Dissertação
Características genotípicas e fenotípicas de cepas de Escherichia coli isoladas de carne moída bovina in natura
Fecha
2016-01-15Autor
Damer, Juliana Raquel da Silva
Institución
Resumen
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