, Ki67 and PCNA expression in the remaining tumor cells. Administration of ATRA appears to be a potent strategy to efficiently inhibit tumor growth and more importantly to target gastric CSCs in both intestinal and diffuse types of gastric carcinoma.

Dormant phages of Helicobacter pylori reveal distinct populations in Europe.

Prophages of Helicobacter pylori, a bacterium known to co-evolve in the stomach of its human host, were recently identified. However, their role in the diversity of H. pylori strains is unknown. We demonstrate here and for the first time that the diversity of the prophage genes offers the ability to distinguish between European populations, and that H. pylori prophages and their host bacteria share a complex evolutionary history. By comparing the phylogenetic trees of two prophage genes (integrase and holin) and the multilocus sequence typing (MLST)-based data obtained for seven housekeeping genes, we observed that the majority of the strains belong to the same phylogeographic group in both trees. Furthermore, we found that the Bayesian analysis of the population structure of the prophage genes identified two H. pylori European populations, hpNEurope and hpSWEurope, while the MLST sequences identified one European population, hpEurope. The population structure analysis of H. pylori prophages was even more discriminative than the traditional MLST-based method for the European population. Prophages are new players to be considered not only to show the diversity of H. pylori strains but also to more sharply define human populations.

Helicobacter pylori infection and gastric carcinoma.

Helicobacter pylori infection is considered to be the main cause of gastric cancer and the most frequent infection-induced cancer. H. pylori is a heterogeneous species which can harbour pathogenic factors such as a cytotoxin, a pathogenicity island (cag) encoding a type 4 secretion system, and the first bacterial oncoprotein, CagA. This oncoprotein appears to be involved in the carcinogenic process in addition to the inflammation generated. This process may concern either local progenitors via an epithelial-mesenchymal transition, or recruited bone marrow-derived mesenchymal cells. There are also environmental factors such as iron deficiency or high-salt diets which interact with the bacterial factors to increase the risk of gastric cancer as well as genetic polymorphism of certain cytokines, e.g. IL-Iß. Recent data suggest that a break in coevolution of a particular phylogeographic lineage of H. pylori and its usual host may also be a risk factor. Studies are currently being performed to assess the feasibility of organized H. pylori eradication programmes to prevent gastric cancer.

Helicobacter pylori infection and stem cells at the origin of gastric cancer.

Helicobacter pylori infection is now recognized as the main and specific infectious cause of cancer in the world. It is responsible for gastric adenocarcinomas of both intestinal and diffuse types, which are the long-term consequences of the chronic infection of the gastric mucosa. Case-control studies have shown an association between the two, recognized as early as 1994 and further substantiated by interventional studies in which H. pylori eradication has led to the prevention of at least part of the gastric cancers. Experimental studies have highlighted the role of bone marrow-derived cells (BMDCs) and particularly mesenchymal stem cells, in the neoplastic process in about a quarter of the cases and possibly an epithelial-mesenchymal transition (EMT) in the other cases. Different studies have confirmed that chronic infection with H. pylori induces a chronic inflammation and subsequent damage of the gastric epithelial mucosa, leading to BMDC recruitment. Once recruited, these cells home and differentiate by cell-cell fusion with local gastric epithelial cells, bearing local stem cell failure and participating in tissue regeneration. The context of chronic infection and inflammation leads to an EMT and altered tissue regeneration and differentiation from both local epithelial stem cells and BMDC. EMT induces the emergence of CD44+ cells possessing mesenchymal and stem cell properties, resulting in metaplastic and dysplastic lesions to give rise, after additional epigenetic and mutational events, to the emergence of cancer stem cells (CSCs) and adenocarcinoma.

Helicobacter pylori generates cells with cancer stem cell properties via epithelial-mesenchymal transition-like changes.

Helicobacter pylori infection is the major risk factor for gastric adenocarcinoma. The link with gastric adenocarcinoma is partly due to the H. pylori CagA oncoprotein. CagA is responsible for a particular cell phenotype in vitro, the 'hummingbird' phenotype, that corresponds to an elongation of the cells, mimicking an epithelial-mesenchymal transition (EMT). EMT participates in the carcinogenesis process, and is involved in the generation of cancer stem cells (CSCs). However, its involvement in gastric carcinogenesis has yet not been studied. Therefore, the aim of this study was to determine the role of H. pylori in EMT and in the emergence of gastric CSCs. For this purpose, gastric epithelial cells were cocultured with a cagA-positive H. pylori strain or its isogenic-deleted mutants or were transfected with CagA expression vectors. Study of the expression of epithelial and mesenchymal markers showed that H. pylori, via CagA, is responsible for an EMT phenotype associated with an increase in mesenchymal markers as well as CD44 expression, a known gastric CSC marker. Moreover, infection led to an increased ability to migrate, to invade and to form tumorspheres. Cell sorting experiments showed that only the CD44(high) cells induced by H. pylori infection displayed the mesenchymal phenotype and CSC properties in vitro, and had higher tumorigenic properties than CD44(low) cells in xenografted mice. Immunohistochemistry analyses on human and mouse gastric mucosa tissue samples confirmed a high expression of CD44 and mesenchymal markers in H. pylori-infected cases, and in gastric dysplasia and carcinoma. All of these data suggest that H. pylori, via CagA, unveils CSC-like properties by induction of EMT-like changes in gastric epithelial cells.