Características genotípicas e fenotípicas de cepas de Escherichia coli isoladas de carne moída bovina in natura

Abstract

Escherichia coli is a bacterium that comprise the normal intestinal flora of warm-blooded animals, responsible for a variety of diseases in humans, as bacteremia, urinary tract and intestinal infections. Some become pathogenic virulence genes after purchasing. It is a frequent contaminant of food, particularly those of animal origin, and when ingested, causes symptoms that characterize the foodborne Diseases such as diarrhea and malaise. The ground beef is a efficientdisseminator of E. coli because it has great nutritional and physicochemical qualities. In addition, a great handling contributes to crosscontamination. The objective of this research was to analyze genotypic and phenotypic characteristics of E. coli strains from ground beef in natura, marketed in a town in the Northwest region of Rio Grande do Sul from November 2012 to March 2013. For the Polymerase Chain Reaction (PCR), we made 26 pools of DNA samples of 262 E. coli strains previously isolated and identified. We investigated the presence of bfpA virulence genes (typical EPEC - tEPEC); eaeA (EPEC/EHEC); stx1 and stx2 (EHEC); hlyA (pO157 EHEC); aggR (EAEC); elt and est (ETEC); and ipaH (EIEC). The sensitivity profile front antimicrobial and the research phenotypes of resistance enzymes, ESBL, KPC, MBL and AmpC were performed by disk-diffusion method. Of the 26 pools analyzed 69.23% contained virulence genes. The bfpA gene was prevalent, present in 46.15% of the analyzed groups. The genes stx1, aggR, stx2, hlyA, eaeA and elt were found in 26.92%; 23.07%; 19.23%; 11.53%; 11.53%; and 3.84% respectively.In contrast they were not identified the genes est and ipaH. The sensitivity profile across antimicrobial showed 100% of sensitivity against aztreonam, ceftazidime, gentamicin, meropenem, and piperacillin/tazobactam and resistance against ampicillin (7.63%), sulfamethoxazole/trimethoprim (5.34%) and cephalothin (3.43%), and 1.14% being resistant to multiple drugs. Resistance enzymes were not detected by phenotypic test. Thus, better hygiene and sanitary precautions are necessary from time of animal slaughter to commercialization of ground beef and other meat products, in order to reduce contamination of feed, mainly by pathogenic microorganisms. Furthermore, greater awareness of the widespread use of antimicrobials in beef cattle breeding should be performed, avoiding the selection of resistant microorganisms to drugs commercially available for treating diseases