title: Investigation of the antibiotic resistance and biofilm formation of Staphylococcus aureus strains isolated from gangrenous mastitis of ewes.
abstract: In this study, Staphylococcus aureus strains (n = 110) isolated from seven ewe flocks in Sanliurfa, Turkey were screened for antibiotic resistance and biofilmforming ability as well as for genes associated with antibiotic resistance and biofilm-forming ability. All isolates were found to be susceptible to oxacillin, gentamicin, clindamycin, cefoxitin, tetracycline, vancomycin, amoxicillin-clavulanic acid, ciprofloxacin and sulphamethoxazole-trimethoprim. The percent proportions of strains resistant to penicillin G, ampicillin and erythromycin were 27.2% (n = 30), 25.4% (n = 28) and 6.3% (n = 7), respectively. Regarding the antibiotic resistance genes, 32 (29%) isolates carried the blaZ and 8 (7.2%) the ermC gene. Other resistance genes were not detected in the isolates. All isolates showed biofilm-forming ability on Congo red agar (CRA), while 108 (98.18%) and 101 (91.81%) of them were identified as biofilm producers by the use of standard tube (ST) and microplate (MP) methods, respectively. All isolates carried the icaA and icaD genes but none of them harboured the bap gene. The results demonstrated that S. aureus isolates from gangrenous mastitis were mainly resistant to penicillins (which are susceptible to the staphylococcal beta-lactamase enzyme), and less frequently to erythromycin. Furthermore, all of the S. aureus isolates produced biofilm which was considered a potential virulence factor in the pathogenesis of staphylococcal mastitis.
authors.affiliation: Harran University Department of Microbiology, Faculty of Veterinary Medicine Eyyubiye Campus Eyyubiye, Sanliurfa Turkey.
authors.forename: Osman Yaşar
authors.initials: OY
authors.lastname: Tel
authors.forename: Ozkan
authors.initials: O
authors.lastname: Aslantaş
authors.forename: Oktay
authors.initials: O
authors.lastname: Keskin
authors.forename: Ebru Sebnem
authors.initials: ES
authors.lastname: Yilmaz
authors.forename: Cemil
authors.initials: C
authors.lastname: Demir
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D018441:Biofilms; D004352:Drug Resistance, Microbial; D005260:Female; D008414:Mastitis, Bovine; D012756:Sheep; D013203:Staphylococcal Infections / Q000662:veterinary; D013211:Staphylococcus aureus
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins