鲍曼不动杆菌对碳青霉烯类抗生素的耐药分析及基因型研究

Analysis of Carbapenem Resistant Acinetobacter baumannii

目的分析20株鲍曼不动杆菌对耐碳青霉烯类抗生素的耐药性及对碳青霉烯酶基因的研究。方法用API鉴定条进行细菌鉴定及K-B法进行药敏试验,用碳青霉烯酶4种基因的特异性引物进行聚合酶链反应(PCR)扩增和基因型的测序分析,并通过网上Genbank进行比对以确定编码酶基因的类型。结果 20株鲍曼不动杆菌对左旋氧氟沙星、丁胺卡那霉素、多粘菌素B的耐药率分别为50%、25%、4%。其它抗生素的耐药率均在90%以上。携带D类碳青霉烯酶OXA-23基因有17株(85%),携带OXA-51基因有15株(75%),OXA-24、OXA-58基因引物PCR扩增为阴性,随机各抽取3株OXA-23基因阳性株进行测序后通过在网上Genbank比对发现与OXA-23标准株99%同源,OXA-51基因阳性株与OXA-51标准株98%同源。结论本院耐碳青霉烯类抗生素的鲍曼不动杆菌对多粘菌素B的耐药率最低,其次是丁胺卡那霉素,以携带OXA-23型碳青霉烯酶基因为主,应引起临床高度重视,防止在院内广泛传播。

Objective To analyze the antibiotic carbapenem resistant Acinetobacter baumannii in this hospital.Methods API Identification system and the KB method were used for the identification and susceptibility test of the bacterial isolates.Specific primers for carbapenemases were used for polymerase chain reaction （PCR） sequencing,amplification and genotyping analysis.Results were compared with the data from GenBank.Results 20 Acinetobacter baumannii isolates were studied.The percentage of drug resistance to levofloxacin,amikacin and polymyxin B was 50%,25% and 4%,respectively.The degree of drug resistance to other antibiotics was over 90%.17 bacterial isolates （85%） carried Class D carbapenemases OXA-23 gene and 15 （75%） isolates carried OXA-51 gene.OXA-24 and OXA-58 gene were not detected.Three OXA-23 gene-positive strains were randomly selected and sequenced.These isolates were found to be homologous （99% ） with the standard OXA-23 strain.The isolated OXA-51 genepositive strains were found to have 98% homology with the OXA-51 standard strain.Conclusion The degree of drug resistance of Acinetobacter baumannii to polymyxin was low.Most of the isolates carried OXA-23-type carbapenemase gene.Special attention should be paid to prevent the spread of bacteria carrying the OXA-23 gene.