Antibiotic resistance and integrons in Shiga toxin-producing Escherichia coli (STEC)

COLELLO ROCIO; ETCHEVERRÍA ANALÍA; DI CONZA JOSÉ; GUTKIND GABRIEL; PADOLA NORA LÍA

BRAZILIAN JOURNAL OF MICROBIOLOGY

SOC BRASILEIRA MICROBIOLOGIA

Año: 2015 vol. 46 p. 1 - 5

1517-8382

STEC cause hemorrhagic colitis (HC) and hemolytic-uremic syndrome in humans (HUS). Cattle are the main reservoir of STEC and transmission to humans occurs through food or water contaminated. Pigs are also involved in the transmission of STEC. Antibiotics are used in pig production systems to combat disease and improve productivity and play a key role in dissemination of antibiotic resistance genes among bacteria. Integrons has been identified in resistant bacteria allowing the acquisition and dissemination of antibiotic resistance genes. They contain a site-specific recombination system that recognize and capture the mobile genes cassette. STEC strains isolated from humans and animals have developed antibiotic resistance. In our laboratory, 21 non-157 STEC strains isolated from pigs were analyzed to detect class 1 and 2 integrons by PCR. Eight carried integrons, 7 of them harbored intl2. In other study 545 STEC strains were also analyzed for the presence of intl1 and intl2. Strains carrying intl1 belonged to isolates from environment (n=1), chicken hamburger (n=2), dairy calves (n=4) and pigs (n=8). Two strains isolated from pigs harbored intl2 and only one intl1/intl2, highlighting the presence of intl2 in pigs. Although antibiotic therapy is not recommended for treatment of STEC infections in humans, the selection for multiresistant strains will contribute to the emergence of antibiotic resistant pathogens and facilitate the spread of the mobile resistance elements to other bacteria.