Los genotipos de Helicobacter pylori en gastritis no atrófica difieren de los encontrados en úlcera péptica, lesiones premalignas y cáncer gástrico en Colombia

Background: Helicobacter pylori is recognized as an etiologic agent of several gastric diseases. Bacterial genotypes have been related to clinical outcome in several populations. Aim: To compare cagA, vacA and iceA genotypes of Colombian isolates from patients with several gastrointestinal diseases, including gastric cancer. Material and methods: We used polymerase chain reactions to amplify vacA, cagA and iceA genes of 137 H pylori isolates coming from 26 patients with gastric cancer (GC), 34 with peptic ulcer (PU), 19 with intestinal metaplasia (IM), 23 with atrophic gastritis (AG) and 35 with non atrophic gastritis (NAG). Results: vacA s1-m1, cagA+, iceA+ were the most frequently found genotypes. vacA s1 and m1 subtypes were found in 92 (67%) and 82 (60%) cases respectively. Sixty three percent were cagA+ and 85% were iceA+. There was a lower prevalence of s1 allele in cases of NAG (43%), compared with GC, PU and IM (81%, 77% and 81% prevalence, respectively, p <0.01). Isolates from NAG also showed a low frequency of vacA m1 subtype (40%) compared with GC or IM (81% and 84% respectively, p <0.01). The prevalence of cagA+ strains was significantly higher in GC patients (80%) than in NAG patients (51.4%, p <0.01). No differences in the frequency of vacA s1a, s1b and iceA subtypes, were observed. Conclusions: A lower frequency of cytotoxic H pylori genotypes such as cagA and vacA s1m1 and a higher frequency of non cytotoxic genotypes, was observed in patients with NAG, when compared to patients with GC or PU. These results suggest that even in Colombia, vacA and cagA could be used as markers of increased virulence (Rev Med Chile 2002; 130: 143-51)