耐甲氧西林金黄色葡萄球菌的两种新SCCmec型别及其抗药性研究

为探明本地区耐甲氧西林金黄色葡萄球菌(Staphylococcusaureus)的耐药性、流行病学分布状况及携带的葡萄球菌染色体mec盒(SCCmec)型别,用K-B琼脂扩散法、E-test和多位点PCR,对临床分离的金黄色葡萄球菌菌株进行了SCCmec分型及耐药性测定。结果发现了两种新的SCCmec型别,新1型含Ⅱ型的mecA上游特异性位点B和位于mecA内的M位点以及Ⅲ型的下游位点F,缺乏Ⅱ型上游位点C和下游位点D、G;新2型含Ⅰ、Ⅱ型的上游特异性位点A、B和两个Ⅲ型的下游位点F、H,同样缺乏位点C、D、G,可能分别为原有Ⅱ型和Ⅰ、Ⅱ型与Ⅲ型的基因重组株;且携带有新SCCmec型别的MRSA菌株,其流行病学分布特点及抗药性也与国外已报导的菌株不同,多分自门诊病人,且耐药性高,抗药谱广,值得引起高度重视和关注。

Two kinds of new SCCmec type in Methicillin-resistant Staphylococcus aureus and their susceptibility to the antibiotics

In order to explore the resistance, epidemical distribution and the staphylococcal chromosome cassette mec (SCCmec) types of Methicillin-resistant S. aureus (MRSA) in the area of Haikou, the resistance and SCCmec type of MRSA isolated from clinical sample has been tested using the K-B Agar diffuse, E-test and multiplex PCR strategy, resulting that two kinds of new SCC mec types were found in them. Type-newl possess three loci of B, M, F. Locus M, which locate in mecA, is the indicator of mecA, and also used as the positive control. Locus B, which locate in upstream of mec A, is specific for type- II and F, which locate in downstream of mec A, is specific for type- iU ; and so, type-newl was combined from the type- II and - I . Type-new2 possess five loci of A, B, M, F, H. Locus A, which is locate in upstream of mecA, is specific for type- I and H, which is locate in downstream of mecA, is also specific for type- 1 ; and so, type-new2 was combined from the type- I , - II and - I . The strains carrying new SCC mec types are different from that carrying old SCC mec types in the epidemical distribution and resistance to the antibiotics. They can be usually isolated from the out-patients and have high level and wider range of resistance to antibiotics. It must be paid more attention to them.