社區Oxacillin 抗藥性金黃色葡萄球菌感染或移生之流行病學分析

Oxacillin抗藥性金黃色葡萄球菌(oxacillin resistant Staphylococcus aureus; ORSA)是院內感染主要致病菌之一，台灣近十年來社區oxacillin抗藥性金黃色葡萄球菌(community-onset Staphylococcus aureus ; CO-ORSA)盛行率明顯的增加，這些CO-ORSA不像醫院的ORSA感染者有明顯的指標因子。本研究為了解南部某醫學中心之CO-ORSA感染或移生的情形、可能危險因子和抗生素感受性表現，採病例對照研究，對象來自2003年1月至10月間，門、急診或住院未滿48小時之病患，其細菌培養為ORSA或OSSA者。共收集個案及對照組各158人, 進行統計分析。結果發現：CO-ORSA最常發生感染或移生的部位，以皮膚軟組織(44.3%)為最常見、傷口(17.7%)次之、三為血流感染(15.2%)，和CO-OSSA組比較，無統計學上的差異(p>.05)。CO-ORSA者平均年齡52.9±18.6歲、有39.5%(62/157)需要使用輔助器(如柺杖或助行器)或長期臥床、平均同住人口數4.8±1.5人、有8.3%(13/157)住在長期照護機構、過去一年內平均門急診次數50.6±35.9人次、平均住院次數1.2±1.7人次,相較於CO-OSSA者，具有統計學上的差異（p＜.05）。門急診次數和住院次數愈多，呈現dose-response effect。與CO-OSSA組相比，CO-ORSA者有較多惡性血液腫瘤(24.1%)、腦血管病變(10.1%)、慢性鼻病(7.0%)等慢性病（p＜.05）;糖尿病、慢性腎衰竭、慢性皮膚病和呼吸道疾病，則無統計學上的差異(p>.05)。有較多的CO-ORSA者在過去三個月內曾接受抗生素、手術、導尿管、鼻胃管等治療（p＜.05）。以logistic regression分析比較，居住在長期照護機構、行動不便、腦血管病變、慢性鼻病、曾經住院與否和抗生素使用，是CO-ORSA感染或移生之獨立危險因子。大部分的CO-ORSA對抗生素的感受性普遍降低，包括co-trimoxazole(62%)、chloramphenicol(61%)、netilmicin(61%)、gentamicin(59%)、cefazolin(48%)、amoxicillin/clavulanate(48%)、ampicillin/sulbactam(47%)、clidamycin(21%)。25位皮膚軟組織或傷口感染CO-ORSA者，在治療的過程中仍可持續帶菌長達六個月之久。研究結果顯示：對於皮膚軟組織或傷口曾經感染ORSA，有行動不便、慢性鼻病、腦血管病變、最近一年內曾經住院或近三個月內曾經使用抗生素者，在個案再次入院時，醫院應儘早實施感染管制措施，以降低ORSA在醫院中交互感染的發生。

關鍵字

金黃色葡萄球菌；抗藥性；流行病學

並列摘要

Oxacillin-resistant Staphylococcus aurues (ORSA) is one of the important nosocomial pathogens .The prevalence of community-onset ORSA (CO-ORSA) in Taiwan has increased markedly in the past 10 years. CO-ORSA patients had no significant predisposing factors which is different from the nosocomial ORSA. A retrospective case-control comparison study of the clinical characteristics, risk factors and antibiotics susceptibility for CO-ORSA compared with CO-OSSA (community-onset oxacillin-susceptible Staphylococcus aurue ) infection or colonization in adult outpatients was performed from January 2003 to October 2003 at Kaoshiung Medical University Hospital. One hundred and fifty eight CO-ORSA and 158 CO-OSSA infected patients were enrolled in this study for comparison and analysis. The results show that the most common site of CO-ORSA infection or colonization was skin and soft tissue (44.3%), following by wound (17.7%) and blood stream (15.2%). The percentage of patients infected with CO-OSSA was similar to the CO-ORSA. The average age of CO-ORSA group were 52.9± 18.6 years, and 39.5% (62/157) of them need walker or were bed-ridden. The average amount of people who living together were 4.8 ±1.5,and 8.3 % of them lived in LCTFs; The average times of visiting OPD and / or ER were 50.6 ±35.9. The frequencies of hospitalization were 1.2 ±1.7 , which had significant difference compared to CO-OSSA group. It shows a significant dose-effect response in the number of admissions or OPD/ER visit in group of CO-ORSA. In comparing with CO-OSSA patients , CO-ORSA patients had higher percentage of malignancy (24.1%), cerebral-vascular accidents (10.1%) and chronic nasal disease ( 7.0%).Use of antibiotics, surgery, foley catheters and nasal-gastric tube in the previous 3 months were commonly seen in patients with CO-ORSA infected which is statistically significant (p< .05). After Logistic regression analysis, the independent risk factors for developing CO-ORSA were residing in LCTF, disabilities, chronic nasal disease , cerebral-vascular accidents, use of antibiotics and previous hospitalization. Most of the isolated CO-ORSA had a low susceptibility against most antibiotics, including co-trimoxazole (62%), chloramphenicol (61%), netilmicin (61%) , gentamicin (59%), amoxicillin/clavulanate (48%), cefazolin (48%), ampicillin/sulbactam (47%) and clindamycin (21%). During the process of medical treatment, CO-ORSA can be carried for 6 months. According to the study, the patient of skin or soft tissue ORSA infection, precautions of infection control should be performed as early as possible to reduce the rate of cross- infection when they admitted again.