Welch W D, Southern P M
J Clin Microbiol. 1984 Jun;19(6):831-3. doi: 10.1128/jcm.19.6.831-833.1984.
Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen in hospital environments, and optimal detection of MRSA requires nonroutine methods in clinical microbiology laboratories. One such method is an incubation temperature of 30 degrees C in contrast to the more commonly used temperature of 35 degrees C. To determine the percentage of MRSA isolates that would be missed if only one temperature were used, we evaluated methicillin resistance and susceptibility of 2,397 S. aureus isolates by agar dilution at 30 and 35 degrees C. Of the clinical isolates, 93% showed matching MICs of methicillin at both temperatures. Another 6.8% (162) showed different MICs at 30 and 35 degrees C, with 60 of the 162 isolates (2.5% of all isolates studied) being resistant to methicillin at 30 degrees C but susceptible at 35 degrees C (temperature-discrepant MRSA). MICs of other antimicrobial agents, measured at 35 degrees C, revealed an unusual pattern of susceptibility of these temperature-discrepant MRSA isolates. In contrast to previously reported resistance of MRSA at 35 degrees C to erythromycin, clindamycin, gentamicin, and tetracycline, the temperature-discrepant MRSA isolates were susceptible to these agents. This resistance pattern may be of value in identifying questionable MRSA isolates when only one incubation temperature is used.
耐甲氧西林金黄色葡萄球菌（MRSA）是医院环境中的一种重要病原体，在临床微生物实验室中，对MRSA进行最佳检测需要采用非常规方法。其中一种方法是将培养温度设定为30摄氏度，与之形成对比的是更常用的35摄氏度。为了确定仅使用一个温度时会遗漏的MRSA分离株的百分比，我们通过在30摄氏度和35摄氏度下进行琼脂稀释，评估了2397株金黄色葡萄球菌分离株的甲氧西林耐药性和敏感性。在临床分离株中，93%在两个温度下的甲氧西林最低抑菌浓度（MIC）相匹配。另外6.8%（162株）在30摄氏度和35摄氏度下显示出不同的MIC，其中162株中的60株（占所有研究分离株的2.5%）在30摄氏度时对甲氧西林耐药，但在35摄氏度时敏感（温度差异型MRSA）。在35摄氏度下测量的其他抗菌药物的MIC显示，这些温度差异型MRSA分离株具有不同寻常的敏感性模式。与之前报道的35摄氏度下MRSA对红霉素、克林霉素、庆大霉素和四环素耐药不同，温度差异型MRSA分离株对这些药物敏感。当仅使用一个培养温度时，这种耐药模式可能有助于识别可疑的MRSA分离株。
