主动监测鉴定的鼻腔定植携带耐甲氧西林金黄色葡萄球菌（MRSA）USA300 型菌株患者的流行率。

Prevalence of USA300 strain type of methicillin-resistant Staphylococcus aureus among patients with nasal colonization identified with active surveillance.

机构信息

Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, USA.

出版信息

Infect Control Hosp Epidemiol. 2010 May;31(5):469-75. doi: 10.1086/651672.

DOI:10.1086/651672

PMID:20225966

Abstract

BACKGROUND

USA300 is the most prevalent strain type of community-acquired methicillin-resistant Staphylococcus aureus (MRSA), but the proportion of patients colonized with USA300 strains and their risk for infection are largely unknown.

OBJECTIVE

To determine the prevalence of USA300 strains among MRSA nasal colonizing isolates in our hospital, to identify risks for USA300 nasal colonization, and to determine risks of developing infection for nasally colonized patients.

METHODS

Retrospective cohort study of patients found to be nasally colonized with MRSA through active surveillance at a tertiary care hospital from January 2005 through December 2007. MRSA isolates were identified as USA300 or non-USA300. Risks for colonization and infection were identified with logistic regression.

RESULTS

Among 1,306 MRSA nasal isolates, 307 (24%) were USA300 strains, and this proportion significantly increased over time (17.4% in 2005 and 26.7% in 2007; P = .003). African American race was an independent risk for USA300 nasal colonization (odds ratio [OR], 1.81 [95% confidence ratio {CI}, 1.38-2.38]). Older age (OR, 0.97 [95% CI, 0.96-0.98]) and female sex (OR, 0.74 [95% CI, 0.56-0.97]) decreased risk. Among nasally colonized patients, 238 (18.2%) developed infection. Increased length of stay (OR, 1.03 [95% CI, 1.01-1.06]) independently increased risk for infection among patients nasally colonized with USA300 MRSA, and female sex decreased risk (OR, 0.48 [95% CI, 0.24-0.95]). Increased length of stay (OR, 1.03 [95% CI, 1.02-1.04]) and treatment in an intensive care unit (OR, 1.64 [95% CI, 1.10-2.44]) independently increased risk for infection among patients nasally colonized with non-USA300 MRSA, and female sex decreased risk (OR, 0.67 [95% CI, 0.47-0.94]).

CONCLUSION

The proportion of MRSA nasally colonized patients with USA300 strains significantly increased during the study, and risks included African American race. Strain type had no significant effect on the proportion of patients who developed infection, and risk factors for infection were similar.

摘要

背景

USA300 是社区获得性耐甲氧西林金黄色葡萄球菌（MRSA）中最普遍的菌株类型，但鼻腔定植 USA300 菌株的患者比例及其感染风险在很大程度上尚不清楚。

目的

确定我院鼻腔定植 MRSA 患者中 USA300 菌株的流行率，确定 USA300 鼻腔定植的风险，并确定鼻腔定植患者发生感染的风险。

方法

对 2005 年 1 月至 2007 年 12 月在一家三级保健医院通过主动监测发现的鼻腔定植 MRSA 的患者进行回顾性队列研究。MRSA 分离株被鉴定为 USA300 或非 USA300 株。使用逻辑回归确定定植和感染的风险。

结果

在 1306 例鼻腔 MRSA 分离株中，有 307 株（24%）为 USA300 株，并且该比例随时间推移显著增加（2005 年为 17.4%，2007 年为 26.7%；P=0.003）。非裔美国人种族是 USA300 鼻腔定植的独立危险因素（比值比[OR]，1.81[95%置信区间{CI}，1.38-2.38]）。年龄较大（OR，0.97[95%CI，0.96-0.98]）和女性（OR，0.74[95%CI，0.56-0.97]）降低了风险。在鼻腔定植的患者中，有 238 例（18.2%）发生了感染。住院时间延长（OR，1.03[95%CI，1.01-1.06]）是 USA300 定植的 MRSA 鼻腔定植患者感染的独立危险因素，而女性降低了风险（OR，0.48[95%CI，0.24-0.95]）。住院时间延长（OR，1.03[95%CI，1.02-1.04]）和在重症监护病房治疗（OR，1.64[95%CI，1.10-2.44]）是 USA300 定植的非-USA300 定植 MRSA 患者感染的独立危险因素，而女性降低了风险（OR，0.67[95%CI，0.47-0.94]）。