加護病房環境Methicillin抗藥性金黃色葡萄球菌污染與病人移生之關係

Relationship Between Environmental Contamination and Patients’ Acquisition of Methicillin-resistant Staphylococcus aureus

從1960年代至今methicillin抗藥性金黃色葡萄球菌(methicillin-resistant Staphylococcus aureus; MRSA)，已成為歐美及台灣院內感染主要致病菌，其中加護病房被證實為MRSA傳播的主要場所。本研究之目的在探討加護病房非病人直接接觸的環境中，被MRSA污染之比率及與病人得到MRSA移生的關係。採橫斷式研究，在南部某醫學中心內科加護病房，採取環境（電腦、電話、病人呼叫系統、病歷、水龍頭開關、超音波儀器、磅秤）及病人鼻腔檢體，並進行菌株分型比對。環境清潔前後各收集103 個檢體，結果發現清潔前有2.9%(3/103) 環境檢體受MRSA污染(病室內電腦螢幕按鍵、病室外電腦鍵盤及超音波儀器開關)，清潔後無環境檢體受污染；共篩檢9位病人之鼻腔，其中22.2%(2/9) 為MRSA鼻腔移生，在2位MRSA 鼻腔移生者中，1 (11.1%) 人臨床已有MRSA感染。針對2位醫師及4位護理人員進行鼻腔採檢，未發現有MRSA帶菌；對醫護人員出病室後、洗手後的手部，及配戴之6個識別證、3個眼鏡與2個傳呼器進行物品採檢，共23個檢體，皆無MRSA的污染。以脈衝式電泳分析法進行MRSA分型比對，3個環境MRSA菌株及2個病人MRSA菌株，基因分型皆屬不同亞型。本研究發現非病人直接接觸之環境，僅少數受MRSA污染，與病人移生菌株無相關性。本加護病房推行環境清潔策略及洗手運動已一段時日，推測可能是環境MRSA污染率低的原因之一。因此加護病房工作人員應持續洗手及落實環境清潔工作。

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the important pathogens of nosocomial infections worldwide. Intensive care units (ICUs) play a major role in the spread of MRSA infection in hospitals. The purpose of this study was to determine the relationship between environmental contamination with MRSA and patients’ acquisition of MRSA. A prospective, cross-sectional study was conducted on December 6, 2006 at a 9-bed medical ICU facility in southern Taiwan. The environmental samples, including computer system, telephone, calling system, drinking fountain, weighing scale, ultrasonic detector, handle of the faucet, disinfectant container, patients’ files, and the healthcare professionals’ hands, pagers, identification cards, and glasses, were screened for MRSA. Patients and health professionals were screened by checking nasal swabs for MRSA carriage. Samples obtained from the environment, patients, and healthcare professionals were then typed using pulsed-field gel electrophoresis. We collected 103 samples both before and after cleaning the environment. MRSA was isolated from 3 (2.9%) of the 103 environmental samples obtained before cleaning, i.e., samples from a computer switch, keyboard, and an ultrasonic detector switch. After cleaning the environment, no MRSA was found in the ICU environment. Two (22.2%) of the 9 patients had MRSA colonization, and 1 had MRSA infection. None of the 2 doctors and 4 nurses had nasal MRSA colonization, nor was MRSA colonization observed on the healthcare professionals’ hands, pagers, ID cards, and glasses. The 5 MRSA isolates showed different molecular profiles in pulsed-field gel electrophoresis. Although there was no genetic relationship between environmental and patient isolates, the study reveals that MRSA contamination is present in the hospital environment; this may be eliminated by routine cleaning of the ICU and compliance to hand hygiene practices.