Norwegian Zoonosis Centre, National Veterinary Institute, Oslo, Norway.
Microb Drug Resist. 2009 Mar;15(1):55-9. doi: 10.1089/mdr.2009.0865.
The occurrence of antimicrobial resistance in Staphylococcus pseudintermedius from skin and ear infections in a representative sample of dogs unexposed to antimicrobial treatment before sampling was examined. The obtained isolates were further examined for genetic polymorphism and genetic background of resistance. A total of 59 isolates of S. pseudintermedius originating from 96 samples of 91 dogs in five different regions in Norway were included in this study. Susceptibility testing was performed using a broth dilution method. Resistant isolates were subjected to polymerase chain reaction for detection of resistance genes. All isolates were subjected to pulsed-field gel electrophoresis to examine the genetic polymorphism. In total, 19% of the isolates were susceptible to all antimicrobial agents included. Resistance to penicillin was most prevalent (70%), followed by resistance to fusidic acid (49%) and oxytetracycline (42%). Resistance to quinolones or cephalosporins was not observed. Resistance to penicillin, tetracycline, and erythromycin was mediated by the blaZ beta-lactamase gene, the tetM gene, and the ermB gene, respectively. One of the fusidic acid-resistant isolates harbored a fusC gene, whereas the mechanisms involved in resistance in the other fusidic acid-resistant isolates remained unknown. Pulsed-field gel electrophoresis showed a high genetic polymorphism of S. pseudintermedius. This study indicates that the occurrence of antimicrobial resistance is common among S. pseudintermedius from dogs unexposed to antimicrobial treatment before sampling, and that there is a high genetic polymorphism among S. pseudintermedius.
本研究旨在检测未经抗菌药物处理的犬只皮肤和耳部感染源金黄色葡萄球菌中间亚种（Staphylococcus pseudintermedius）的抗菌药物耐药性的发生情况。进一步对分离株的遗传多态性和耐药基因背景进行了研究。从挪威五个不同地区的 91 只犬的 96 个样本中获得了 59 株金黄色葡萄球菌中间亚种，这些样本均未经过抗菌药物处理。采用肉汤稀释法进行药敏试验。对耐药分离株进行聚合酶链反应（PCR）检测耐药基因。所有分离株均进行脉冲场凝胶电泳（PFGE）以检测遗传多态性。总的来说，19%的分离株对包括所有抗菌药物在内的所有抗菌药物均敏感。对青霉素的耐药性最为普遍（70%），其次是对夫西地酸（49%）和土霉素（42%）的耐药性。未观察到对喹诺酮类或头孢菌素类的耐药性。青霉素、四环素和红霉素的耐药性分别由 blaZ 内酰胺酶基因、tetM 基因和 ermB 基因介导。1 株夫西地酸耐药分离株携带 fusC 基因，而其他夫西地酸耐药分离株的耐药机制尚不清楚。PFGE 显示金黄色葡萄球菌中间亚种具有高度的遗传多态性。本研究表明，未经抗菌药物处理的犬只皮肤和耳部感染源金黄色葡萄球菌中间亚种的抗菌药物耐药性发生率较高，且金黄色葡萄球菌中间亚种的遗传多态性较高。
