Detection of integrons class 1 and class 2 in VTEC strains isolated from pigs

COLELLO, ROCÍO; MOREDO, FABIANA; ETCHEVERRÍA, ANALÍA I.; LEOTTA, GERARDO; PARMA, ALBERTO E.; PADOLA, NORA L.

Amsterdam

Simposio; 8th International Symposium on Shiga Toxin (Verocytotoxin) - Producing Escherichia coli infections; 2012

INTRODUCTION AND OBJETIVES: In the last 10 years, approximately 500 HUS new annual cases were reported in Argentina, with an incidence of 17/100,000 children under five years old. The production of VT1, VT2 and/or their variants is the primary virulence trait responsible for human disease. VT2e is typically associated wIth pig edema disease and has been detected only rarely in VTEC of human origin. Some studies have show n that VTEC serotypes have developed resistance to antibiotics used in human and veterinary medicine. Humans may obtain antibiotic-resistant E. coli by contact with animals, foods, or environment. The widespread use of antibiotics creates a reservoir of resistant bacteria carrying antibiotic resistance genes. Integrons contain the genetic determinants of the components of a site-specific recombination system which recognize and capture the mobile antibiotic-resistance genes cassette. Integrons include a gene for an integrase (int), an adjacent recombination site (attl), and a strong promoter/s that ensure expression of the integrated cassettes. The aim of this study w as to detect integrons in VTEC strains with antibiotic multiresistance. MATERIAL AND METHODS: Twenty-one VTEC strains isolated from pig faeces from ten farms (named A to J) from Argentina were analysed to detect integrons (int1 and int2) by PCR. RESULTS: Out of twenty-one analysed strains, 8 (38 %) carried integrons encoding genes. These strains belonged to 4 different farms. CONCLUSIONS: The use of antibiotics in animal production systems has determined that bacteria could develop resistance mechanisms originating strains with risk for human if entering a food chain. Integrons are not only associated with resistance to antibiotics, but also with the horizontal transference of resistance genes. Some studies have informed of the presence of integrons in Enterobacteriaceae and Escherichia coli in samples isolated from pigs, not being registered data in VTEC strains so far. In this study integrons class 1 and class 2 w ere detected in VTEC strains isolated from pigs showing that inadequate use of antibiotic as therapeutic agents or growing promoter in veterinary, implies a risk for public health because the acquisition and the horizontal transference of integrons among strains.