Typification of strains of Helicobacter pylori by the detection of the cagA gene and subtypes of the vacA gene
Gómez, J.; Elizalde, J.I.; Marco, F.; Bordas, J.M.; Piqué, J.M.; Jiménez de Anta, M.T.
Enfermedades Infecciosas y Microbiologia Clinica 17(4): 171-175
1999
ISSN/ISBN: 0213-005X PMID: 10365510 Document Number: 500162
Helicobacter pylori infection is probably the most common chronic bacterial infection in the world. The consequences of infection are pathologies like peptic ulcer, chronic gastritis, gastric cancer and gastric MALT lymphoma. The aim of this study was to detect the vacuolating cytotoxin gene (vacA) type, the cytotoxin-associated gen (cagA) of H. pylori isolates and study their association with the vacuolising activity. Gastric biopsy specimens were obtained from dyspeptic patients. Isolates were further genotypically typed by PCR. All strains studied were vacA+ and 55% were cagA+. All cytotoxic strains were cagA+, subtype vacA s1/m1 and corresponded to patients with peptic ulceration. The cagA- strains (11) corresponded to subtype s2/m2. We didn't demonstrate vacuolising activity on subtypes s1/m2 and s2/m2. A high genetic diversity exists among strains in our environment. The subset of bacteria, vacA s1/m1/cagA+, is associated with vacuolising activity in culture cells (tox+).