cagA/vacA genotyping of Helicobacter pylori strains isolated from Cuban and Venezuelan patients
Abstract number: P638
Guariglia V., Ortiz D., Cavazza M., Correnti M., Avila M., Gutiererz B., Perrone M., Megraud F.
Among the different genetic determinants involved in H. pylori virulence we find the citotoxin associated gene (cagA) and the vacuolating citotoxin gene (vacA). Different studies have shown the importance of the presence of these genes in the strain affecting a patient and the development of a gastric disease.
Objective: The aim of the study was to determine the presence of different H. pylori cagA/vacA genotypes among patients with gastritis in Cuba and Venezuela.
Methods: Biopsies were taken from 61 patients from Venezuela and from 71 patients from Cuba. Biopsies were cultured on selective media. DNA from the biopsies was obtained using a proteinase K protocol. A region of 349 pb of the cagA gene was amplified by PCR using the primers F1/B1, VA1-F/VA1-R set of primers to amplify the 259 bp (s1) or the 286 bp (s2) regions of the conserved portion of the vacA gene and VAG-R/VAG-F set of primers to amplify the 567bp (m1) or the 642bp (m2) regions of the conserved portion of the vacA gene. All the amplified regions were resolved on a 1% agarose gel electrophoresis at 80 volts for approximately 2 hours.
Results: The 349pb region of the cagA gene was amplified in 34 of the 61 Venezuelan patients (56%) and in 20 of the 71 Cuban patients (28%). We found a significant difference (p = 0.0015) between the presence of the cagA gene in both countries. When we analysed the prevalence of cagA related to the allelic variants we found a significant difference between both countries: in Venezuela we observed a significant higher percentage of the genotype cagA positive/m1s1, in comparison with Cuba (p = 0.0025). The percentage of cagA negative/m1s1 strains in Cuba was significantly higher than in Venezuela (p = 0.04). Out of the 71 patients from Cuba we found that in 8 of them there was co infection with a least two different strains since we detected both m1 and m2 alleles on them.
Conclusion: We found significant differences between the genotypes of the strains from both countries. Since the cagA and vacA genes are some of the virulence factors of H. pylori related to its pathogenesis and the severity of the gastric disease, these results are of great importance to the regional health systems of each country for the control, tracking and prevention of gastric cancer.
Grants: FONACIT G-2005000371 / LOCTI-IBA-022007 and IBA-032007. Inalum-Alumnware
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
|Back to top|