Helicobacter pylori, ha sido asociado a patologías gástricas y es considerado un factor de riesgo para el desarrollo de cáncer gástrico. El objetivo de este estudio fue caracterizar los genotipos de vacA y la presencia del gen cagA en biopsias provenientes de pacientes con sintomatología gástrica atendidos en el Hospital Universitario Antonio Patricio de Alcalá de Cumaná, Venezuela. Se evaluaron 69 pacientes con indicación endoscópica, empleando la reacción en cadena de la polimerasa. Sólo 42 de ellos (60,86%) mostraron ser positivos para la amplificación de vacA y/o cagA y de éstos el 54,76% amplificó para ambos genes. El genotipo predominante fue m1s1 (61,90%) seguido de infecciones mixtas (33,33%), siendo más frecuentes las asociaciones entre cepas m1s2 con los genotipos m2s2 y m1s1. El 72,5% de las biopsias fueron negativas para el gen cagA. Sin embargo, este se encontró asociado principalmente al genotipo m1s1 (17,39%). Estadísticamente, se encontraron correlaciones muy significativas entre las formas alélicas m1 y s1 (ρ = 0,732), s2 y m2 (ρ = 0,643), significativas m1 y s2 (ρ = 0,279). El Gen cagA mostró correlaciones muy significativas con m1 (ρ = 0,509), m2 (ρ = 0,447) y significativas con s1 (ρ = 0,319) y s2 (ρ = 0,263). Estos resultados muestran la existencia de coinfecciones por distintos genotipos de H. pylori en la población estudiada, que explicaría en parte la baja incidencia de patologías gástricas severas a pesar de estar presente en la región genotipos virulentos de esta bacteria. El elevado porcentaje de coinfecciones observado podría ser el resultado de la influencia de factores geográficos y de etnicidad de la región donde se realizó el estudio.

Helicobacter pylori has been associated with gastric diseases such as gastritis, ulcers, lymphoma gastroduodenal and is considered a risk factor for the development of gastric cancer. The aim of this study was to characterize vacA genotypes and to determine the presence of cagA gene in biopsies from patients with gastric symptoms treated at the University Hospital Antonio Patricio de Alcalá of Cumaná, Venezuela. Sixty nine patients with endoscopic indication were evaluated using the polymerase chain reaction (PCR). Only 42 (60.86%) of those patients were positive for amplification of vacA and/or cagA and of these, 54.76% amplified for both genes. The predominant genotype was m1s1 (61.90%) followed by mixed infections (33.33%), being the most frequent associations among strains with genotypes m1s2, m2s2 and m1s1. From the biopsies performed 72.5% were negative for the cagA gene. However, this was found to be associated mainly to genotype m1s1 (17.39%). Statistically highly significant correlations were found among the allelic forms m1 and s1 (ρ = 0.732), s2 and m2 (ρ = 0.643), significant m1 and s2 (ρ = 0.279). Gene cagA showed highly significant correlations with m1 (ρ = 0.509), m2 (ρ = 0.447) and significant with s1 (ρ = 0.319) and s2 (ρ = 0.263). These results show the existence of co-infections with different genotypes of H. pylori in the studied population. They, would explain in part the low incidence of severe gastric pathologies despite being present in the region virulent genotypes of this bacterium. The high percentage of coinfections observed could be the result of the influence of geographic and ethnicity factors in the region where the study was conducted.

Las infecciones por microorganismos gastrointestinales constituyen hoy en día una de las principales causas de morbilidad y mortalidad en países en vías de desarrollo. Nos planteamos como objetivo evaluar la posible asociación entre la presencia de parásitos intestinales y la infección por Helicobacter pylori, y el comportamiento de anticuerpos séricos y secretores en una población infantil de la etnia Warao del Edo. Delta Amacuro, Venezuela. La presencia de parásitos se determinó por examen microscópico directo de las heces. Los niveles séricos de IgE total, IgG anti H. pylori e IgA anti Giardia duodenalis; y los secretores IgA total y específica a G. duodenalis y H. pylori en muestra de saliva, se determinaron utilizando el método de ELISA. El 65% de los niños estaban parasitados por protozoarios, observándose un 47% de poliparasitismo. Encontramos una mayor seroprevalencia de H. pylori en el grupo de niños no parasitados (46%) comparado con los parasitados (25%) (P<0,05). Sin embargo, los niños seropositivos a H. pylori y parasitados con G. duodenalis mostraron niveles séricos de IgE total mayores que los no parasitados (P<0,01); en contraparte, los niveles de IgA secretora total y especifica a H. pylori y G. duodenalis estaban disminuidos (P<0,05). Es posible que la respuesta inflamatoria generada por Giardia pueda aumentar los niveles de IgE total y disminuir la respuesta de IgA secretora favoreciendo la instauración de la infección por H. pylori.

The infections for gastrointestinal microorganisms represent nowadays one of the major reasons of morbidity and mortality in developing countries. We had evaluated both, the possible association between the presence of intestinal parasites and infection by Helicobacter pylori, and the production of serum and salivary antibodies in Amerindian Warao children from the Orinoco Delta, Venezuela. The prevalence of parasites was determined by faecal examination. The levels of serum antibodies (total IgE, specific anti- H. pylori IgG and anti G. duodenalis IgA) and salivary antibodies (total and specific IgA to G. duodenalis and H. pylori), was determined by ELISA. 65% of the child population was parasitized by protozoos, and a 47% of polyparasitism was observed. We found a major seroprevalence of H. pylori in the group of children not parasitized (46 %) compared with the parasitized ones (25 %) (P<0.05). Nevertheless, the seropositive children to H. pylori and parasitized with G. duodenalis showed levels of total IgE higher than the non parasitized ones (P<0.01); in contrast, levels of total and specific secretory IgA to H. pylori and G. duodenalis were decreased (P<0.05). It is possible that the inflammatory response generated by G. duodenalis infection may increase levels of total IgE and diminish secretory IgA response favoring the establishment of infection by H. pylori.

The aim of this study was to determine the presence of Helicobacter pylori cytotoxin-associated gene (cagA)/vacuolating cytotoxin gene (vacA) among patients with chronic gastritis in Cuba and Venezuela. Gastric antrum biopsies were taken for culture, DNA extraction and PCR analysis. Amplification of vacA and cagA segments was performed using two regions of cagA: 349 bp were amplified with the F1/B1 primers and the remaining 335 bp were amplified with the B7629/B7628 primers. The VA1-F/VA1-R set of primers was used to amplify the 259-bp (s1) or 286-bp (s2) product and the VAG-R/VAG-F set of primers was used to amplify the 567-bp (m1) or 642-bp (m2) regions of vacA. cagA was detected in 87% of the antral samples from Cuban patients and 80.3% of those from Venezuelan patients. All possible combinations of vacA regions were found, with the exception of s2/m1. The predominant combination found in both countries was s1/m1. The percentage of cagA+ strains was increased by the use of a second set of primers and a greater number of strains was amplified with the B7629/B7628 primers in the Cuban patients (p = 0.0001). There was no significant difference between the presence of the allelic variants of vacA and cagA in both populations. The predominant genotype was cagA+/s1m1 in both countries. The results support the necessary investigation of isolates circulating among the human population in each region.