ABSTRACT
BACKGROUND: The burden of Helicobacter pylori-induced gastric cancer varies based on predominant H. pylori population in various geographical regions. Vietnam is a high H. pylori burden country with the highest age-standardized incidence rate of gastric cancer (16.3 cases/100,000 for both sexes) in Southeast Asia, despite this data on the H. pylori population is scanty. We examined the global context of the endemic H. pylori population in Vietnam and present a contextual and comparative genomics analysis of 83 H. pylori isolates from patients in Vietnam. RESULTS: There are at least two major H. pylori populations are circulating in symptomatic Vietnamese patients. The majority of the isolates (~ 80%, 66/83) belong to the hspEastAsia and the remaining belong to hpEurope population (~ 20%, 17/83). In total, 66 isolates (66/83) were cagA positive, 64 were hspEastAsia isolates and two were hpEurope isolates. Examination of the second repeat region revealed that most of the cagA genes were ABD type (63/66; 61 were hspEastAsia isolates and two were hpEurope isolates). The remaining three isolates (all from hspEastAsia isolates) were ABC or ABCC types. We also detected that 4.5% (3/66) cagA gene from hspEastAsia isolates contained EPIYA-like sequences, ESIYA at EPIYA-B segments. Analysis of the vacA allelic type revealed 98.8% (82/83) and 41% (34/83) of the strains harboured the s1 and m1 allelic variant, respectively; 34/83 carried both s1m1 alleles. The most frequent genotypes among the cagA positive isolates were vacA s1m1/cagA + and vacA s1m2/cagA + , accounting for 51.5% (34/66) and 48.5% (32/66) of the isolates, respectively. CONCLUSIONS: There are two predominant lineages of H. pylori circulating in Vietnam; most of the isolates belong to the hspEastAsia population. The hpEurope population is further divided into two smaller clusters.
ABSTRACT
Aims. To investigate H. pylori infection rate and evaluate a combined set of tests for H. pylori diagnosis in Vietnamese patients with acute peptic ulcer bleeding (PUD). Methods. Consecutive patients with acute PUB were enrolled prospectively. Rapid urease test (RUT) with 3 biopsies was carried out randomly. Patients without RUT or with negative RUT received urea breath test (UBT) and serological and urinary H. pylori antibody tests. H. pylori was considered positive if RUT or any noninvasive test was positive. Patients were divided into group A (RUT plus noninvasive tests) and group B (only noninvasive tests). Results. The overall H. pylori infection rate was 94.2% (161/171). Groups A and B had no differences in demographic characteristics, bleeding severity, endoscopic findings, and proton pump inhibitor use. H. pylori-positive rate in group A was significantly higher than that in group B (98.2% versus 86.7%, p = 0.004). The positive rate of RUT was similar at each biopsy site but significantly increased if RUT results from 2 or 3 sites were combined (p < 0.05). Conclusions. H. pylori infection rate in Vietnamese patients with acute PUB is high. RUT is an excellent test if at least 2 biopsies are taken.
