Perfil de resistência de cepas de Escherichia coli isoladas de corvina Icropogonias furnieri (Desmarest, 1823) frente a antimicrobianos comerciais e naturais

Abstract

Infection control, especially hospital infections and food poisoning, becomes more difficult to treat when the pathogens responsible for causing such infections are resistant to existing antimicrobials, this fact is associated with the indiscriminate use of antimicrobials that causes selective pressure on microorganisms. In the present study was intent to verify the susceptibility of 17 strains of Escherichia coli isolated from fish to commercial and naturally antimicrobials, and to investigate the possible resistance mechanisms used by them. It was used the antibiogram test to select the resistant isolates to antimicrobial β-lactams, it was also verified the production of β-lactamases enzymes by the microrganisms using phenotypic tests. Was also evaluated the antioxidant and antimicrobial activity of the ethanolic extracts of aroeira (Schinus terebinthifolius) and mastruz (Dysphania ambrosioides) against E. coli strains. The isolates showed considerable rates of β-lactam resistance: Cefotaxime (64.7%) and Ampicillin (52.9%), and intermediate resistance to Ceftriaxone (47%). Among the isolates analyzed 15 reacted positive for the production of β-lactamase enzyme. The ethanolic extracts of aroeira and mastruz show antioxidant activity in the DPPH test, the aroeira extracts were not effective in inhibiting the growth of E. coli isolates. The extracts of the mastruz presented halo formation, but smaller than the minimum size recommended by the NCCLS to be considered as inhibitory activity. The isolates of E. coli showed resistance to commercial and natural antimicrobials used in the tests, presenting resistance mechanisms such as the production of β-lactamases enzymes.