Antimicrobial resistance in Euterococcus faecalis from fishes

Abstract

Enterococci, which are found as commensal in animals and human, can cause infections in definite conditions. The improvement and increment of aquaculture cause to happen a big problem for not only the other bacterial infections but also enterococcal infections in fishes. Enterococci are interesting microorganisms owing the wide range of distribution in nature, high level of antimicrobial resistance, and high mortality rates in enterococcal infections. The aim of this study was to determine the resistance to vancomycin and other antimicrobials in fish isolates of enterococci. Twenty six Enterococcus faecalis strains which were isolated in sick and dead fishes were used in study. Ciprofloxacin, erythromycin, tetracycline, streptomycin, ampicillin, gentamicin, penicillin, and vancomycin susceptibility of E.faecalis strains were examined with agar disc diffusion techniques. The vancomycin resistance phenotype of vancomycin resistant enterococci (VRE) was determined by agar dilution method. Ciprofloxacin, erythromycin, tetracycline, streptomycin, ampicillin, gentamicin, penicillin and vancomycin resistance of E.faecalis strains were found as 34.6%, 3.8%, 3.8%, 96.1%, 11.5%, 92.3%, 11.5%, and 3.8%, respectively. One of the 26 E.faecalis strains (3.8%) was found as vancomycin resistant (VRE) and the vancomycin resistance phenotype of this strain was determined as VanA. These findings showed that ciprofloxacin, streptomycin and gentamicin resistant E faecalis strains were prevalent in fishes. Despite of the low proportion, the presence of a vancomycin resistant E.faecalis strain suggested that fishes must be considered as VRE source.