目的从基因组型和表型两方面解析从医院环境中分离出的社区型甲氧西林耐药性金黄色葡萄球菌(MRSA),对携带杀白细胞素(PVL)基因的MRSA中的PVL溶原噬菌体进行分型。方法聚合酶链式反应(PCR)解析菌株所携带的SCCmec基因岛型及PVL毒素基因;凝固酶试验测定菌株的凝固酶型;设计8组PCR反应组合检测PVL溶原噬菌体型。结果36株菌株所携带的SCCmec基因岛分型多样化。携带Ⅳc型SCCmec的菌株占多数,为16株(44.4%),其次为携带Ⅱ型SCCmec的菌株,为10株(27.8%)。各菌株所携带的SCCmec型别与菌株的凝固酶分型高度一致。经多重PCR检测,6株P忱阳性菌株所携带的PVL噬菌体型分别为φ108PVL型(3株),φ2958PVL型(1株)和φSa2mw型(2株)。结论院内分离的社区型MRSA的基因型和表型多样化,PVL噬菌体分型的多重PCR系统具有可应用性,应用此系统对鉴别具有异构六角形头部和伸长形头部的PVL溶原噬菌体有意义。
Objective To analyze the genotype and phenotype for community acquired MRSA,which were isolated from hospital environment and to type the PVL lysogenic phage linearized in chromosomal DNA of PVL positive MRSA strains. Methods Polymerase chain reaction (PCR) was used for typing SCCmec element carried by MRSA. Coagulase test was conducted to determine the coagulase isotype. Existence of PVL toxin gene was assayed for all strains by individual PCR. Eight sets of PCRs were used for typing the PVL lysogenic phage hnearized in chromosomes of MRSA strains. Results Diversity of SCCmec elements was found among those MRSA strains. A high percentage of MRSA strains (44.4%) carried Ⅳc SCCmec element,followed by MRSA strains carrying Ⅱ SCCmec element (10 of 36,27.8%). The SCCmec type of each strain was highly consistent with its coagulase type. The PVL phage types of six PVL positive MRSA strains were φ108PVL (3 strains), φ2958PVL ( 1 strain) and φSa2mw (2 strains),respectively. Conclusion MRSA strains showed phenotypic and genotypic diversity in SCCmec types and coagulase isotypes. Multiplex PCR for PVL lysogenic phage typing was apphcable. PVL phage could be classified into two groups, namely, the icosahedral-head type and the elongated-head type.