Weese J Scott, Faires Meredith, Brisson Brigette A, Slavic Durda
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.
J Am Vet Med Assoc. 2009 Nov 1;235(9):1064-6. doi: 10.2460/javma.235.9.1064.
A 2-year-old dog was evaluated because of complications that developed following tibial plateau leveling osteotomy. Infection of the surgical site developed following removal of the failed implant.
The dog was lame with evidence of a deep surgical site infection, and Staphylococcus pseudintermedius was isolated from the surgical site. Results of in vitro testing indicated that the isolate was resistant to multiple antimicrobials but susceptible to cefoxitin. Subsequent testing confirmed that the isolate was methicillin-resistant S pseudintermedius and was in fact resistant to cefoxitin.
On the basis of results of follow-up testing, doxycycline was administered before and after surgery to remove the surgical implant. The dog recovered without further complications.
Findings suggested that certain strains of methicillin-resistant S pseudintermedius, which appears to be an emerging pathogen in dogs, may be falsely identified as methicillin susceptible on the basis of results of testing for cefoxitin susceptibility because cefoxitin may not induce the mecA gene as reliably in S pseudintermedius as it does in Staphylococcus aureus. Isolates of S pseudintermedius should be considered to likely be methicillin resistant when multidrug resistance is identified, even if susceptibility to some beta-lactam antimicrobials is reported.
一只2岁的犬只因胫骨平台水平截骨术后出现的并发症而接受评估。取出失败的植入物后手术部位发生感染。
该犬跛行，有深部手术部位感染的迹象，从手术部位分离出中间型葡萄球菌。体外测试结果表明，分离株对多种抗菌药物耐药，但对头孢西丁敏感。随后的测试证实该分离株为耐甲氧西林中间型葡萄球菌，实际上对头孢西丁耐药。
根据后续测试结果，在手术前后给予强力霉素以取出手术植入物。该犬康复，无进一步并发症。
研究结果表明，某些耐甲氧西林中间型葡萄球菌菌株似乎是犬类中的一种新兴病原体，基于头孢西丁敏感性测试结果可能会被错误地鉴定为对甲氧西林敏感，因为头孢西丁在中间型葡萄球菌中诱导mecA基因的可靠性可能不如在金黄色葡萄球菌中。当鉴定出多重耐药时，即使报告对某些β-内酰胺类抗菌药物敏感，中间型葡萄球菌分离株也应被视为可能耐甲氧西林。
