Jenkins Timothy C, McCollister Bruce D, Sharma Rohini, McFann Kim K, Madinger Nancy E, Barron Michelle, Bessesen Mary, Price Connie S, Burman William J
Division of Infectious Diseases, Denver Health, CO 80204, USA.
Infect Control Hosp Epidemiol. 2009 Mar;30(3):233-41. doi: 10.1086/595963.
To describe the epidemiology of bloodstream infection caused by USA300 strains of methicillin-resistant Staphylococcus aureus (MRSA), which are traditionally associated with cases of community-acquired infection, in the healthcare setting.
Retrospective cohort study.
Three academically affiliated hospitals in Denver, Colorado.
Review of cases of S. aureus bloodstream infection during the period from 2003 through 2007. Polymerase chain reaction was used to identify MRSA USA300 isolates.
A total of 330 cases of MRSA bloodstream infection occurred during the study period, of which 286 (87%) were healthcare-associated. The rates of methicillin resistance among the S. aureus isolates recovered did not vary during the study period and were similar among the 3 hospitals. However, the percentages of cases of healthcare-associated MRSA bloodstream infection due to USA300 strains varied substantially among the 3 hospitals: 62%, 19%, and 36% (P<.001) for community-onset cases and 33%, 3%, and 33% (P=.005) for hospital-onset cases, in hospitals A, B, and C, respectively. In addition, the number of cases of healthcare-associated MRSA bloodstream infection caused by USA300 strains increased during the study period at 2 of the 3 hospitals. At each hospital, USA300 strains were most common among cases of community-associated infection and were least common among cases of hospital-onset infection. Admission to hospital A (a safety-net hospital), injection drug use, and human immunodeficiency virus infection were independent risk factors for healthcare-associated MRSA bloodstream infection due to USA300 strains.
The prevalence of USA300 strains among cases of healthcare-associated MRSA bloodstream infection varied dramatically among geographically clustered hospitals. USA300 strains are replacing traditional healthcare-related strains of MRSA in some healthcare settings. Our data suggest that the prevalence of USA300 strains in the community is the dominant factor affecting the prevalence of this strain type in the healthcare setting.
描述在医疗环境中，由美国300型耐甲氧西林金黄色葡萄球菌（MRSA）引起的血流感染的流行病学特征，传统上该菌株与社区获得性感染病例相关。
回顾性队列研究。
科罗拉多州丹佛市的三家学术附属医院。
回顾2003年至2007年期间金黄色葡萄球菌血流感染病例。采用聚合酶链反应鉴定美国300型MRSA分离株。
研究期间共发生330例MRSA血流感染病例，其中286例（87%）与医疗保健相关。研究期间，所分离出的金黄色葡萄球菌菌株的耐甲氧西林率没有变化，且在这三家医院中相似。然而，美国300型菌株导致的与医疗保健相关的MRSA血流感染病例的百分比在这三家医院中差异很大：A、B、C医院社区发病病例分别为62%、19%和36%（P<0.001），医院发病病例分别为33%、3%和33%（P=0.005）。此外，在研究期间，三家医院中有两家医院由美国300型菌株引起的与医疗保健相关的MRSA血流感染病例数量增加。在每家医院，美国300型菌株在社区相关感染病例中最常见，在医院发病感染病例中最不常见。入住A医院（一家安全网医院）、注射吸毒和感染人类免疫缺陷病毒是美国300型菌株导致的与医疗保健相关的MRSA血流感染的独立危险因素。
在地理位置集中的医院中，美国300型菌株在与医疗保健相关的MRSA血流感染病例中的流行率差异很大。在一些医疗环境中，美国300型菌株正在取代传统的与医疗保健相关的MRSA菌株。我们的数据表明，社区中美国300型菌株的流行率是影响该菌株类型在医疗环境中流行率的主要因素。
