Resumo

GARCIA C, Apolinaria et al. Genotypying of clinical isolates of Helicobacter pylori by cagA, vacA and babA2 virulence associated genes: First detection of a babA2 positive strain in Chilean patients. Rev. méd. Chile [online]. 2006, vol.134, n.8, pp. 981-988. ISSN 0034-9887.  http://dx.doi.org/10.4067/S0034-98872006000800006.

Background: Helicobacter pylori-associated gastroduodenal diseases depends on host characteristics, environmental conditions and bacterial virulence factors, such as cagA, vacA y babA2 gene products. Moreover, peptic ulcer disease has been related with cagA+, vacAs1m1 strains, while metaplasia and gastric cancer has been associated to cagA+, vacAs1 and babA2+ H pylori strains. Gene babA2 has not yet been described in clinical isolates from Chilean patients. Aim: To investigate the presence of cagA, vacA (s and m) and babA2 genes in clinical isolates of H pylori from Chilean patients. Material and Methods: Sixty six isolates from 41 patients were genotyped by PCR, using primers for s1a, s1b, s2, m1, m2, cagA and babA2 genes as previously described. Results: cagA gene was detected in 16 isolates (24.2%) while vacAs1a, vacAs1b, vacAs2, vacAm1 and vacAm2 were detected in 28 (42.4%), 14 (21.2%), 17 (25.8%), 21 (31.8%) and 29 isolates (43.9%), respectively. One isolate (1.5%) was babA2 positive, being the first isolate with this genotype described in Chile. Besides the babA2+ genotype this clinical isolate also presented cagA+ and vacAs1a which has been related with metaplasia or gastric cancer. Five isolates showed an ulcerogenic profile cagA+, vacAs1m1. Conclusions: The results presented indicate the prevalence of vacAs1m1 genotype among the clinical isolates analyzed, and a low frequency of babA2 genotype (Rev Méd Chile 2006; 134: 981-8).

Palavras-chave : babA protein, Helicobacter pylori; cagA protein, Helicobacter pylori; Helicobacter pylori; vacA protein, Helicobacter pylori.