Investigation of antimicrobial susceptibility for enterococci isolated from cats and dogs and the determination of resistance genes by polymerase chain reaction


Abstract: The aim of this study was to investigate the antimicrobial susceptibility and to determinate the resistance genes by Polymerase Chain Reaction (PCR) among enterococci isolated from healthy cats and dogs in İzmir, Turkey. From a total of 114 rectal swabs, 91 (31 cats and 60 dogs) stains were isolated as enterococci. Twenty eight isolates were identified as Enterococcus faecalis and 63 as Enterococcus faecium with the API 20 IDStrep system. Antimicrobial susceptibilities were determined by disc diffusion. Susceptibility rates of all enterococci strains were found as 100.0%, 95.6%, 94.5%, 87.9%, 84.6%, 30.8%, 29.7%, and 0.0% for teicoplanin, penicillin, vancomycine, chloramphenicol, gentamycin, erythromycin, tetracycline, and clindamicin, respectively. Of 91 enteroccocci isolates 14 (15.4%) were found susceptible to all antimicrobials tested while 77 (84.6%) strains were resistant. All isolates were found resistant to clindamicin while 5 E. faecium strains had an intermediate resistance to vancomycin. None of the intermediate resistant vancomycin strains has any vanA, vanB, or vanC genes. From 91 isolates 4, 11, 14, 63, and 64 were found resistant to penicillin, chloramphenicol, gentamycin, erythromycin, and tetracycline, respectively. Sixty two tetracycline resistant strains had tet(M) gene. From erythromycin resistant strains 2 and 54 had erm(A) and erm(B). Gentamycin resistance was detected for 14 isolates from which 10 had aac(6')-aph(2') genes. Seven strains have the cat gene of 11 chloramphenicol resistant strains. The results revealed that there was a high level of antimicrobial resistance among enterococci isolated from healthy cats and dogs and they pose a potential risk for transmission of enterococci to humans.

Keywords: Dog, cat, enterococci, antimicrobial susceptibility, resistance genes, PCR

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