中台灣兩區域教學醫院之抗甲氧苯青黴素金黃色葡萄球菌分子流行病學探討

Molecular Epidemiology of Methicillin Resistant Staphylococcus aureus Bloodstream Isolates in Central Taiwan

研究目的:本研究以分子生物學方式分析來自兩家中部區域醫院從血液檢體所分離抗甲氧苯青黴素金黃色葡萄球菌(MRSA)菌株,透過分析抗藥性卡莢基因型、A蛋白基因型以及多點位基因序列分析比較不同年份所採集到的MRSA菌株在抗藥性以及基因型分布是否隨時間改變。
檢體來源與方法:檢體來源為彰化秀傳醫院與彰濱秀傳醫院自2007到2013年所凍存血液感染的MRSA菌株。除了針對臨床12種抗生素抗藥性分析外,還利用分子技術分析抗藥性卡莢基因型、A蛋白基因型、多點位基因序列分析以及兩個重要金黃色葡萄球菌的生物標誌基因預探討兩家醫院MRSA血液感染菌株的分子型別是否隨著時間發生型別改變。
實驗結果:研究MRSA菌株從2007到2013年共409株,依據菌株SCCmec分型及Spa分型的結果進一步挑選121株進行MLST,主要依序為t037-SCCmecIII-ST239(21.5%),其次為t002-SCCmecII-ST5(14%),及t437-SCCmecIV-ST59(7.4%),及其他分型。毒性基因的探討方面主要以第VT型所佔的比率最高(82.2%)。在探討促使菌株黏附鼻腔使得移生能力增加主要以SCCmectypeIII為主所佔比率(96.2%)。
結論:若能發展出適合且快速精準的檢測方式並持續監控這三種主要型別MRSA變化可以提供院內感染的控制參考與早期疾病治療依據,為本研究最終的努力目標。

Aim: Methicillin-resistant Staphylococcus aureus (MRSA) is methicil-lin resistant Staphylococcus aureus. It was discovered in 1961. MRSA can exist in various parts of the body, including the nose and skin. Carriers are the main disseminators of nosocomial infections caused by Staphylococcus aureus commonly, accounting for about about 70% are MRSA. Nosocomial infections and Gram-positive resistant bacteria are important causes of serious medical problems.
Methods: A total of 409 clinical MRSA bloodstream isolates from Show Chwan Memorial Hospital and Chang Bing Show Chwan Memorial Hospital from 2007-2013 were determined to exhibit three molecular types (SCCmec types, spa-type and MLST), carriage of Panton-Valentine leukocidin (PVL) and sasX genes and susceptibilities to 12 non-beta-lactam antimicrobial agents.
Results: According the genotype results of SCCmec types and Spa types, we selected 121 strains to analyze the sequence types. Three major genotypes, which included t037-SCCmecIII-ST239 (21.5%), t002-SCCmecIV-ST5 (14%) and t437-SCCmecII-ST59 (7.4%) prevailed in the two hospitals. PVL and sasX genes were respectively carried by SCCmec VT (82.2%) and ST239-SCCmec III (96.2%) with high frequencies, but other genotypes were rarely detected.
Conclusion: The aim of this study was to investigate two different regions of the separation of MRSA bloodstream infections in hospitals. We examined the distribution of genotypes and developed a rapid screening method for long-term monitoring of the epidemiology and ecology of the bacteria evolution trend.