Antimicrobial susceptibility profile of Enterococcus sp. isolatedfrom Dilúvio stream waters, Porto Alegre, RS, Brazil

Abstract

The aim of this study was to determine the frequency enterococci species from Dilúvio stream, in Porto Alegre RS, and the antimicrobial susceptibility profiles of the isolates to antibiotics of human and veterinary importance. From March to December 2009, water samples were collected from the stream into five distinct points. Three hundred and forty eight enterococci were isolated from water samples collected at five points along the course of the creek flood and identified to the species level through their phenotypic profiles and PCR. The most frequent specie was E. faecium (68.67%), followed by E. faecalis (16.09%), E. casseliflavus (12.07%), E. hirae (2.58%) and E.gallinarum (0.57%). Points 1 and 3 showed no significant differences between the species. The antimicrobial susceptibility tests revealed that isolateswereresistant to erythromycin (81.07%), nitrofurantoin(37.26%), norfloxacin (34.82%), ciprofloxacin (32.55%), chloramphenicol (4.73), tetracycline (2.23%) and vancomycin (0.28%). There was a significant differences in the prevalence of antibiotic- resistant enterococci in the Points 4 and 5 (P <0.05). All isolates were susceptible to ampicillin and gentamicin. Species multiresistant to antibiotics were observed. The results of this study demonstrate that the flood waters of the stream can be a source of spread and persistence of resistant enterococci and their antibiotic resistance genes to humans and the environment, representing risks to the population.