探討外科加護病房患者抗 Methicillin 金黃色葡萄球菌移生盛行率與其相關因素

Prevalence and Risk Factors of MRSA Colonization of Patients in Surgical Intensive Care Units

背景：抗 Methicillin 金黃色葡萄球菌（methicillin-resistant Staphylococcus aureus, MRSA）之盛行率依地區性與國家不同而有差異，患者感染 MRSA 常併發敗 血症、心內膜炎、肺炎及皮膚軟組織感染等病症，而延長個案的住院天數、增加醫療費用與死亡率。主動監測培養（Active Surveillance Culture, ASC） 可早期發現 MRSA 之移生患者，早期執行接觸隔離，以預防後續的感染發生。因此，本研究目的是探討外科加護病房患者之 MRSA 移生盛行率與其相 關因素。

研究方法：本研究為橫斷性研究設計，於某區域教學醫院之成人外科加護病房收集資料，針對急診入住 48 小時內的病人執行鼻腔 ASC 之 MRSA 菌株的篩檢與 菌株培養。並收集個案有關 MRSA 鼻腔移生之相關因素。

研究結果：外科加護病房患者於 48 小時內 MRSA 鼻腔移生盛行率為 10.5%，其相關 因素在單變量分析顯示入院前住所、疾病嚴重度分數（Acute Physiology and Chronic Health Evaluation Ⅱ, APACHE Ⅱ）、動脈血液氣體分析 pH 值異 常、血球容積比異常、血液中白血球計數過高等變項，與 MRSA 鼻腔移生有顯著相關性；在多變量分析，只有動脈血液氣體分析 pH 值異常與血球容積 比異常二個變項，對 MRSA 鼻腔移生具有解釋力。

討論與結論：醫護人員應積極評估入住 ICU 患者是否為 MRSA 鼻腔移生之高危險群（如動脈血液氣體分析 pH 值異常者、血球容積比異常者），並對此高危險群 患者提早執行接觸隔離措施，以期降低 MRSA 移生所造成的後續感染。

 

Background: The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) varies for different regions and countries. Data from Taiwan’s nosocomial infection surveillance system indicate that the density of MRSA infection for drug-resistant strains in the intensive care units (ICU) of medical centers and regional hospitals was once as high as 4.7‰-6.0‰. MRSA often has such complications as sepsis, endocarditis, pneumonia and skin and soft tissue infections, which prolong hospitalization days and increase medical costs and mortality. Active nasal screening can detect patients with early colonization so that the early contact isolation of patients can be implemented to prevent subsequent MRSA infection. Therefore, the purpose of this study is to investigate the MRSA nasal colonization rate and its related factors within 48 hours of emergency patients being admitted to surgical intensive care units.

Methods: Secondary data analysis was used. The database used was designed for cross-sectional studies. Data were collected from adult surgical intensive care units in a regional teaching hospital. MRSA nasal screening was performed by administering Active Surveillance Culture (ASC) to emergency patients within 48 hours of admission, and the MRSA strain was cultured after the specimen was obtained. The relevant factors related to MRSA nasal colonization of individual cases were collected by means of tracking medical records. The data obtained were verified by descriptive statistics, chi-square tests, multivariate logistic regression analysis, etc.

Results: The study showed that the MRSA nasal colonization rate was 10.5% within 48 hours of admission to intensive care units. Univariate analysis showed that the pre-hospital residence, Acute Physiology and Chronic Health Evaluation II (APACHE II), abnormal pH value in the arterial blood gas analysis, abnormal hematocrit ratio, excessively high count of white blood cells in the blood and other variables had significant correlations with MRSA nasal colonization. In multivariate analysis, only two variables, namely, abnormal pH value in the arterial blood gas analysis and abnormal hematocrit ratio were significantly correlated with MRSA nasal colonization.

Discussion and Conclusions: The results of this study show that for the patients in intensive care units, their pre-hospital residences, APACHE II scores, arterial blood gas analysis pH values, hematocrit ratios, and blood white blood cell counts are the risk factors for ASC MRSA nasal colonization. Medical staff should actively assess whether ICU patients are in a high risk group for MRSA nasal colonization, and perform early contact isolation measures for such patients so as to reduce infection caused by MRSA colonization.