Baddour L M, Tayidi M M, Walker E, McDevitt D, Foster T J
Department of Medicine, University of Tennessee Medical Center at Knoxville 37920-6999.
J Med Microbiol. 1994 Oct;41(4):259-63. doi: 10.1099/00222615-41-4-259.
A sensitive rat endocarditis model which employed relatively small inocula (< or = 10(4) cfu) was used to examine the role of coagulase in the pathogenesis of infection. Rats with indwelling, intracardiac catheters were challenged intravenously with three strains of Staphylococcus aureus. The virulence of a coagulase-positive parental strain DU5808 was compared in terms of its ID50 for resected vegetations and catheters to that of two coagulase-negative mutant strains (DU5809 and DU5814) which had undergone site-specific mutagenesis. Confidence intervals of infection rates were calculated and comparisons were performed of weights of infected vegetations, bacterial concentrations in vegetations and early mortality rates. From these virulence parameters, it was concluded that there were no differences in virulence among the three strains. The results from this investigation support the previous findings in mouse models of subcutaneous infection and mastitis, which indicated that coagulase production by S. aureus does not appear to function as a virulence factor. Together, these data refute the longheld belief that coagulase is important in the pathogenesis of infection and indicate that other markers of virulence must be operative in diseases caused by the enduring pathogen S. aureus.
一种采用相对小接种量（≤10⁴ cfu）的敏感大鼠心内膜炎模型用于研究凝固酶在感染发病机制中的作用。对留置心内导管的大鼠静脉注射三株金黄色葡萄球菌。将凝固酶阳性亲代菌株DU5808的毒力与其ID50（针对切除的赘生物和导管）与两株经过位点特异性诱变的凝固酶阴性突变菌株（DU5809和DU5814）进行比较。计算感染率的置信区间，并对感染赘生物的重量、赘生物中的细菌浓度和早期死亡率进行比较。从这些毒力参数得出结论，这三株菌株的毒力没有差异。这项研究的结果支持了先前在皮下感染和乳腺炎小鼠模型中的发现，即金黄色葡萄球菌产生的凝固酶似乎不作为毒力因子起作用。总之，这些数据驳斥了长期以来认为凝固酶在感染发病机制中很重要的观点，并表明在由持久性病原体金黄色葡萄球菌引起的疾病中，其他毒力标志物一定起作用。
