Management of Antibiotic-Resistant Helicobacter pylori Infection: Perspectives from Vietnam

Antibiotic resistance is the most important factor leading to the failure of eradication regimens. This review focuses on the prevalence of Helicobacter pylori primary and secondary resistance to clarithromycin, metronidazole, amoxicillin, levofloxacin, tetracycline, and multidrug in Vietnam. We searched the PubMed, EMBASE, Vietnamese National Knowledge Infrastructure, and Vietnamese Biomedical databases from January 2000 to December 2016. The search terms included the following: H. pylori infection, antibiotic (including clarithromycin, metronidazole, amoxicillin, levofloxacin, tetracycline, and multidrug) resistance in Vietnam. The data were summarized in an extraction table and analyzed manually. Finally, Excel 2007 software was used to create charts. Ten studies (three studies in English and seven in Vietnamese) were included in this review. A total of 308, 412, 523, 408, 399, and 268 H. pylori strains were included in this review to evaluate the prevalence of H. pylori primary resistance to amoxicillin, clarithromycin, metronidazole, levofloxacin, tetracycline, and multidrug resistance, respectively. Overall, the primary resistance rates of amoxicillin, clarithromycin, metronidazole, levofloxacin, tetracycline, and multidrug resistance were 15.0%, 34.1%, 69.4%, 27.9%, 17.9% and 48.8%, respectively. Secondary resistance rates of amoxicillin, clarithromycin, metronidazole, levofloxacin, tetracycline, and multidrug resistance were 9.5%, 74.9%, 61.5%, 45.7%, 23.5% and 62.3%, respectively. In Vietnam, primary and secondary resistance to H. pylori is increasing over time and affects the effectiveness of H. pylori eradication.

Characterizing Helicobacter pylori cagA in Myanmar

BACKGROUND/AIMS: Differences in the Helicobacter pylori infection rate are not sufficient to clarify the dissimilarity of gastric cancer incidence between Myanmar and its neighboring countries. To better understand this trend, the H. pylori virulence gene cagA was characterized in Myanmar. METHODS: Glutamate-proline-isoleucine-tyrosine-alanine (EPIYA) patterns and CagA multimerization (CM) motifs of cagA genotypes were examined by performing polymerase chain reactions and DNA sequencing. RESULTS: Of 69 tested H. pylori strains, cagA-positive patients had significantly more severe histological scores in their antrum than cagA-negative patients. Sequence analysis revealed that 94.1% of strains had Western-type cagA containing an EPIYA motif (92.6%) or EPIYT motif (6.4%). The intestinal metaplasia scores in the antral of patients infected with the ABC and ABCC types of cagA were significantly higher than those of patients with AB-type cagA. Interestingly, in patients infected with H. pylori, 46.3% of strains with three EPIYA motifs contained two identical Western-typical CM motifs, and these patients showed significantly higher antrum inflammation scores than patients infected with two identical nontypical-CM motif strains (p=0.02). CONCLUSIONS: In Myanmarese strains, Western-type cagA was predominant. The presence of CM motifs and the proportion of multiple EPIYA-C segments might partially explain the intermediate gastric cancer risk found in Myanmar.

Clinical and histological presentation of helicobacter pylori and gluten related gastroenteropathy

Celiac disease has been reported to be associated with gastric abnormalities. The aim of this study was to assess the relationship between the prevalence of celiac disease and Helicobacter pylori infection in an Iranian population of 250 patients. Biopsies were taken from the gastric antrum and duodenum. Morphology and histology were evaluated using the updated Sydney system and modified Marsh criteria, respectively. To simplify the interpretation of gastric lesions we classified gastritis in macroscopic and microscopic stages. Serology for anti-tissue transglutaminase antibody was performed to determine the presence of celiac disease. Among 250 patients, 232 [93%] had histological evidence of Helicobacter pylori infection. Histological abnormalities [Marsh I to IIIc] were present in 24 [10%]. Of 24 patients, 20 [83%] with histological abnormalities were infected with Helicobacter pylori. Of 250 patients, 25 [10%] had a positive anti-tissue transglutaminase antibody. Of 25 anti-tissue transglutaminase antibody positive patients, 9 [3.6%] had microscopic and macroscopic enteritis [Marsh I to IIIc]. Clinical presentation of celiac disease was not distinguishable from cases infected with Helicobacter pylori. Histology, even in patients with positive serology, was non-specific and unhelpful. We found a high prevalence of Helicobacter pylori infection and chronic gastritis, but neither was associated with celiac disease, in agreement with studies in Western populations