Frequency of vacA, cagA and babA2 virulence markers in Helicobacter pylori strains isolated from Mexican patients with chronic gastritis

Universidad Nacional Autónoma de Mexico, Los Reyes Iztacala, Tlalnepantla, Estado de Mexico, Mexico.
Annals of Clinical Microbiology and Antimicrobials (Impact Factor: 2.19). 04/2009; 8(1):14. DOI: 10.1186/1476-0711-8-14
Source: PubMed


Helicobacter pylori has been strongly associated with chronic gastritis, peptic and duodenal ulcers, and it is a risk factor for gastric cancer. Three major virulence factors of H. pylori have been described: the vacuolating toxin (VacA), the cytotoxin-associated gene product (CagA) and the adhesion protein BabA2. Since considerable geographic diversity in the prevalence of H. pylori virulence factors has been reported, the aim of this work was to establish the H. pylori and vacA, cagA and babA2 gene status in 238 adult patients, from a marginal urban area of Mexico, with chronic gastritis.
H. pylori was identified in cultures of gastric biopsies by nested PCR. vacA and cagA genes were detected by multiplex PCR, whereas babA2 gene was identified by conventional PCR.
H. pylori-positive biopsies were 143 (60.1%). All H. pylori strains were vacA+; 39.2% were cagA+; 13.3% were cagA+ babA2+ and 8.4% were babA2+. Mexican strains examined possessed the vacA s1, m1 (43.4%), s1, m2 (24.5%), s2, m1 (20.3%) and s2, m2 (11.9%) genotypes.
These results show that the Mexican patients suffering chronic gastritis we have studied had a high incidence of infection by H. pylori. Forty four percent (63/143) of the H. pylori strains analyzed in this work may be considered as highly virulent since they possessed two or three of the virulence markers analyzed: vacA s1 cagA babA2 (9.8%, 14/143), vacA s1 babA2 (4.9%, 7/143), and vacA s1 cagA (29.4%, 42/143). However, a statistically significant correlation was not observed between vacAs1, cagA and babA2 virulence markers (chi2 test; P > 0.05).

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    • "Matsunari et al. (2012) identified this genotype in 0.6% of Japanese strains (2/337). In Mexico, studies by Paniagua et al. (2009) and Morales-Espinosa et al. (1999) reported this genotype in adult patients, whereas the results of this study indicate that this allelic combination is present from an early age. "
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    ABSTRACT: Genotypic differences in Helicobacter pylori play an important role in infection. We characterized the diversity of the cagA, cagE, babA2, and vacA genes in H. pylori strains isolated from pediatric patients and the relationship between these genes and clinical disease. Additionally, we employed the Neighbor-net algorithm to predict the behavior of the genotypes of the strains isolated from patients. Of 93 patients analyzed, 32 were positive for infection. A total of 160 H. pylori strains (five isolates per positive patient) were analyzed. A total of 91% and 83% of strains possessed the cagA and cagE genes, respectively. For the vacA gene, 84% of strains possessed the s1 allele, 15% the s2 allele, 81% the m1 allele and 13.8% the m2 allele. The babA2 gene was present in 79% of strains. Infection with H. pylori strains with the vacA (s1m1) genotype was associated with risk of esophagitis and gastritis (p = 0.0001). The combination of cagA and vacA (s1m1) was significantly associated with abdominal pain (p = 0.002); however, EPIYA type was not significantly associated with abdominal pain. A total of 16 different genotypes were identified; the most common genotype was vacAs1m1cagA+cagE+babA2+ (47.5%). A total of 84% of pediatric patients were infected by at least two and up to five different genotypes. The network recovered two genotype groups (A: strains with vacAs1 and B: strains with vacAs2). The presence of multiple paths in the network suggests that reticulate events, such as recombination or reinfection, have contributed to the observed genotypic diversity.
    Full-text · Article · Nov 2014 · Infection Genetics and Evolution
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    • "H. pylori is strongly associated with gastritis and peptic ulcer.[12] The variable prevalence of infection caused by this bacterium in various countries is due to its variable clinical isolates.[16] "
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    ABSTRACT: It is believed that the Helicobacter pylori (H. pylori) vacA gene, as a major virulence determinant (One of the major virulence determinant, not major), may be a risk factor for the development of gastroduodenal diseases. The frequency of vacA genotypes varies in different human populations. This study evaluated the prevalence of vacA alleles/genotypes among dyspeptic patients in Isfahan. One-hundred H. pylori-positive adult patients were examined in this study. After culture of gastric biopsies and DNA extraction from individual H. pylori isolates, the (all H. pylori strains harbor vacA alleles, please replace "presence" with "genotypes") of the vacA s and m alleles were determined using polymerase chain reaction (PCR). There were four vacA mosaicisms, including 28 for s1a/m1 (28%), 23 for s1b/m1 (23%), 26 for s1a/m2 (26%) and 23 for s1b/m2 (23%). The s2 allele was not found. The predominant vacA genotype in patients with non-ulcer dyspepsia and duodenal ulcer was s1a/m2, whereas in patients with adenocarcinoma was s1a/m1. The results showed there was no significant correlation between different genotypes of the vacA and the clinical outcomes and appears to vacA genotypes were not useful determinants for gastrointestinal diseases in our area.
    Full-text · Article · Jan 2014
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    • "However, considering that these virulent strains have also been associated with more severe histological changes such as atrophy or intestinal metaplasia (increased risk of gastric cancer), (Nogueira et al., 2001; Soltermann et al., 2007; Umit et al., 2009) it is of great importance to investigate in a future, whether these H. pylori isolates increase the risk of gastric cancer. Moreover, we determined the presence of babA2 and found that 57% of the isolates were babA2+, which coincides with other South American studies that report gene frequencies ranging from 46% to 82.3% (Lobo Gattia et al., 2005; Quiroga et al., 2005; Paniagua et al., 2009; Torres et al., 2009). In the case of the populations studied, babA2 genes are more often found in populations where the prevalence of duodenal ulcer and gastric cancer has been high (Gonçalves Oliveira et al., 2003). "
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    ABSTRACT: The clinical outcome of Helicobacter pylori infection has been particularly associated with virulence genotypes. These genotypes are useful as molecular markers in the identification of patients that are infected and at high risk for developing more severe gastric pathologies. Our main objective was to determine the prevalence of virulence genotypes cagA, vacA, iceA and babA2 of H. pylori, in patients with functional dyspepsia who are infected with the bacteria. H. pylori genotypes babA2 and cagA as well as vacA and iceA allelic variants were identified by PCR in 122 isolates resulting from 79 patients with functional dyspepsia. A high prevalence of genes cagA+ (71%), vacAs1am1 (34%), babA2 (57%) and iceA1 (87%) was found. The most frequent combined genotype found were cagA+/vacAs1am1/babA2+/iceA1 and cagA-/vacAs1am1/babA2+/iceA1, regardless of any family history of gastric cancer or MALT lymphoma. The very virulent genotype cagA+/vacAs1am1/babA2+/iceA1 prevailed in the studied patients with functional dyspepsia. Our results provide information about the prevalence of four of the more important virulent factors and constitute new evidence on the prevalence of the most virulent H. pylori genotype in patients with functional dyspepsia.
    Full-text · Article · Jun 2012 · Polish journal of microbiology / Polskie Towarzystwo Mikrobiologów = The Polish Society of Microbiologists
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