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PCR detection of Helicobacter pylori infection in gastric biopsies allows the detection of this bacterium and the mutations associated with macrolide resistance. The aim of this study was to evaluate the performance of RIDA®GENE H. pylori PCR (r-Biopharm) on the ELITe InGenius System (Elitech). Two hundred gastric biopsies were obtained. These biopsies were ground in nutrient broth. Two hundred microliters of this suspension was treated with proteinase K, and then, 200 µL was transferred to an ELITe InGenius sample tube and tested using RIDA®GENE H. pylori PCR reagents. In-house H. pylori PCR was used as a reference. The sensitivity of RIDA®GENE H. pylori PCR with ELITe InGenius was 100%, the specificity was 98% (95% confidence interval (CI), 95.3–100%), the PPV was 98% (95% CI, 95.3–100%), and the NPV was 100% for the detection of H. pylori. All of these parameters were 100% for the categorization of macrolide resistance. The adaptation of RIDA®GENE H. pylori PCR reagents on the ELITe InGenius System was successful. This PCR is easy to use on this system.

Background Cancer stem cells (CSCs) are at the origin of tumour initiation and progression in gastric adenocarcinoma (GC). However, markers of metastasis-initiating cells remain unidentified in GC. In this study, we characterized CD44 variants expressed in GC and evaluated the tumorigenic and metastatic properties of CD44v3+ cells and their clinical significance in GC patients. Methods Using GC cell lines and patient-derived xenografts, we evaluated CD44+ and CD44v3+ GC cells molecular signature and their tumorigenic, chemoresistance, invasive and metastatic properties, and expression in patients-derived tissues. Results CD44v3+ cells, which represented a subpopulation of CD44+ cells, were detected in advanced preneoplastic lesions and presented CSCs chemoresistance and tumorigenic properties in vitro and in vivo. Molecular and functional analyses revealed two subpopulations of gastric CSCs: CD44v3+ CSCs with an epithelial-mesenchymal transition (EMT)-like signature, and CD44+/v3– CSCs with an epithelial-like signature; both were tumorigenic but CD44v3+ cells showed higher invasive and metastatic properties in vivo. CD44v3+ cells detected in the primary tumours of GC patients were associated with a worse prognosis. Conclusion CD44v3 is a marker of a subpopulation of CSCs with metastatic properties in GC. The identification of metastasis-initiating cells in GC represents a major advance for further development of anti-metastatic therapeutic strategies.

PCR detection of Helicobacter pylori infection in gastric biopsies allows the detection of this bacterium and the mutations associated with macrolide resistance. The aim of this study was to evaluate the performance of RIDA®GENE H. pylori PCR (r-Biopharm) on a BD MAX™ System (Becton Dickinson). Two hundred ten gastric biopsies obtained were included. These biopsies were ground in nutrient broth. Two hundred microliters of this suspension was treated with proteinase K; 200 µL was transferred to a BD MAX™ sample tube then tested using RIDA®GENE H. pylori PCR reagents. In-house H. pylori PCR was used as a reference. The sensitivity of RIDA®GENE H. pylori PCR with BD MAX™ was 100%, the specificity was 99.08% (95% confidence interval (CI), 97.21-100%), the PPV was 99.02% (95% CI, 97.09-100%), and the NPV was 100% for the detection of H. pylori. The sensitivity was 97.14% (95% CI, 93.87-100%), the specificity was 100%, the PPV was 100%, and the NPV was 98.48% (95% CI, 96.08-100%) for categorization of macrolides resistance. The adaptation of RIDA®GENE H. pylori PCR on the BD MAX™ System is of considerable interest for microbiologists who seek to establish this assay in their laboratories.

The discovery of Helicobacter pylori in 1982 drew to an end the stomach being considered as a sterile organ. Later, the progress in molecular methods, especially Next Generation Sequencing and metagenomics, has highlighted the fact that a diverse microbiota including five major phyla could also be present in the stomach. However, when present, H. pylori is the essential species and it influences the other bacterial communities in terms of richness and evenness. It is now well accepted that H. pylori is the main risk factor for gastric cancer, especially the strains harboring the cag pathogenicity island and the CagA oncoprotein, but the need for other factors from the host and the environment can explain the important difference between those infected and those developing gastric cancer. Several studies showed a difference between the gastric microbiota of patients at various stages of development of gastric premalignant and malignant lesions, showing globally a reduced microbial diversity and an increase in the presence of intestinal commensals, especially with nitrosative functions. Other studies showed an increase in oral microbiota. These data suggest that the gastric microbiota other than H. pylori may play a role in the last steps of gastric carcinogenesis. It must also be noted that in a limited number of cases, a virus: the Epstein Barr Virus is responsible for the evolution toward gastric cancer, while in others the mycobiota also needs to be explored. Finally, the use of mice models allowed an exploration of the role of different gastric microbiota in addition to H. pylori.

BACKGROUND AND OBJECTIVES The present study describes the successful adaptation of an in-house Polymerase Chain Reaction (PCR) for Helicobacter pylori detection coupled with the main mutations associated with resistance to clarithromycin in ready-to-use PCR microwell strips. MATERIALS AND METHODS These microwell strips can be used on LightCycler® 480, and are delivered with nine microliters of the reaction mixture dispensed into 8-well microwell strips. An extraction control PCR targeting the β-globin household gene is amplified in the same run as H pylori detection. RESULTS AND CONCLUSION These microwell strips can be stored at -20°C for 1 year and left at room temperature and in the light for up to 4 h with no impact on the PCR results. Microwell strips can also undergo a thaw and refreeze cycle without impacting the PCR results. These PCR microwell strips are available for purchase from Eurogentec.

Antimicrobial resistance in campylobacters has been described worldwide. The emergence of multiresistant isolates, particularly among Campylobacter coli isolates, is concerning. New resistance mechanisms appear frequently, and DNA-sequence-based methods such as whole-genome sequencing (WGS) have become useful tools to monitor their emergence. The genomes of 51 multiresistant French Campylobacter sp. clinical strains from 2018 to 2019 were analyzed to identify associated resistance mechanisms. Analyses of erythromycin-resistant strains revealed 23S rRNA mutations among most of them and two different methyltransferases in 4 strains: Erm(B) and a novel methyltransferase, named Erm(N) here. The erm(B) gene was found in multidrug-resistant genomic islands, whereas erm(N) was inserted within CRISPR arrays of the CRISPR-cas9 operon. Moreover, using PCR screening in erythromycin-resistant strains from our collection, we show that erm(N) was already present in 3 French clinical strains 2 years before its first report in 2018 in Quebec, Canada. Bacterial transformations confirmed that the insertion of erm(N) into a CRISPR-cas9 operon can confer macrolide resistance. Campylobacter species are easily able to adapt to their environment and acquire new resistance mechanisms, and the emergence of methyltransferases in campylobacters in France is a matter of concern in the coming years.

The diagnosis of Helicobacter pylori infection can be made by using noninvasive tests. The detection of bacterial antigens in stool samples is a technique proposed by some suppliers. The objective of this study was to evaluate retrospectively the performances of the commercially available RIDA®QUICK Helicobacter and RIDASCREEN® Helicobacter (R-Biopharm) kits in detecting H. pylori antigens in stool samples. A collection of 132 stools was used in this study: 94 stools obtained from H. pylori-negative patients and 38 stools from H. pylori-positive patients. The performances (sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV)) were evaluated for the RIDA®QUICK Helicobacter and RIDASCREEN® Helicobacter kits in comparison with real-time PCR results performed on gastric biopsies as well as culture. Discordant results, with respect to H. pylori status, were checked on the same day as the test by repeating the procedure. All of the readings concerning the RIDA®QUICK Helicobacter tests were concordant between 3 users, i.e., 94/94 negative tests and 34/38 positive tests. RIDASCREEN® Helicobacter tests were negative for all 94 H. pylori-negative samples and positive for 35/38 positive stools. Reading of the RIDA®QUICK Helicobacter tests was not a problem in routine practice. The RIDA®QUICK Helicobacter and RIDASCREEN® Helicobacter kits show good performances and can be included in the armamentarium of diagnostic tests for H. pylori infection.

Campylobacter jejuni is the most common cause of bacterial gastroenteritis worldwide. Mainly isolated from stool samples, C. jejuni can also become invasive. C. jejuni belongs to the commensal microbiota of a number of hosts, and infection by this bacterium can sometimes be traced back to exposure to a specific source. Here we genome sequenced 200 clinical isolates (2010–2016) and analyzed them with 701 isolate genomes from human infection, chicken, ruminants and the environment to examine the relative contribution of different reservoirs to non-invasive and invasive infection in France. Host-segregating genetic markers that can discriminate C. jejuni source were used with STRUCTURE software to probabilistically attribute the source of clinical strains. A self-attribution correction step, based upon the accuracy of source apportionment within each potential reservoir, improved attribution accuracy of clinical strains and suggested an important role for ruminant reservoirs in non-invasive infection and a potentially increased contribution of chicken as a source of invasive isolates. Structured sampling of Campylobacter in the clinic and from potential reservoirs provided evidence for variation in the contribution of different infection sources over time and an important role for non-poultry reservoirs in France. This provides a basis for ongoing genomic epidemiology surveillance and targeted interventions.

Metformin is a biguanide molecule used since 1957 to treat type 2 diabetes patients. In addition to its hypoglycemic effects, epidemiological studies have shown that metformin can be associated with a decrease in cancer development risk in diabetic populations. Thus, since 2005 this molecule is largely studied for its antitumoural properties in different types of cancer. The potential antitumoural effect of metformin in gastric cancer has been poorly studied. Here, we detailed the different described mechanisms implicated in the antitumoural effect of metformin in gastric cancer, from the signalling pathways to the functional effects on gastric cancer cell lines and gastric cancer stem cells.

BACKGROUND & AIMS: The decline in Helicobacter pylori cure rates emphasizes the need for readily available methods to determine antimicrobial susceptibility. Our aim was to compare targeted next-generation sequencing (NGS) and culture-based H pylori susceptibility testing using clinical isolates and paired formalin-fixed, paraffin-embedded (FFPE) gastric biopsies. METHODS: H pylori isolates and FFPE tissues were tested for susceptibility to amoxicillin, clarithromycin, metronidazole, levofloxacin, tetracycline, and rifabutin using agar dilution and NGS targeted to 23S rRNA, gyrA, 16S rRNA, pbp1, rpoB and rdxA. Agreement was quantified using k statistics. RESULTS: Paired comparisons included 170 isolates and FFPE tissue for amoxicillin, clarithromycin, metronidazole, and rifabutin and 57 isolates and FFPE tissue for levofloxacin and tetracycline. Agreement between agar dilution and NGS from culture isolates was very good for clarithromycin (k = 0.90012), good for levofloxacin (k = 0.78161) and fair for metronidazole (k = 0.55880), and amoxicillin (k = 0.21400). Only 1 isolate was resistant to tetracycline (culture) and 1 to rifabutin (NGS). Comparison of NGS from tissue blocks and agar dilution from isolates from the same stomachs demonstrated good accuracy to predict resistance for clarithromycin (94.1%), amoxicillin (95.9%), metronidazole (77%), levofloxacin (87.7%), and tetracycline (98.2%). Lack of resistance precluded comparisons for tetracycline and rifabutin. CONCLUSIONS: Compared with agar dilution, NGS reliably determined resistance to clarithromycin, levofloxacin, rifabutin, and tetracycline from clinical isolates and formalin-fixed gastric tissue. Consistency was fair for metronidazole and amoxicillin. Culture-based testing can predict treatment outcomes with clarithromycin and levofloxacin. Studies are needed to compare the relative ability of both methods to predict treatment outcomes for other antibiotics.

Metformin is widely prescribed to treat type 2 diabetes. Diabetes patients treated with metformin have a decreased risk of cancers, including gastric cancer. Among the factors influencing digestive carcinogenesis, gut microbiota interactions have been intensively studied. Metformin exhibits direct antimicrobial activity toward Helicobacterpylori, which plays a crucial role in gastric carcinogenesis. Mice were infected with H. pylori and treated for 12 days with either metformin or phosphate-buffered saline (PBS) as a control. At the end of the treatment period, the mice were euthanized and cecal and intestinal contents and stool were collected. The gut microbiota of the three different digestive sites (stool, cecal, and intestinal contents) were characterized through 16S RNA gene sequencing. In mice infected with H. pylori, metformin significantly decreased alpha diversity indices and led to significant variation in the relative abundance of some bacterial taxa including Clostridium and Lactobacillus, which were directly inhibited by metformin in vitro. PICRUSt analysis suggested that metformin modifies functional pathway expression, including a decrease in nitrate reducing bacteria in the intestine. Metformin significantly changed the composition and predicted function of the gut microbiota of mice infected with H. pylori, these modifications could be implicated in digestive cancer prevention.

Gastric cancer’s bad incidence, prognosis, cellular and molecular heterogeneity amongst others make this disease a major health issue worldwide. Understanding this affliction is a priority for proper patients’ management and for the development of efficient therapeutical strategies. This review gives an overview of major scientific advances, made during the past 5-years, to improve the comprehension of gastric adenocarcinoma. A focus was made on the different actors of gastric carcinogenesis, including, Helicobacter pylori cancer stem cells, tumour microenvironment and microbiota. New and recent potential biomarkers were assessed as well as emerging therapeutical strategies involving cancer stem cells targeting as well as immunotherapy. Finally, recent experimental models to study this highly complex disease were discussed, highlighting the importance of gastric cancer understanding in the hard-fought struggle against cancer relapse, metastasis and bad prognosis.

Campylobacter spp. enteritis is the most frequent bacterial enteritis in both adults and children and is sometimes a source of severe complications. Its diagnosis by culture suffers from a lack of sensitivity and delays the result, preventing an early initiation of optimal antibiotic therapy in some cases. Our aim was to test a new rapid immuno-enzymatic method for Campylobacter spp. diagnosis in comparison to a composite reference standard (CRS). Stool samples from the French National Reference Center for Campylobacter and Helicobacter were tested with the CAMPYLOBACTER QUIK CHEK™ (Abbott). The CRS used to consider a case positive for Campylobacter spp. was a positive culture and, in case of a negative culture, a positive result obtained with both an ELISA and a molecular test. One hundred and eight stools were included: 53 were positive according to the CRS. If performed alone, culture would have missed 5 cases which the CAMPYLOBACTER QUIK CHEK™ detected. Finally, the CAMPYLOBACTER QUIK CHEK™ showed a sensitivity of 96.2% and a specificity of 94.5% and is relevant for clinical practice. Given the characteristics of the new method, it can be used as a screening method for Campylobacter spp. detection.

Background: The main cause of gastric cancer is the infection by the bacterium Helicobacter pylori which induces a chronic inflammation and an epithelial-to-mesenchymal transition (EMT) leading to the emergence of cells with cancer stem cell (CSC) properties. However, the underlying mechanisms have not been fully characterized. Moreover, H. pylori modulates the host cell autophagic process, but a few studies have investigated the role of this process in tumoral transformation. The aim of this study was to determine whether H. pylori-induced autophagy has a role in CSC emergence. Methods: Autophagic flux in response to H. pylori infection was characterized in AGS cell line expressing the tandem-tagged mCherry-GFP-LC3 protein and using a ratiometric flow cytometry analysis. Then, AGS and MKN45 cell lines were treated with bafilomycin or chloroquine, two pharmaceutical well-known inhibitors of autophagy, and different EMT and CSC characteristics were analyzed. Results: First, a co-expression of the gastric CSC marker CD44 and the autophagic marker LC3 in mice and human stomach tissues infected with H. pylori was observed. Then, we demonstrated in vitro that H. pylori was able to activate the autophagy process with a reduced autophagic flux. Finally, infected cells were treated with autophagy inhibitors, which reduced (i) appearance of mesenchymal phenotypes and migration ability related to EMT and (ii) CD44 expression as well as tumorsphere formation capacities reflecting CSC properties. Conclusion: In conclusion, all these data show that H. pylori-induced autophagy is implicated in gastric CSC emergence and could represent an interesting therapeutic target., This work was supported by the French foundation Ligue contre le Cancer (Pyrénées Atlantiques).

International audience; New imaging techniques are still the topic of many evaluations for both the diagnosis of Helicobacter pylori gastritis and the detection of early gastric cancer. Concerning invasive tests, there were studies on the reuse of the rapid urease test material for other tests, and a novel fluorescent method to be used for histology but with limited sensitivity. Progress occurred essentially in the molecular methods area, especially next‐generation sequencing which is applied to detect both H pylori and the mutations associated with antibiotic resistance. For non‐invasive tests, a few studies have been published on the validity of breath collection bags, the shortening of the testing time, the performance of different analysers or the added value of citric acid in the protocol. The accuracy of serological immunochromatographic tests is also improving. Multiplex serology detecting antibodies to certain proteins allows confirmation of a current infection. Dried blood spots can be used to collect and store blood without a loss of accuracy. Finally, the serum antibody titer can be useful in predicting the risk of gastric cancer. Several stool antigen tests were evaluated with good results, and a novel test using immunomagnetic beads coated with monoclonal antibodies is potentially interesting. PCR detection in stools can also be effective but needs an efficient DNA extraction method. The use of easyMAG® (bioMérieux) combined with Amplidiag® H pylori + ClariR (Mobidiag) appears to be powerful.

International audience; Background and objectives: Surveillance of Helicobacter pylori resistance to antibiotics was carried out in France in 2014, 2016, and 2018. We report here the results of the 2018 survey as well as the evolution over the 5-year period.Materials and methods: In this observational study, gastric biopsies were obtained by 62 gastroenterologists randomly selected in 5 regions of France and sent to a central laboratory where culture, antimicrobial susceptibility testing, and a real-time PCR were performed in order to detect H pylori and its mutations associated with clarithromycin resistance.Results and conclusion: During the year 2018, 951 patients were included: 55.3% women, mean age: 52.4 years ± 15.7, 71.6% born in France. Among them, 359 patients were H pylori positive by both culture and real-time PCR, and 7 more by PCR only. There were 244 naive patients, 110 previously treated patients, and unknown for 5. Primary resistance to clarithromycin was 20.9% [16.3-26.4], to levofloxacin 17.6% [13.4-22.9], and to metronidazole 58.6% [52.3%-64.6%]. Secondary resistance for these antibiotics was 56.4%, 22.7%, and 87.3%, respectively. There was no resistance to amoxicillin and tetracycline and very low resistance to rifampicin (1.2%) in both naive and treated patients. Primary resistance to clarithromycin decreased from 22.2% to 20.3% between 2014 and 2016, and appears to be stable since then. This can be linked to a stable consumption of macrolides over the 3-year time period. Primary levofloxacin resistance was relatively stable while metronidazole resistance increased. Interestingly, in both naive and treated patients, amoxicillin and rifampicin resistance were rare.

Helicobacter pylori infection, the main risk factor for gastric cancer (GC), leads to an epithelial&ndash, mesenchymal transition (EMT) of gastric epithelium contributing to gastric cancer stem cell (CSC) emergence. The Hippo pathway effectors yes-associated protein (YAP) and transcriptional co-activator with PDZ binding motif (TAZ) control cancer initiation and progression in many cancers including GC. Here, we investigated the role of TAZ in the early steps of H. pylori-mediated gastric carcinogenesis. TAZ implication in EMT, invasion, and CSC-related tumorigenic properties were evaluated in three gastric epithelial cell lines infected by H. pylori. We showed that H. pylori infection increased TAZ nuclear expression and transcriptional enhancer TEA domain (TEAD) transcription factors transcriptional activity. Nuclear TAZ and zinc finger E-box-binding homeobox 1 (ZEB1) were co-overexpressed in cells harboring a mesenchymal phenotype in vitro, and in areas of regenerative hyperplasia in gastric mucosa of H. pylori-infected patients and experimentally infected mice, as well as at the invasive front of gastric carcinoma. TAZ silencing reduced ZEB1 expression and EMT phenotype, and strongly inhibited invasion and tumorsphere formation induced by H. pylori. In conclusion, TAZ activation in response to H. pylori infection contributes to H. pylori-induced EMT, invasion, and CSC-like tumorigenic properties. TAZ overexpression in H. pylori-induced pre-neoplastic lesions and in GC could therefore constitute a biomarker of early transformation in gastric carcinogenesis.

Background The diagnosis of Helicobacter pylori infection can be made by PCR on gastric biopsies. The objective of this study was to evaluate retrospectively the performance of the Allplex™ H pylori and ClariR PCR Assay (Seegene). Material and methods A collection of 180 DNA samples extracted from gastric biopsies was used in this study: 90 DNAs from H pylori-negative patients and 90 from H pylori-positive patients. The Allplex™ H pylori and ClariR Assay was performed on a CFX96™ real-time PCR System and analyzed using the Seegene Viewer software. The real-time PCR used as the reference was our in-house H pylori PCR, and discrepant results were tested by the Amplidiag® H pylori + ClariR PCR (Mobidiag). Results The performance of the Allplex™ H pylori and ClariR Assay showed 100% sensitivity, 97.6% specificity, 98% PPV, and 100% NPV. Regarding the detection of H pylori in the 90 expected negative samples, eight late amplifications were obtained (Ct > 39). Six of these eight samples were also positive using the Amplidiag® H pylori + ClariR kit and were therefore considered as true positives. For the two remaining cases, non-pathological evidence of H pylori infection was found. H pylori was detected in all 90 positive samples. Compared with our in-house H pylori PCR, all H pylori WT cases or mutated cases were correctly detected. Conclusions The Allplex™ H pylori and ClariR Assay showed an excellent performance and can be integrated into the armamentarium of diagnostic tests for H pylori infection. This kit has the advantage of differentiating the main mutations associated with macrolide resistance.

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.

In the absence of perfect reference standard, classical techniques result in biased diagnostic accuracy and prevalence estimates. By statistically defining the true disease status, latent class models (LCM) constitute a promising alternative. However, LCM is a complex method which relies on parametric assumptions, including usually a conditional independence between tests and might suffer from data sparseness. We carefully applied LCMs to assess new campylobacter infection detection tests for which bacteriological culture is an imperfect reference standard. Five diagnostic tests (culture, polymerase chain reaction and three immunoenzymatic tests) of campylobacter infection were collected in 623 patients from Bordeaux and Lyon Hospitals, France. Their diagnostic accuracy were estimated with standard and extended LCMs with a thorough examination of models goodness-of-fit. The model including a residual dependence specific to the immunoenzymatic tests best complied with LCM assumptions. Asymptotic results of goodness-of-fit statistics were substantially impaired by data sparseness and empirical distributions were preferred. Results confirmed moderate sensitivity of the culture and high performances of immunoenzymatic tests. LCMs can be used to estimate diagnostic tests accuracy in the absence of perfect reference standard. However, their implementation and assessment require specific attention due to data sparseness and limitations of existing software.

Introduction La connaissance de la sensibilite aux antibiotiques qui evolue dans le temps est un element essentiel dans la prise en charge de l’infection a Helicobacter pylori. Le but de cette etude a ete de determiner la sensibilite aux principaux antibiotiques utilises pour cette infection en 2018 en France et de la comparer a celle observee dans deux etudes precedentes (2014 et 2016) menees selon le meme protocole. Materiels et methodes Il s’agit d’une etude observationnelle multicentrique. Des gastro-enterologues selectionnes au hasard dans 5 grandes regions metropolitaines ont recrute des patients adultes (maximum 1000) necessitant une fibroscopie. Les biopsies (antre et fundus) etaient transportees a 4 °C et traitees au CNR des Helicobacters. Apres broyage la culture etait realisee sur 2 milieux selectifs incubes a 37 ° C en atmosphere micro-aerobie durant un maximum de 10 jours. Les tests d’identification etaient pratiques sur les colonies suspectes ainsi qu’un antibiogramme par Etest (clarithromycine, levofloxacine, metronidazole, amoxicilline) ou disque (tetracycline, rifampicine). En parallele, un PCR en temps reel maison ciblant l’ADNr 23S etait effectuee pour detecter H. pylori et les eventuelles mutations associees a la clarithromycine. Resultats Finalement, 62 medecins ont ete recrutes et ont inclus 951 patients : hommes 44,7 %, âge moyen 52,4 ans et 79,5 % nes en Europe. H. pylori a ete detecte chez 359 par culture (37,7 %) et sept de plus par PCR. Parmi ces 366 cas positifs, 248 n’avaient jamais recu de traitement d’eradication. Le taux de resistance a la clarithromycine pour ces 248 etait de 20,9 %, proche de celui de 2016 (20,3 %) mais inferieur a celui de 2014 (22,2 %). En revanche, la resistance a la levofloxacine est en legere augmentation (15,4 %, 14,7 % et 17,6 %, respectivement en 2014, 2016 et 2018), ainsi que celle au metronidazole (45,9 %, 54,2 % et 58,6 %). Les cas de resistance a l’amoxicilline et a la rifampicine sont restes inferieurs ou proches de 1 % et aucune resistance a la tetracycline n’a ete observee, ni d’ailleurs chez les malades ayant eu un echec du Pylera®. Conclusion En conclusion, on observe une stabilisation de la resistance a la clarithromycine aux environs de 20 %, ce qui justifie la necessite de tester cet antibiotique avant de l’utiliser. La resistance a la levofloxacine est en legere augmentation et au metronidazole en nette augmentation. Une quasi absence de resistance est notee pour les autres antibiotiques. La strategie proposee par l’HAS de tester la sensibilite a la clarithromycine avant de prescrire une triple therapie contenant cet antibiotique est pleinement justifiee, d’autant qu’il existe des tests moleculaires disponibles dans ce but.

Campylobacter enteritis is the most frequent bacterial enteritis including in children. Its diagnosis suffers from the lack of sensitivity and delayed result of culture. Our aim was to test a new PCR-derived method for Campylobacter diagnosis in comparison to a composite reference. Patients presenting to the emergency ward of our hospital with enteric symptoms during the 2016 summer season were included. In addition to culture, an ELISA and an in-house real-time PCR were performed, as well as the new method (Orion GenRead Campylobacter) on all stool specimens. The composite reference used to consider a case positive for Campylobacter was either culture positive and in case of negative culture both the ELISA and real-time PCR positive. One hundred fifty patients were included, 64 being infants or children. There were 29 cases positive by the composite reference, with 19 of the 64 children (29.7%) and 10 of the 86 adults (11.6%). If performed alone, culture would have missed six cases. The Orion GenRead Campylobacter detected all the positives by the composite reference but also 12 cases negative by the composite reference (sensitivity 100%, specificity 90.1%). Given the characteristics of the new method, it can be used as a screening method for Campylobacter detection.

The aim of this study was to evaluate, using two independent polymerase chain reaction (PCR) formats, the results of Campylobacter detection by the BD MAXTM Enteric Bacterial Panel PCR (Becton Dickinson, Le Pont de Claix, France) in the absence of positive culture. A total of 77 samples found positive for Campylobacter on BD MAXTM but negative by culture were studied. Upon reception, one in-house real-time-PCR for Campylobacter sp. and a PCR with the RIDAGENE Bacterial Stool Panel (r-biopharm, Darmstadt, Germany) were performed. The data obtained using these two PCR formats were evaluated with respect to the cycle threshold (Ct) and fluorescence intensity values (FI) obtained on BD MAXTM. Ct and FI values were also obtained for 80 positive Campylobacter cases by culture. Among the 77 samples, 33 were positive with the two PCRs, and 37 remained negative. For the 33 double-positive PCRs samples, the Ct values obtained on BD MAXTM were lower than 30 in 93.9%, and FI > 2000 for 97% of cases. For the 37 double-negative PCRs samples, the Ct values obtained on BD MAXTM were 2000 for 40.5% of cases. Positive culture cases had Ct values < 30 in 96.2% and FI > 2000 in 98.8%. We showed that the Ct values obtained on BD MAXTM can help to interpret the results. Almost 96% of the Campylobacter sp. cases detected by culture or with the two reference PCRs positive showed a Ct value on BD MAXTM, meaning that stools detected as positive with BD MAXTM and having a Ct > 30 may be false positives.

International audience; Endoscopic imaging of the stomach is improving. In addition to narrow band imaging, other methods, for example, blue light imaging and linked color imaging, are now available and can be combined with artificial intelligence systems to obtain information on the gastric mucosa and detect early gastric cancer. Immunohistochemistry is only recommended as an ancillary stain in case of chronic active gastritis without Helicobacter pylori detection by standard staining, and recommendations to exclude false negative H. pylori results have been made. Molecular methods using real-time PCR, droplet digital PCR, or amplification refractory mutation system PCR have shown a high accuracy, both for detecting H. pylori and for clarithromycin susceptibility testing, and can now be used in clinical practice for targeted therapy. The most reliable non-invasive test remains the 13 C-urea breath test. Large data sets show that DOB values are higher in women and that the cut-off for positivity could be decreased to 2.74 DOB. Stool antigen tests using monoclonal antibodies are widely used and may be a good alternative to UBT, particularly in countries with a high prevalence of H. pylori infection. Attempts to improve serology by looking at specific immunodominant antigens to distinguish current and past infection have been made. The interest of Gastropanel® which also tests pepsinogen levels was confirmed.

International audience; Helicobacter pylori infection is responsible for gastric carcinogenesis but host factors are also implicated. IQGAP1, a scaffolding protein of the adherens junctions interacting with E-cadherin, regulates cellular plasticity and proliferation. In mice, IQGAP1 deficiency leads to gastric hyperplasia. The aim of this study was to elucidate the consequences of IQGAP1 deletion on H. pylori-induced gastric carcinogenesis.Transgenic mice deleted for iqgap1 and WT littermates were infected with Helicobacter sp., and histopathological analyses of the gastric mucosa were performed. IQGAP1 and E-cadherin expression was evaluated in gastric tissues and in gastric epithelial cell lines in response to H. pylori infection. The consequences of IQGAP1 deletion on gastric epithelial cell behaviour and on the acquisition of cancer stem cell (CSC)-like properties were evaluated. After one year of infection, iqgap1+/- mice developed more preneoplastic lesions and up to 8 times more gastro-intestinal neoplasia (GIN) than WT littermates. H. pylori infection induced IQGAP1 and E-cadherin delocalization from cell-cell junctions. In vitro, knock-down of IQGAP1 favoured the acquisition of a mesenchymal phenotype and CSC-like properties induced by H. pylori infection.Our results indicate that alterations in IQGAP1 signalling promote the emergence of CSCs and gastric adenocarcinoma development in the context of an H. pylori infection.

Aim: Helicobacter pylori infection is a worldwide infection, its eradication rates with conventional therapies have fallen to unacceptable levels. In this context we were interested in metformin, to determine its effect on H. pylori growth. Materials & methods: Antimicrobial susceptibility tests and survival curves were performed in vitro and a H. pylori-infected mice model was used to determine metformin effect in vivo. Results: Helicobacter pylori survival and growth were decreased in presence of metformin. Furthermore, metformin-treated mice had significantly less bacteria in their stomach than the untreated mice. Conclusion: Our work is the first to demonstrate a direct antimicrobial effect of metformin on H. pylori, indicating that this molecule has not yet revealed its full potential.

The detection of campylobacters in stools is performed essentially by culture, but this technique has a low sensitivity. New detection methods are now available. Among them, immunochromatography tests (ICTs) are very attractive in that they offer a result within 15 min. However, previous studies suggest that these tests have a relatively low specificity. The objective of this study was to evaluate the performance of these tests. During the study period, all patients who consulted the emergency units and had a stool culture were included. Their stool samples were tested with two ICTs, Ridaquick Campylobacter and Immuno Card STAT! Campy. Stools were also tested by a home-made PCR and two commercially available enzyme-linked immunosorbent assays (ELISAs) when one of the ICTs was positive. The composite reference standard (CRS) was defined as positive if the culture was positive or, in case of a negative culture, if the PCR and one of the ELISAs were positive simultaneously. Three hundred and five patients were included. Among the 50 positive specimens with Ridaquick Campylobacter, 47 were considered true positives by the CRS, corresponding to a positive predictive value (PPV) of 94.0%. Among the 52 positive specimens with Immuno Card STAT! Campy, 44 were considered true positives by the CRS, corresponding to a PPV of 84.6%. The negative predictive values were estimated at 94.9 and 92.4% for the Ridaquick Campylobacter and Immuno Card STAT! Campy tests, respectively. ICTs appear to be very efficient and allow a very rapid detection of campylobacters, which is important for treating early campylobacter infections with an adapted antibiotherapy.

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-Iβ. 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.

International audience; Gastric cancer is the third leading cause of cancer-related deaths worldwide and has still a poor prognosis. Therefore, new therapeutic strategies are needed: among them, targeting cancer stem cells (CSCs) could offer new opportunities. The aim of our study was to evaluate the anti-tumoural effect of metformin on gastric cancer in vitro and in vivo and especially, to determine whether this molecule could target the gastric CSCs. Metformin effects were evaluated on the proliferation and tumourigenic properties of the gastric CSCs from patient-derived primary tumour xenografts (PDXs) and cancer cell lines (MKN45, AGS and MKN74) in vitro in conventional 2 dimensional (2D) and in 3 dimensional (3D) culture systems, in which only CSCs are able to form tumourspheres and in mouse xenograft models in vivo. Metformin induced a cell cycle arrest, which decreased cell proliferation in the 2D cultures. In a 3D culture system, metformin decreased the number of tumourspheres, revealing its capacity to target the CSCs. This effect was confirmed by the study of the expression of CSC markers (CD44 and Sox2) and differentiation markers (Kruppel-like factor 4 and MUC5AC), which were decreased or increased in response to metformin, respectively. Finally, in vivo treatment of PDXs with metformin led to a tumour growth delay and decreased the self-renewal ability of the CSCs. These results suggest that the use of metformin could represent an efficient strategy to inhibit tumour growth by targeting gastric CSCs.

Important progress is being made in endoscopic methods which allow clinicians to predict the presence of Helicobacter pylori based on characteristics of gastric mucosa and to obtain targeted biopsies. There are also important developments in molecular methods with various techniques derived from standard PCR, applied both on gastric biopsies and stool specimens. Progress is being made in microfluidic systems to get a reliable diagnosis in a very short time. The interest of the

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.

The aim of this study was to evaluate, using two independent polymerase chain reaction (PCR) formats, the results of Campylobacter detection by the BD MAXTM Enteric Bacterial Panel PCR (Becton Dickinson, Le Pont de Claix, France) in the absence of positive culture. A total of 77 samples found positive for Campylobacter on BD MAXTM but negative by culture were studied. Upon reception, one in-house real-time-PCR for Campylobacter sp. and a PCR with the RIDAGENE Bacterial Stool Panel (r-biopharm, Darmstadt, Germany) were performed. The data obtained using these two PCR formats were evaluated with respect to the cycle threshold (Ct) and fluorescence intensity values (FI) obtained on BD MAXTM. Ct and FI values were also obtained for 80 positive Campylobacter cases by culture. Among the 77 samples, 33 were positive with the two PCRs, and 37 remained negative. For the 33 double-positive PCRs samples, the Ct values obtained on BD MAXTM were lower than 30 in 93.9%, and FI &gt, 2000 for 97% of cases. For the 37 double-negative PCRs samples, the Ct values obtained on BD MAXTM were &lt, 30 in only 18.9%, however FI were &gt, 2000 for 40.5% of cases. Positive culture cases had Ct values &lt, 30 in 96.2% and FI &gt, 2000 in 98.8%. We showed that the Ct values obtained on BD MAXTM can help to interpret the results. Almost 96% of the Campylobacter sp. cases detected by culture or with the two reference PCRs positive showed a Ct value on BD MAXTM, meaning that stools detected as positive with BD MAXTM and having a Ct &gt, 30 may be false positives.

La spectrometrie de masse MALDI-TOF (Matrix-Assisted Laser Desorption Ionization Time-Of-Flight) se positionne comme l’outil essentiel d’un futur proche pour l’identification bacterienne. Il etait donc indispensable d’evaluer ses performances reelles en routine dans un laboratoire de bacteriologie.

Campylobacter species, especially Campylobacter jejuni and Campylobacter coli , are a major cause of human bacterial enteritis. Current detection in stools is done essentially by culture on selective and nonselective media with filtration. These methods were compared to 2 molecular biology methods, an in-house real-time PCR and a multiplex PCR named Seeplex Diarrhea ACE Detection, and 3 immunoenzymatic methods, Premier Campy, RidaScreen Campylobacter, and ImmunoCard Stat!Campy. Out of 242 stool specimens tested, 23 (9.5%) fulfilled the positivity criteria, i.e., they were positive by one or both culture methods or, in case of a negative culture, by a positive molecular method and a positive immunoenzymatic method. The striking feature of this study is the low sensitivity of culture, in the range of 60%, in contrast to immunoenzymatic and molecular tests.

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.

A large database of Campylobacter isolates precisely identified at the species level was used to compare patients' characteristics. In a multivariate analysis, Campylobacter coli was found more often in older patients and in patients having traveled abroad and less often in summertime than Campylobacter jejuni . Campylobacter fetus infection occurred in much older patients and in hospitalized patients with a systemic disease.

This note reports an interesting way to rapidly identify bacteria grown from blood culture bottles. Chocolate agar plates were inoculated with 1 drop of the positive blood bottle medium. After a 3-hour incubation, the growth veil was submitted to MALDI-TOF mass spectrometry: 77% of the bacteria present have been correctly identified.

Helicobacter pylori is a Gram-negative, microaerophilic bacterium which colonises human gastric mucosa. Initially, B. Marshall and W. Warren discovered the etiological role of H. pylori in gastritis and peptic ulcers and received the Nobel Prize in Medicine in 2005. Indeed, since 1994, H. pylori has been also recognised by the WHO to be associated with gastric cancer, being the first cause of gastric adenocarcinoma based on epidemiological data and Hill’s criteria for causality. H. pylori infection is responsible for at least 90 % of non-cardia gastric cancers and is the third cause of mortality by cancer in the world with nearly one million new cases per year.