Methicillin抗藥性金黃色葡萄球菌之分子流行病學及抗生素抗藥性分析

Methicillin抗藥性金黃色葡萄球菌(methicillin-resistant Staphylococcus aureus, MRSA) 是院內及社區感染的主要致病菌，MRSA對methicillin抗藥性的產生主要是因金黃色葡萄球菌獲得外來基因複合體staphylococcal cassette chromosome mec (SCCmec)。SCCmec第I、II、III型多為院內感染型，SCCmec第IV、V型多為社區感染型。社區感染型的MRSA通常對大部分的非 β-lactam類藥物有較好的感受性，而且都帶有一毒素因子Panton–Valentine leukocidin (PVL)。本實驗將中山醫學大學附設醫院所分離出的229株MRSA菌株，利用聚合酶連鎖反應觀察其SCCmec分型、PVL基因攜帶與否，進一步利用肉湯微量稀釋法做藥物感受性試驗，並分析菌株來源的基本資料，以了解院內或社區感染型MRSA菌株之分佈及感染的流行情況。結果顯示，229株MRSA菌株，SCCmec第II型有19.65%、第III型18.78%、第IV、V型分別為31.00%、30.57%；以病人平均年齡來看，18歲以下這一族群，有84.38% 都是屬於CA-MRSA (SCCmec第IV、V型)；SCCmec第II、III型大部份從住院病人所分離；而抗生素感受性的表現，SCCmec第IV、V型對大部分非β-lactam類抗生素有較高的敏感性。另外，229株MRSA菌株只有59株 (25.76%) 帶有PVL毒素因子，除了一株是SCCmec第IV型、其餘都是第V型；帶有PVL毒素因子的病人平均年齡都較小 (P<0.001) 之外，大部份是從門診或急診所分離出來的(P<0.001)；而抗生素感受性的表現，攜帶PVL的MRSA菌株對大部分非β-lactam類抗生素有較高的敏感性(P<0.001)。本次實驗結果與其它醫院所做的結果相近，由這些資料希望可幫助醫療人員對MRSA流行病學及抗藥性之瞭解，做為治療方式及用藥選擇之參考。

關鍵字

金黃色葡萄球菌；抗藥性分析

並列摘要

Methicillin-resistant S. aureus (MRSA) is a major human pathogen that causes both hospital- and community-acquired infection. MRSA resistant to methicillin is caused by the staphylococcal cassette chromosome mec (SCCmec). HA-MRSA (hospital-acquired) harbors SCCmec types I, II, III, and CA-MRSA (community-acquired) harbors SCCmec type IV or V. In addition, CA-MRSA is more susceptible to non β-lactam antibiotics and is associated with the gene encoding Panton–Valentine leukocidin (PVL). In this study, used a PCR assay classifying 229 MRSA isolates described SCCmec types, detecting PVL gene, determine the antibiotic susceptibility by broth microdilution method, and analyzed patients characteristics. The MRSA SCCmec types were as follows: 19.65% was SCCmec type II, 18.78% was SCCmec type III, 31.00% was SCCmec type IV, 30.57% was SCCmec type V; Patients ≤18 years of age most harbored SCCmec type IV or V (84.38%); MRSA carrying SCCmec type II or III was more likely to occur in hospitalization patients; Most HA-MRSA (SCCmec type II, III) was resistant to non β-lactam antibiotics. In addition, 59 PVL-positive MRSA isolates were classified as CA-MRSA (one was SCCmec type IV, anothers were SCCmec type V), and the mean age of patients with PVL-positive MRSA isolates were significantly lower than of patients with PVL-negative MRSA isolates (P<0.001). PVL-positive MRSA isolates were more likely to occur in OPD or ER patients (P<0.001), and were more susceptible to non β-lactam antibiotics (P<0.001). In conclusion, these findings are similar to previous studies of the genetic characteristics MRSA. This information may be serve as a useful tool for preventing and controlling infections caused by MRSA isolates.

並列關鍵字

Staphylococcus aureus ； antimicrobial susceptibility test

參考文獻

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Methicillin抗藥性金黃色葡萄球菌之分子流行病學及抗生素抗藥性分析

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