某院CRAB同源性及其生物膜形成能力分析

目的分析某院耐碳青霉烯鲍曼不动杆菌(CRAB)的耐药特性、主要流行克隆型及生物膜形成能力,为更好地防控CRAB感染提供参考。方法收集该院32株非重复CRAB菌株,采用全自动微生物分析系统进行药敏检测,结晶紫染色法检测CRAB生物膜形成能力,脉冲场凝胶电泳(PFGE)分析CRAB克隆多态性。结果 32株CRAB对四环素的耐药率最低(68.6%),对其他药物的耐药率均78%。PFGE同源性结果显示,32株CRAB可分为9个(A～I型)不同克隆型,每个克隆型包括1～9株,主要的流行克隆型是A型(9株)和E型(7株)。32株CRAB中,14株(43.8%)有生物膜形成能力且均为弱阳性;各克隆型间生物膜形成能力比较,差异无统计学意义(χ~2=6.636,P=0.659)。随着生物膜形成能力的增强,耐药率均有不同程度地升高,但产膜菌与非产膜菌两组间仅庆大霉素耐药率比较,差异具有统计学意义(χ~2=4.879,P0.05)。结论该院CRAB存在以A型和E型为主的不同克隆型传播,生物膜形成能力的增强能提高菌株的耐药性。

Homology and biofilm-forming ability of carbapenem-resistant Acinetobacter baumannii in a hospital

Objective To analyze the resistance characteristics, main epidemic clones and biofilm formation ability of carbapenem-resistant Acinetobacter baumannii (CRAB) in a hospital, and provide reference for better prevention and control of CRAB infection. Methods 32 non-repetitive CRAB strains were collected from the hospital, antimicrobial susceptibility was detected by automatic microbiological analysis system, biofilm formation ability was detected by crystal violet staining, polymorphism of CRAB clones was analyzed by pulsed-field gel electrophoresis (PFGE). Results Resistance rate of 32 CRAB strains to tetracycline was the lowest (68.6%) and to other antimicrobial agents were all>78%. PFGE homology results showed that 32 CRAB strains could be divided into 9 different clone types (type A-I), each clone type consisted of 1-9 strains, the main prevalent clones were type A (n=9) and type E (n=7). Of 32 CRAB strains, 14 (43.8%) had biofilm formation ability and were weakly positive; there was no significant difference in biofilm formation ability among different clones (χ²=6.636, P=0.659). With the enhancement in biofilm formation ability, antimicrobial resistance rate increased in varying degree, but only gentamicin resistance rate between biofilm formation strains and biofilm non-formation strains was significantly different(χ²=4.879, P<0.05). Conclusion There are different clonal transmission of CRAB in this hospital, mainly type A and E, enhancement in biofilm formation ability can increase the drug resistance of strains.