Revista médica de Chile
versión impresa ISSN 0034-9887
MARTINEZ T, Alejandra et al. Helicobacter pylori: cagA status and vacA genotyping in Chile. Detection of a s2/m1 strain. Rev. méd. Chile [online]. 2001, vol.129, n.10, pp. 1147-1153. ISSN 0034-9887. http://dx.doi.org/10.4067/S0034-98872001001000006.
Background: The genes cagA and vacA encode H pylori virulence factors. Aim: To genotype these genes in H pylori strains isolated from patients with upper gastrointestinal symptoms. Material and methods: We studied 50 patients who underwent an upper gastrointestinal endoscopy, with positive culture for H pylori. Detection of cagA and vacA gerotyping was done using polymerase chain reactions. Results: The gene cagA was detected in 19 samples (38%). Signal sequences s1 and s2 of vacA gene were detected in 16 samples each (32%). There was simultaneous amplification of s1 and s2 in 6 samples and they were not detected in 9 samples. The middle region of vacA was m1 in 9 samples, m2 in 29 samples and there was simultaneous amplification of m1 and m2 in 12 samples. In 16 samples (32%), more than one type of signal sequence or medial region was detected. Of those patients in whom vacA was the only genotype detected, 15 were s2/m2, 7 were s1/m1, 4 were s1/m2 and 1 was s2/m1. Conclusions: In these patients, the infection with cagA- H pylori strains, predominates, the prevalence of infection with s1 or s2 strains is similar and the predominant medial region is m2 (Rev Méd Chile 2001; 129: 1147-53
Palabras clave : Helicobacter pylori; Genotype; Genoma, bacterial.