Selvey L A, Whitby M, Johnson B
Communicable Diseases Branch, Queensland Health, Brisbane, Australia.
Infect Control Hosp Epidemiol. 2000 Oct;21(10):645-8. doi: 10.1086/501707.
To determine the comparative virulence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S aureus (MSSA) by consideration of predisposing factors and outcomes in patients infected with these organisms in the healthcare setting.
Analysis of an historical cohort of 504 bacteremic patients (316 MSSA and 188 MRSA), examining factors associated with mortality.
A 916-bed, university-affiliated, tertiary referral hospital.
Risk factors for the development of MRSA include male gender, admission due to trauma, immunosuppression, presence of a central vascular line or an indwelling urinary catheter, and a past history of MRSA infection. Overall mortality was 22%. Death due to bacteremia was significantly greater in the MRSA group (risk ratio, 1.68; P<.05), although these patients were not found to be more likely to die due to underlying disease during treatment of bacteremia. In those patients who recovered from bacteremia, no significant differences for the outcome of death could be determined between the MRSA and MSSA groups.
There is a general consensus in the published literature that MRSA bacteremia is more likely to be associated with death, and we confirm this conclusion. However, in contrast to other studies, our MRSA cohort does not appear to be more at risk of death due to underlying disease during treatment for bacteremia. Similarly, the general consensus that MRSA patients have an increased overall mortality was not confirmed in our study. Differences in comorbidities of patients may provide some explanation of these conflicting results, while an alternate explanation is that MRSA strains are more virulent than MSSA in some centers. Perhaps the most plausible explanation is that treatment is provided earlier and in a more aggressive fashion in some centers, leading to an overall lower mortality rate in all staphylococcal bacteremias in these institutions.
通过考虑医疗环境中感染这些病原体的患者的易感因素和结局，确定耐甲氧西林金黄色葡萄球菌（MRSA）和甲氧西林敏感金黄色葡萄球菌（MSSA）的相对毒力。
对504例菌血症患者（316例MSSA和188例MRSA）的历史队列进行分析，研究与死亡率相关的因素。
一家拥有916张床位的大学附属医院，三级转诊医院。
MRSA感染的危险因素包括男性、因创伤入院、免疫抑制、存在中心血管导管或留置导尿管以及既往有MRSA感染史。总体死亡率为22%。MRSA组因菌血症导致的死亡显著更高（风险比，1.68；P<0.05），尽管在菌血症治疗期间未发现这些患者因基础疾病死亡的可能性更高。在那些从菌血症中康复的患者中，MRSA组和MSSA组之间在死亡结局方面未发现显著差异。
已发表的文献中普遍认为MRSA菌血症更可能与死亡相关，我们证实了这一结论。然而，与其他研究不同的是，我们的MRSA队列在菌血症治疗期间似乎没有因基础疾病而有更高的死亡风险。同样，我们的研究未证实MRSA患者总体死亡率增加这一普遍观点。患者合并症的差异可能对这些相互矛盾的结果提供一些解释，另一种解释是在某些中心MRSA菌株比MSSA更具毒力。也许最合理的解释是在某些中心治疗更早且更积极，导致这些机构中所有葡萄球菌菌血症的总体死亡率更低。
