金黄色葡萄球菌从乳腺炎萨希瓦尔牛中分离的抗生素耐药性和致病性因素。
Antibiotic resistance and pathogenicity factors in Staphylococcus aureus isolated from mastitic Sahiwal cattle.
机构信息
Livestock Genome Analysis Laboratory, National Dairy Research Institute, Karnal 132 001, India.
出版信息
J Biosci. 2011 Mar;36(1):175-88. doi: 10.1007/s12038-011-9004-6.
Methicillin-resistant Staphylococcus aureus (MRSA) poses a serious problem in dairy animals suffering from mastitis. In the present study, the distribution of mastitic MRSA and antibiotic resistance was studied in 107 strains of S. aureus isolated from milk samples from 195 infected udders. The characterizations pathogenic factors (adhesin and toxin genes) and antibiotic susceptibility of isolates were carried out using gene amplification and disc diffusion assays, respectively. A high prevalence of MRSA was observed in the tested isolates (13.1%). The isolates were also highly resistant to antibiotics, i.e. 36.4% were resistant to streptomycin, 33.6% to oxytetracycline, 29.9% to gentamicin and 26.2% each to chloramphenicol, pristinomycin and ciprofloxacin. A significant variation in the expression of pathogenic factors (Ig, coa and clf) was observed in these isolates. The overall distribution of adhesin genes ebp, fib, bbp, fnbB, cap5, cap8, map and cna in the isolates was found to be 69.1, 67.2, 6.5, 20.5, 60.7, 26.1, 81.3 and 8.4%, respectively. The presence of fib, fnbB, bbp and map genes was considerably greater in MRSA than in methicillin-susceptible S. aureus (MSSA) isolates. The proportions of toxin genes, namely, hlb, seb, sec, sed, seg and sei, in the isolates were found to be 94.3, 0.9, 8.4, 0.9, 10.2 and 49.5%, respectively. The proportions of agr genes I, II, III and IV were found to be 39.2, 27.1, 21.5 and 12.1%, respectively. A few isolates showed similar antibiotic-resistance patterns, which could be due to identical strains or the dissemination of the same strains among animals. These findings can be utilized in mastitis treatment programmes and antimicrobials strategies in organized herd.
耐甲氧西林金黄色葡萄球菌（MRSA）给患有乳腺炎的奶牛带来了严重的问题。在本研究中，从 195 个受感染的乳房的牛奶样本中分离出的 107 株金黄色葡萄球菌中，研究了乳腺炎 MRSA 的分布和抗生素耐药性。使用基因扩增和圆盘扩散试验分别对分离株的致病因子（粘附素和毒素基因）和抗生素敏感性进行了表征。在测试的分离株中观察到高比例的耐甲氧西林金黄色葡萄球菌（13.1%）。分离株还对抗生素高度耐药，即 36.4%对链霉素耐药，33.6%对土霉素耐药，29.9%对庆大霉素耐药，26.2%对氯霉素、普里西霉素和环丙沙星耐药。在这些分离株中观察到致病因子（Ig、coa 和 clf）的表达存在显著差异。在分离株中发现粘附素基因 ebp、fib、bbp、fnbB、cap5、cap8、map 和 cna 的总体分布分别为 69.1%、67.2%、6.5%、20.5%、60.7%、26.1%、81.3%和 8.4%。在耐甲氧西林金黄色葡萄球菌中，fib、fnbB、bbp 和 map 基因的存在明显高于甲氧西林敏感金黄色葡萄球菌（MSSA）分离株。分离株中毒素基因 hlb、seb、sec、sed、seg 和 sei 的比例分别为 94.3%、0.9%、8.4%、0.9%、10.2%和 49.5%。agr 基因 I、II、III 和 IV 的比例分别为 39.2%、27.1%、21.5%和 12.1%。少数分离株表现出相似的抗生素耐药模式，这可能是由于相同的菌株或同一菌株在动物之间的传播。这些发现可用于乳腺炎治疗方案和有组织牛群中的抗菌策略。
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