Aslantaş Özkan, Demir Cemil
Department of Microbiology, Faculty of Veterinary Medicine, Mustafa Kemal University, 31030 Hatay, Turkey.
Vocational School of Health Services, Department of the Medical Documentation and Secretarial, Mardin Artuklu University, 47500 Mardin, Turkey.
J Dairy Sci. 2016 Nov;99(11):8607-8613. doi: 10.3168/jds.2016-11310. Epub 2016 Aug 31.
A total of 112 Staphylococcus aureus isolates obtained from subclinical bovine mastitis cases were examined for antibiotic susceptibility and biofilm-forming ability as well as genes responsible for antibiotic resistance, biofilm-forming ability, and adhesin. Antimicrobial susceptibility of the isolates were determined by disk diffusion method. Biofilm forming ability of the isolates were investigated by Congo red agar method, standard tube method, and microplate method. The genes responsible for antibiotic resistance, biofilm-forming ability, and adhesion were examined by PCR. Five isolates (4.5%) were identified as methicillin-resistant Staph. aureus by antibiotic susceptibility testing and confirmed by mecA detection. The resistance rates to penicillin, ampicillin, tetracycline, erythromycin, trimethoprim-sulfamethoxazole, enrofloxacin, and amoxicillin-clavulanic acid were 45.5, 39.3, 33, 26.8, 5.4, 0.9, and 0.9%, respectively. All isolates were susceptible against vancomycin and gentamicin. The blaZ (100%), tetK (67.6%), and ermA (70%) genes were the most common antibiotic-resistance genes. Using Congo red agar, microplate, and standard tube methods, 70.5, 67, and 62.5% of the isolates were found to be biofilm producers, respectively. The percentage rate of icaA, icaD, and bap genes in Staph. aureus isolates were 86.6, 86.6, and 13.4%, respectively. The adhesion molecules fnbA, can, and clfA were detected in 87 (77.7%), 98 (87.5%), and 75 (70%) isolates, respectively. The results indicated that Staph. aureus from sublinical bovine mastitis cases were mainly resistant to β-lactams and, to a lesser extent, to tetracycline and erythromycin. Also, biofilm- and adhesion-related genes, which are increasingly accepted as an important virulence factor in the pathogenesis of Staph. aureus infections, were detected at a high rate.
对从亚临床型牛乳腺炎病例中分离出的112株金黄色葡萄球菌进行了抗生素敏感性、生物膜形成能力以及抗生素耐药性、生物膜形成能力和黏附相关基因的检测。采用纸片扩散法测定分离株的抗菌敏感性。通过刚果红琼脂法、标准试管法和微孔板法研究分离株的生物膜形成能力。采用聚合酶链反应（PCR）检测抗生素耐药性、生物膜形成能力和黏附相关基因。通过抗生素敏感性试验鉴定出5株（4.5%）耐甲氧西林金黄色葡萄球菌，并通过检测mecA基因进行确认。对青霉素、氨苄西林、四环素、红霉素、甲氧苄啶 - 磺胺甲恶唑、恩诺沙星和阿莫西林 - 克拉维酸的耐药率分别为45.5%、39.3%、33%、26.8%、5.4%、0.9%和0.9%。所有分离株对万古霉素和庆大霉素敏感。blaZ（100%）、tetK（67.6%）和ermA（70%）基因是最常见的抗生素耐药基因。使用刚果红琼脂法、微孔板法和标准试管法，分别发现70.5%、67%和62.5%的分离株能够产生生物膜。金黄色葡萄球菌分离株中icaA、icaD和bap基因的百分比分别为86.6%、86.6%和13.4%。分别在87株（77.7%）、98株（87.5%）和75株（70%）分离株中检测到黏附分子fnbA、can和clfA。结果表明，来自亚临床型牛乳腺炎病例的金黄色葡萄球菌主要对β - 内酰胺类抗生素耐药，对四环素和红霉素的耐药程度较低。此外，生物膜和黏附相关基因在金黄色葡萄球菌感染发病机制中作为重要毒力因子越来越受到认可，其检出率很高。
