Helicobacter pylori vacAs1a and s1b alleles from clinical isolates from different regions of Chile show a distinct geographic distribution

Abstract

Differences in geographic distribution of the s and m vacA alleles in Chile and a relationship of s1b m1 genotype with gastritis were found. Sequence data in part support a hispanic origin for the vacA genotype. Asymmetric distribution of genotypes s1b m1 and s2 m2 recedes H Pylori strain distribution in Spain and Portugal.

Helicobacter pylori genotypes among patients in a university hospital in Egypt: identifying the determinants of disease severity

“…22 The distribution of vacAs1a and vacAs1b varies also between different areas in the same country, as in Pakistan and Chilli. 23,24 Contradictory to studies demonstrating a higher risk for development of peptic ulcer disease upon gastric infection with H. pylori strains containing type vacAs1 allele/subtypes 25 , we found that this correlation is non-significant, as shown in table 3. A similar finding has also been concluded from eastern Asia 26 , Iraq and Iran.…”

Relationship between Helicobacter pylori virulence factors and regulatory cytokines as predictors of clinical outcome

“…Strains that possess an s1/m1 vacA genotype are considered as most virulent with an increased risk of peptic ulcer disease and gastric cancer and enhanced gastric epithelial cell injury compared to those that possess s2/m2 alleles [24]. Prior work from our group showed that the most prevalent VacA genotype in Chilean patients was s1bm1 with 76%, followed by s1a m1 with 21% and s2 m2 that occurred in only 3% [13]. In the current study 91.2% of H. pylori-infected patients were carrying VacA positive strains also with higher proportion of s1bm1 genotype.…”

“…The sequences were done in ABI Prims-3100 genetic analyzer (Apllied Biosyztems). The sequences of the fragments were published in the service of the National Library of Medicine and the National Institute of Health (pubmed central) in a previous work done by our group [13]. Campylobacter yeyuni ATCC 29428 was used as DNA source in negative control samples and the strains ATCC 26695, ATCC 43504, J99, CHCTX-1 [17], 8823 and 8822 were used as positive control of vacA PCR amplification.…”

“…H. pylori is a relevant health problem among developing countries and few data concerning correlation between bacterial virulence factors and clinical outcomes is known in South America, particularly in Chile, which is a unique site for these studies, comparing outcomes and bacterial factors in host living in different regions because differences of vacA genotypes distribution in H. pylori along the country [13].…”

Análisis molecular de Helicobacter pylori (genes de patogenicidad) en biopsias gástricas de pacientes de la Sierra y Oriente Ecuatorianos

“…Helicobacter pylori (H. pylori) es una bacteria Gram negativa que infecta el estómago de los humanos y es considerada la causa etiológica de la úlcera péptica (UP) y el cáncer gástrico (CG) (1). Una vez que la bacteria coloniza al huésped, el microorganismo puede permanecer en el hospedador por años o décadas (2). Varios factores contribuyen en la colonización del H. pylori, por una parte, la colonización de la bacteria está asociada a elementos del hospedador tales como factores socioeconómicos, factores ambientales y estilo de vida (consumo de alcohol y cigarrillo, consumo de sal y exceso de peso) (3).…”