自皮膚及軟組織感染分離之金黃色葡萄球菌特性探討

Abstract

金黃色葡萄球菌(Staphylococcus aureus, S. aureus)屬於人體鼻腔和皮膚的常在菌叢，主要會引起人類包括皮膚、軟組織、 肺炎、心內膜炎以及菌血症等感染，依其對於methicillin抗藥與否可以分成methicillin-resistant S. aureus及methicillin-susceptible S. aureus，以感染源於可區分為healthcare-associated及community-associated ，在臨床上S. aureus為造成皮膚及軟組織感染的主要來源，而其感染後約有三成的病人有復發感染的情況，說明病人無法因先前的感染進而對於S. aureus產生良好的免疫。因此本實驗欲收集臨床上來自皮膚及軟組織感染之S. aureus探討其抗藥性及毒力等特性。 本實驗共收集來自急診及門診菌株129株，及病房91株，其中MRSA的比例分別是60%以及68%。來源為皮膚軟組織感染有172株。MRSA當中來自急診及門診的菌株其藥物敏感性較病房好，但MSSA來源對藥物敏感性的差異不大。我們針對皮膚軟組織感染菌株進行spa type 分析，其中16%為t437、12%為t037、8%為t008、4%為t189、3%為t091及t338。在MRSA當中來自急診及門診菌株54% 有攜帶pvl，來自病房的則為24%。MSSA當中來自急診及門診菌株則有17%攜帶pvl，未發現來自病房的菌株攜帶pvl。攜帶pvl的MRSA抗藥比例較低，但對於erythromycin及trimethoprim/sulfamethoxazole卻較高。我們實驗中皮膚軟組織感染的菌株大多為IEC type B，且大多數都有攜帶 hla及hld。在classical Staphylococcal enterotoxin genes中seb佔最多，而在其他SEs則為seh佔最多。發現有五株帶有tst，九株bbp 陽性菌株有四株為t091。目前只發現一株攜帶edin，未發現菌株攜帶lukM，大部分的菌株都有攜帶lukE-lukD。 此研究初步了解台大醫院皮膚及軟組織感染之S. aureus特性。結果大致和其他台灣的研究相符，但也有些許不同，其差異可能是地域上或是檢體來源的差異，但還須進一步的實驗探討。

Staphylococcus aureus is one of the human normal inhabitant resident microbiota. It is an important human pathogen responsible for many infectious diseases including skin and soft tissue infections (SSTIs), pneumonia, endocarditis and blood-stream infections. S. aureus will be classified as healthcare-associated or community-associated. Prevalence of methicillin-resistant S. aureus (MRSA) and its ability to resist multiple drugs has posed a serious challenge. S. aureus is one of the common infections from skin and soft tissue. Because most of the staphylococcal SSTIs has recurrence, patients do not have good immune response to the infection. Therefore, the aim of our study is to know the characterization of S. aureus isolated from skin and soft tissue infection. We collected 129 isolates from emergency and/or outpatient and 91 isolates from hospitalized patients. Among all isolates, 172 of them are from skin and soft tissue infection. MRSA from emergency and outpatient is more sensitive than hospitalized one, but no significant difference in MSSA. In the distribution of spa types, 3% of SSTI isolates are t091 and t338, 4% is t189, 8% is t008, 12% is t037 and 16% is t437. Among MRSA, 54% of isolates from emergency and outpatient and 24% of isolates from hospitalized patient is pvl- positive. Among MSSA, 17% of isolates from emergency and outpatient and none of isolates from hospitalized patient is pvl- positive. Despite of erythromycin and trimethoprim/sulfamethoxazole, pvl- positive MRSA is less resistant. Most of the SSTI isolates in our study are IEC type B. Most of the SSTI isolates in our study are hla- positive and hld- positive. The most frequent enterotoxin is seb in classical Staphylococcal enterotoxins and seh in other enterotoxins. Five SSTI isolates in our study are tst- positive. 4 of the 9 bbp- positive isolates are t091. We have found one isolate with edin no isolate with lukM and most of the isolates with lukE-lukD. In this study we examined the characterization of S. aureus isolate from skin and soft tissue infection preliminary. Most of the results in our study are similar with others although there is a little difference. The geographical differences and the sample origin may cause the divergence and need more experiment to explore.