Polymorphism of cagA and vacA genes in Helicobacter pylori isolated from gastroduodenal diseas patients in Central Vietnam

<i>H. pylori</i> plays a significant role in the pathogenesis of upper alimentary tract diseases. Vietnam is a developing country with high prevalence of <i>H. pylori</i> infection and an intermediate risk of gastric cancer. The aim of this thesis was to determine the antibiogram and the molecular basis of the resistance pattern; to investigate <i>cagA</i> and <i>vacA</i> genotypes, and to determine a clinical relevance of <i>cagA</i> and <i>vacA</i> polymorphisms of <i>H. pylori</i> strains isolated from dyspeptic patients in Central Vietnam. <br>We examined dyspeptic patients who were referred to Hue University Hospital between July 2012 and January 2014. A total of 92 strains antibiogram was performed by E-test and 96 extracted DNA samples from 96 strains were available for analysis. Point mutations related to clarithromycin and levofloxacin on 23S <i>rRNA</i> and <i>gyrA</i> genes were detected by sequencing. <i>vacA</i> and <i>cagA</i> genotyping were carried out using PCR and sequencing, then their clinical relevance was further analyzed.</br> We highlight a very high resistance rate in Central Vietnam with 56.5% of multiple resistance and higher prevalence of secondary resistance <i>versus</i> primary resistance. Data on determinants of resistance to clarithomycin and levofloxacin are new information in Vietnam. <i>cagA</i> positive <i>status</i>, East Asian <i>cagA</i> type and <i>vacA</i> s1i1m1 type are the most predominant in gastric ulcer and gastric cancer. The prevalence of <i>cagA</i> negative status and Western <i>cagA</i> type is higher than that reported in previous studies in Vietnam.