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目的分析临床血培养报阳的凝固酶阴性葡萄球菌(CNS)生物被膜形成能力及耐药性特征。方法收集某院临床血培养报阳的CNS 126株,采用96孔聚苯乙烯培养板分析生物被膜形成能力,聚合酶链反应(PCR)法检测细菌耐药基因mecA,并分析菌株的耐药情况。结果 126株CNS中,87株(占69.04%)生物被膜阳性,105株(83.33%)携带mecA基因。CNS对青霉素、苯唑西林及红霉素的耐药率均>80%,未发现对利奈唑胺、奎奴普丁/达福普汀、万古霉素和替加环素耐药的菌株;耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)对环丙沙星、庆大霉素、左氧氟沙星、青霉素、利福平和复方磺胺甲口恶唑的耐药率均高于甲氧西林敏感凝固酶阴性葡萄球(MSCNS)(均P<0.05)。对苯唑西林敏感的CNS中,有2株mecA检测阳性。结论临床血液来源的CNS具有较高的生物被膜形成能力,绝大部分为MRCNS,且表现为多重耐药;存在耐药表型与基因型不一致的菌株。
Objective To analyze the biofilm formation ability and drug resistance of coagulase-negative staphylococci (CNS) in clinical blood culture. Methods A total of 126 CNS positive clones were collected from a hospital blood culture biofilm formation assay using 96-well polystyrene plates. The drug resistance gene mecA was detected by polymerase chain reaction (PCR) and the drug resistance of the strains was analyzed . Results Of 126 CNS strains, 87 (69.04%) biofilms were positive and 105 (83.33%) carried mecA gene. The drug resistance rates of CNS to penicillin, oxacillin and erythromycin were both> 80%. No strains resistant to linezolid, quinupristin / dalfistin, vancomycin and tigecycline were found. The resistance rates of MRCNS to ciprofloxacin, gentamycin, levofloxacin, penicillin, rifampicin and sulfamethoxazole were all higher than that of methicillin-sensitive coagulase-negative Stratum granulosus (MSCNS) (all P <0.05). Among the CNS susceptible to oxacillin, two were positive for mecA. Conclusion The clinical blood derived CNS has a high ability of biofilm formation, most of which is MRCNS, and is characterized by multiple drug resistance. There is a strain with inconsistent drug resistance phenotypes and genotypes.