Mkize Nelisiwe, Zishiri Oliver T, Mukaratirwa Samson
School of Life Sciences, University of KwaZulu-Natal.
J S Afr Vet Assoc. 2017 May 4;88(0):e1-e7. doi: 10.4102/jsava.v88i0.1416.
Antimicrobial resistance of Staphylococcus aureus in human and veterinary medicine is a serious worldwide problem. The aim of this study was to investigate the prevalence of S. aureus in commercial broiler chickens as well as to establish antimicrobial susceptibility and the distribution of genetic determinants conferring resistance and virulence. One hundred and ninety-four samples were aseptically collected from broiler chicken slaughterhouses and retail outlets around the Durban metropolitan area in South Africa. Microbiological and molecular methods were used to detect the presence of S. aureus as well as its resistance- and virulence-associated genes. Polymerase chain reaction (PCR) was used to confirm the presence of S. aureus by amplifying the nuc gene. Approximately 54% of 194 samples were positive for S. aureus. The disc diffusion technique was used to investigate antimicrobial susceptibility profiles of the S. aureus isolates to a battery of 10 antimicrobial agents, namely ampicillin, chloramphenicol, gentamicin, erythromycin, cefoxitin, kanamycin, streptomycin, tetracycline, vancomycin and trimethoprim. The results demonstrated that S. aureus isolates of abattoir origin had a high level (79.4%) of resistance to tetracycline, followed by ampicillin, vancomycin, cefoxitin, trimethoprim, erythromycin and streptomycin with resistance rates of 65.1%, 61.9%, 60.3%, 58.7%, 57.1% and 46.0%, respectively. Staphylococcus aureus isolates of retail origin exhibited higher antimicrobial resistance prevalence rates than those of abattoir origin. Tetracycline had the highest resistance rate (100%), followed by cefoxitin (91.7%), erythromycin (83.3%), streptomycin (83.3%) and kanamycin (66.7%). All isolates were resistant to two or more antimicrobial agents. Out of the four virulence genes that were screened, only two were detected (coagulase and protein A); however, their prevalence rates were very low. All antimicrobial resistance genes screened were detected (mecA, BlaZ and tetK), although their prevalence did not correspond with antimicrobial susceptibility testing.
金黄色葡萄球菌在人类医学和兽医学中的抗菌耐药性是一个严重的全球性问题。本研究的目的是调查商业肉鸡中金黄色葡萄球菌的流行情况，并确定其抗菌药敏性以及赋予耐药性和毒力的遗传决定因素的分布。从南非德班都会区周围的肉鸡屠宰场和零售店无菌采集了194份样本。采用微生物学和分子方法检测金黄色葡萄球菌的存在及其耐药和毒力相关基因。通过聚合酶链反应（PCR）扩增nuc基因来确认金黄色葡萄球菌的存在。194份样本中约54%的金黄色葡萄球菌呈阳性。采用纸片扩散法研究金黄色葡萄球菌分离株对一组10种抗菌药物的药敏谱，这10种抗菌药物分别是氨苄西林、氯霉素、庆大霉素、红霉素、头孢西丁、卡那霉素、链霉素、四环素、万古霉素和甲氧苄啶。结果表明，屠宰场来源的金黄色葡萄球菌分离株对四环素的耐药水平较高（79.4%），其次是氨苄西林、万古霉素、头孢西丁、甲氧苄啶、红霉素和链霉素，耐药率分别为65.1%、61.9%、60.3%、58.7%、57.1%和46.0%。零售来源的金黄色葡萄球菌分离株的抗菌耐药流行率高于屠宰场来源的分离株。四环素的耐药率最高（100%），其次是头孢西丁（91.7%）、红霉素（83.3%）、链霉素（83.3%）和卡那霉素（66.7%）。所有分离株对两种或更多种抗菌药物耐药。在筛选的4种毒力基因中，仅检测到两种（凝固酶和蛋白A）；然而，它们的流行率非常低。所有筛选的抗菌耐药基因均被检测到（mecA、BlaZ和tetK），尽管它们的流行率与抗菌药敏试验结果不一致。
