Objective: The intrinsic antibiotic resistance of enterococci and their ability to rapidly gain additional antibiotic resistance make it difficult to treat infections. In animals, enterococcal infections are rarely treated with antimicrobial agents. However, during the treatment of other infections, when growth promoters or prophylactic antibiotics are used, enterococci in the gastrointestinal tract are exposed to the antimicrobials. The aim of this study was to investigate the differences in regional distribution of antibiotic-resistant Enterococci strains isolated from cattle and cattle farmers in Denizli, Turkey.

Method: Samples collected from four regions (21 settlements) in and around Denizli. Rectal swabs and stool specimens from 72 cattle and 111 cattle farmers were sown on Enterococcosel Agar (ECA) and Enterococcosel Broth medium (Becton Dickinson, Heidelberg, Germany) for isolation of bacteria. Colony morphology, haemolysis characteristics in sheep blood agar, Gram staining, catalase test, 40% biliary hydrolysis, 10°C and 45°C reproduction characteristics, 6.5% NaCl growth ability and pyrrolidonyl-beta-naphthylamide tests were performed to identify enterococci. The antibiotic susceptibility of the isolated enterococci was investigated using the Kirby-Bauer disk diffusion method and Mueller-Hinton agar medium. Sensitivities to beta-lactam antibiotics (penicillin, 10 IU; ampicillin, 10 μg; cefaclor, 30 μg; and cephalothin, 30 μg), aminoglycosides (high concentrations of gentamicin, [120 μg]; and streptomycin, [300 μg]), quinolone (ciprofloxacin, 5 μg) and tetracycline (30 μg) were examined.

Results: A total of 161 Enterococcus strains were isolated in this study, 96 from cattle farmers and 65 from cattle. Ciprofloxacin resistance in isolates from cattle farmers was found to be higher in Regions II, III, and IV than in Region I. Beta-lactam and ciprofloxacin resistance in isolates from cattle was found to be higher in Regions I and II than in Regions III and IV. Tetracycline resistance was not found in any of the bovine isolates.

Conclusion: According to the data obtained in the study, it was predicted that the use of antibiotics in veterinary medicine varies widely by region, and that different antibiotic resistances may be seen in isolates from cattle farmers and cattle according to the antibiotics used in each region.