Kot B, Piechota M, Antos-Bielska M, Zdunek E, Wolska K M, Binek T, Olszewska J, Guliński P, Trafny E A
Department of Microbiology, Institute of Biology, Siedlce University of Natural Sciences and Humanities, Bolesława Prusa 12, 08-110 Siedlce, Poland.
Pol J Vet Sci. 2012;15(4):741-9. doi: 10.2478/v10181-012-0113-4.
Investigation of antimicrobial resistance and genetic relatedness of staphylococci from milk of cows with mastitis and cowshed environment was the aim of this study. Antimicrobial resistance against 14 antimicrobials were determined by using a disc diffusion method. Genetic similarity between the most frequently isolated species was analysed by PFGE (pulsed-field gel electrophoresis). Haemolytic activity, DNase, protease and esterase production was also investigated. Coagulase-negative Staphylococcus species were isolated from 30.8% of milk samples from cows with mastitis. The most frequently isolated species was Staphylococcus xylosus and yield of these organisms was significantly associated with milk of mastitis cows. S. epidermidis was a predominant penicillin-resistant species. High frequency of resistance to lincomycin was observed among isolates of S. sciuri (54.2%) and S. xylosus (25.9%) from cows with mastitis. PFGE (pulsed-field gel electrophoresis) analysis of 29 Staphylococcus aureus isolates showed the presence of 17 PFGE pulsotypes. Isolates of S. sciuri (n = 36) had unique PFGE patterns. Some S. xylosus isolates from milk and milker's hands had the same PFGE pulsotypes, and this observation could indicate that dairyman may be a potential source of the infection. The pulsotype of each of the remaining isolates of S. xylosus suggested that they might have come from common environmental sources; however, these isolates differed in antibiotic resistance pattern or virulence traits. Therefore, knowledge about antibiotic sensitivity pattern and virulence factors of a CNS isolate, besides its genotype, may be informative in tracking the source of the infection.
本研究旨在调查患乳腺炎奶牛的牛奶及牛舍环境中葡萄球菌的耐药性及基因相关性。采用纸片扩散法测定对14种抗菌药物的耐药性。通过脉冲场凝胶电泳（PFGE）分析最常分离出的菌种之间的基因相似性。还研究了溶血活性、DNase、蛋白酶和酯酶的产生情况。从30.8%的患乳腺炎奶牛的牛奶样本中分离出凝固酶阴性葡萄球菌。最常分离出的菌种是木糖葡萄球菌，这些菌的检出率与患乳腺炎奶牛的牛奶显著相关。表皮葡萄球菌是主要的耐青霉素菌种。在患乳腺炎奶牛分离出的松鼠葡萄球菌（54.2%）和木糖葡萄球菌（25.9%）菌株中观察到对林可霉素的高耐药率。对29株金黄色葡萄球菌进行PFGE（脉冲场凝胶电泳）分析，显示存在17种PFGE脉冲型。松鼠葡萄球菌（n = 36）菌株具有独特的PFGE图谱。从牛奶和挤奶工人手上分离出的一些木糖葡萄球菌菌株具有相同的PFGE脉冲型，这一观察结果表明挤奶工人可能是感染的潜在来源。其余木糖葡萄球菌菌株的脉冲型表明它们可能来自共同的环境来源；然而，这些菌株在抗生素耐药模式或毒力特征方面存在差异。因此，除了基因型外，了解中枢神经系统分离株的抗生素敏感性模式和毒力因子可能有助于追踪感染源。
