Introduction: Antibiotic resistance is the main factor that affects the effi cacy of current therapeutic regimens against Helicobacter pylori. This study aimed to determine the rates of resistance to effi cacy clarithromycin, amoxicillin, tetracycline, levofl oxacin and metronidazole among H. pylori strains isolated from Turkish patients with dyspepsia. Methods: H. pylori was cultured from corpus and antrum biopsies that were collected from patients with dyspeptic symptoms, and the antimicrobial susceptibility of H. pylori was determined using the E-test (clarithromycin, amoxicillin, tetracycline, metronidazole and levofl oxacin) according to the EUCAST breakpoints. Point mutations in the 23S rRNA gene of clarithromycin-resistant strains were investigated using realtime PCR. Results: A total of 98 H. pylori strains were isolated, all of which were susceptible to amoxicillin and tetracycline. Of these strains, 36.7% (36/98) were resistant to clarithromycin, 35.5% (34/98) were resistant to metronidazole, and 29.5% (29/98) were resistant to levofl oxacin. Multiple resistance was detected in 19.3% of the isolates. The A2143G and A2144G point mutations in the 23S rRNA-encoding gene were found in all 36 (100%) of the clarithromycin-resistant strains. Additionally, the levofl oxacin MIC values increased to 32 mg/L in our H. pylori strains. Finally, among the clarithromycin-resistant strains, 27.2% were resistant to levofl oxacin, and 45.4% were resistant to metronidazole. Conclusions: We conclude that treatment failure after clarithromycin-or levofl oxacinbased triple therapy is not surprising and that metronidazole is not a reliable agent for the eradication of H. pylori infection in Turkey.

The Helicobacter pylori cagA gene is a major virulence factor that plays an important role in gastric pathologies. DNA sequence data for the cagA 39 region of Western isolates differ markedly in their EPIYA motifs from those of East Asian isolates. An increase in the number of these motifs is known to be associated with gastric cancer. Whether such an association is also the case for peptic ulceration was investigated in this study. Gastric biopsies were collected from 96 patients with duodenal ulcer (DU), gastric ulcer (GU) and gastritis. The types of EPIYA motif detected by PCR among 28 DU strains were 13 ABC, eight ABCC, six ABCCC, and in one patient both ABC and ABCCCCC; among nine GU strains were two ABC, five ABCC and two ABCCC; and among 40 gastritis strains were 35 ABC and five ABCC. DNA sequencing was carried out to confirm the detection of the EPIYA motif types and to analyse their peptide sequences. A significant association was found between the number of the EPIYA-C motifs (¢2) and peptic ulceration (P50.00001) compared with gastritis. In conclusion, this study shows that our patients harboured cagA-positive H. pylori strains with EPIYA motifs of the Western type and that the increase in the number of EPIYA-C motifs was significantly associated with DU and GU but not with gastritis, indicating predictive association with the severity of the disease. INTRODUCTIONHelicobacter pylori is the causative agent of gastritis and peptic ulcers and plays an important role in the development of gastric cancer. The severity of disease outcome has been attributed to possession of the cag pathogenicity island, which encodes a type IV secretory system that facilitates translocation of the CagA protein (Backert et al., 2004). This protein plays an important role in the aetiology of H. pylori-induced gastric pathologies. When CagA is secreted into gastric epithelial cells, some CagA molecules are tyrosine-phosphorylated through their EPIYA motifs, whilst other CagA molecules remain unphosphorylated (Poppe et al., 2007; Selbach et al., 2003; Stein et al., 2002). Phosphorylated CagA causes dysregulation of the epithelial structure through its effect on the signal system of the host cell (Brandt et al., 2005), whilst unphosphorylated CagA also contributes to the development of H. pylori-associated gastric diseases, including gastric cancer (El-Etr et al., 2004;Hirata et al., 2002). Recently, Suzuki et al. (2009) reported that a conserved motif in the C-terminal region of CagA, distinct from the EPIYA motifs and designated CRPIA (conserved repeat responsible for phosphorylation-independent activity), plays a pivotal role in H. pylori pathogenesis. The size variation of the CagA protein has been shown to be related to the presence of the repeat sequences containing the EPIYA motifs within the 39 variable ends (Argent et al., 2005). H. pylori strains isolated in Western countries contain the EPIYA-A, EPIYA-B and Western cagA-specific EPIYA-C segments. The latter motif varies in number among distinct Western CagA proteins,...

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Helicobacter pylori cagPAI genes play an important role in pathogenesis, however little is known about their functions in isolates from Turkish patients. We aimed to evaluate the intactness and the effect of the cagPAI genes (cagT, cagM, cagE, cagA) and cagA EPIYA motifs on the AGS morphological changes and IL-8 induction. Of 53 patients 38 were found infected with H. pylori. PCR amplification of the cagPAI genes showed 42.1 % intact, 39.5 % partially deleted and 18.4 % with complete deletions. Isolates from gastritis, duodenal and gastric ulcer patients with intact and partially deleted cagPAI genes induced higher IL-8 secretion than those with complete deletions. Isolates from gastritis patients had higher deletion frequencies of the cagT and cagM genes than the other two genes. Infection of AGS cells with isolates that possess intact cagPAI and EPIYA-ABC resulted in the formation of the hummingbird phenotype. The cagA positive isolates induced higher IL-8 secretion than cagA negative isolates. Isolates from DU patients with more than one EPIYA-C motif induced higher concentrations of IL-8 than those with EPIYA-ABC. In conclusion, the intactness of the cagPAI in our isolates from different patients was not conserved. An intact cagPAI was found to play an important role in the pathogenesis of DU but not GU or gastritis. The cagA gene, but not other cagPAI genes, was associated with the induction of IL-8 and the morphological changes of the AGS cells. An increase in the number of EPIYA-C motifs had noticeable effect on the formation of the hummingbird phenotype.

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