Establishment and evaluation of the new typing systems for the epidemiological investigation in MRSA (Methicillin Resistant Staphylococcus Aureus) infections

MRSA（耐甲氧西林金黄色葡萄球菌）感染流行病学调查新分型系统的建立和评价

基本信息

批准号：
02671034
负责人：
MATSUMOTO Hideki
金额：
$ 1.28万
依托单位：
School of Medicine, Shinshu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

This study has been carried out to know the most useful way to " type " the MRSA strains for the epidemiological servey in the infections caused by the bacterium. Six typing systems of S. aureus have been evaluated for their utility for the each 96 MRSA and 12 MSSA (Methicillin Se-nstitive S. aureus) strains of known origins. Analysis by Pulsed Field Gel Electrophoresis (PFGE) for the genomic DNA cut with a restriction enzyme, SmaI, enabled us to classify the strains into 14 types based on the DNA bands separated by the electrophoresis. Ninty-eight per cent strains were revealed to have a plsmid or plasmids and molecular size of the DNA ranged from about lkb to 40kb. A very interesting finding was that 87% of the MRSA have, in common, a plsmid of 24, 3 kb. This plasmid was rarely detected in MSSA. Results of the biochemical tests, i. e., fermentation of lactose and sucrose, could classify the strains into the four biotypes which seemed to be of limited epidemiological value. In the phage typing, only 10% strains of MRSA were sensitive to one or more typing phage (s) diluted to IRTD. By contrast, 73% strains of MSSA were typable. Typing by coagulase (cell free) neutralization test (antisera from type I to type VIII inclusive were employed) gave a disappointing results for the purpose of epidemiological investigation, as the 98% strains belonged to a same type, type ii. All of the results summarized above led us to conclude as follows ; In the epidemiological investigation of the infections due to MRSA, at least when we are going to clarify the spread of contamination, the most useful way to " type " an isolate is combination of the results presented by analysis, by PFGE, for genomic DNA digested with SmaI, analysis of plasmic DNA, especially those which is larger than 20kb and biotyping based on their ability to ferment lactose and sucrose.

本研究的目的是了解对 MRSA 菌株进行“分型”的最有用方法，以用于该细菌引起的感染的流行病学服务。已评估了金黄色葡萄球菌的六种分型系统对已知来源的 96 种 MRSA 和 12 种 MSSA（甲氧西林不敏感金黄色葡萄球菌）菌株的效用。通过脉冲场凝胶电泳 (PFGE) 对限制性内切酶 SmaI 切割的基因组 DNA 进行分析，使我们能够根据电泳分离的 DNA 带将菌株分为 14 种类型。 98%的菌株被发现具有一个或多个质粒，并且DNA的分子大小范围为约1kb至40kb。一个非常有趣的发现是，87% 的 MRSA 都具有 24, 3 kb 的共同质粒。该质粒在 MSSA 中很少检测到。生化测试的结果，i。例如，乳糖和蔗糖的发酵，可以将菌株分为四种生物型，这似乎具有有限的流行病学价值。在噬菌体分型中，只有 10% 的 MRSA 菌株对稀释至 IRTD 的一种或多种分型噬菌体敏感。相比之下，73% 的 MSSA 菌株是可分型的。对于流行病学调查的目的，通过凝固酶（无细胞）中和试验（使用I型至VIII型抗血清）进行分型的结果令人失望，因为98％的菌株属于同一类型，即ii型。上面总结的所有结果使我们得出如下结论：在 MRSA 感染的流行病学调查中，至少当我们要澄清污染的传播时，“分型”分离株的最有用方法是结合 PFGE 分析基因组 DNA 消化得到的结果使用 SmaI，分析血浆 DNA，尤其是大于 20kb 的 DNA，并根据其发酵乳糖和蔗糖的能力进行生物分型。