Kao Kuo-Chin, Chen Chun-Bing, Hu Han-Chung, Chang Hui-Ching, Huang Chung-Chi, Huang Yhu-Chering
Department of Thoracic Medicine and Respiratory Therapy, Chang Gung University College of Medicine, Linkou (K-CK, H-CH, C-CH); Department of Dermatology, Chang Gung University College of Medicine, Keelung (C-BC); Department of Pediatrics, Chang Gung University College of Medicine, Chang Gung Memorial Hospital, Linkou, Taiwan (H-CC, Y-CH).
Medicine (Baltimore). 2015 Jul;94(28):e1100. doi: 10.1097/MD.0000000000001100.
Methicillin-resistant Staphylococcus aureus (MRSA) is a common and important cause of colonization and infection in medical intensive care units (ICU). The aim of this study was to assess association factors between MRSA nasal colonization and subsequent infections in medical ICU patients by clinical investigation and molecular genotyping. A prospective cohort observational analysis of consecutive patients admitted to medical ICUs between November 2008 and May 2010 at a tertiary teaching hospital were included. To detect MRSA colonization, the specimens from the nares were obtained within 3 days of admission to the ICU and again 1 week following admission to the ICU. Genetic relatedness for colonized and clinical isolates from each study patient with MRSA infection were analyzed and compared. A total of 1266 patients were enrolled after excluding 195 patients with already present MRSA infections. Subsequent MRSA infection rates were higher in patients with nasal colonization than in those without (39.1% versus 14.7%, respectively). Multivariate Poisson regression analysis demonstrated that nasal MRSA colonization (relative risk [RR]: 2.50; 95% confidence interval [CI]: 1.90-3.27; P < 0.001) was independent predictors for subsequent MRSA infections. History of tracheostomy, however, was a protective predictor in all patients (RR: 0.38; 95% CI: 0.18-0.79; P = 0.010) and in patients with MRSA nasal colonization (RR: 0.22; 95% CI: 0.55-0.91; P = 0.037). Molecular genetics studies revealed that most MRSA isolates were healthcare-associated clones and that nasal and clinical isolates exhibited up to 75% shared identity. Methicillin-resistant S. aureus nasal colonization was significantly associated with subsequent MRSA infection among medical ICU patients. Previous MRSA infection was associated with subsequent MRSA infections, and history of tracheostomy associated with reducing this risk. Most MRSA isolates were healthcare-associated strains that were significantly correlated between nasal and clinical isolates.
耐甲氧西林金黄色葡萄球菌（MRSA）是医疗重症监护病房（ICU）中定植和感染的常见且重要原因。本研究旨在通过临床调查和分子基因分型评估医疗ICU患者中MRSA鼻腔定植与随后感染之间的相关因素。纳入了对2008年11月至2010年5月在一家三级教学医院医疗ICU收治的连续患者进行的前瞻性队列观察分析。为检测MRSA定植，在入住ICU的3天内及入住ICU 1周后从鼻孔获取标本。对每位MRSA感染研究患者的定植和临床分离株的遗传相关性进行分析和比较。排除195例已存在MRSA感染的患者后，共纳入1266例患者。鼻腔定植患者的后续MRSA感染率高于未定植患者（分别为39.1%和14.7%）。多变量泊松回归分析表明，鼻腔MRSA定植（相对风险[RR]：2.50；95%置信区间[CI]：1.90 - 3.27；P＜0.001）是后续MRSA感染的独立预测因素。然而，气管切开史在所有患者中（RR：0.38；95% CI：0.18 - 0.79；P = 0.010）以及在MRSA鼻腔定植患者中（RR：0.22；95% CI：0.55 - 0.91；P = 0.037）是一个保护性预测因素。分子遗传学研究表明，大多数MRSA分离株是与医疗保健相关的克隆株，鼻腔和临床分离株显示出高达75%的相同性。医疗ICU患者中，耐甲氧西林金黄色葡萄球菌鼻腔定植与随后的MRSA感染显著相关。既往MRSA感染与随后的MRSA感染相关，气管切开史与降低这种风险相关。大多数MRSA分离株是与医疗保健相关的菌株，鼻腔和临床分离株之间存在显著相关性。
