多耐鲍曼不动杆菌分子流行病学分析

目的 分析云南省第三人民医院鲍曼不动杆菌分离株耐药表型及耐药基因分子流行病学特征. 方法 2013年6-9月,分离该院不同重症监护室(ICU)院内感染患者鲍曼不动杆菌28株,全自动微生物分析仪分类鉴定及耐药分析.PCR扩增及测序-内酰胺酶、氟喹诺酮类及氨基糖苷类等抗性基因及IS插入元件及整合子等. 结果 78.6%菌株为多药耐药菌,14.3%菌株为广泛耐药菌,7.1%的菌株为泛耐药菌. 100%菌株不仅对一代/二代头孢类抗生素耐药,且对三代/四代抗生素CRO、CAZ、 FEP及单环-内酰胺类(ATM)、氟喹诺酮类(CIP、LEV)、氨基糖苷类(AN)及磺胺类(FD)耐药.特别是92.9%菌株对碳青霉烯类抗生素耐药.质粒介导的D类-内酰胺类抗性基因blaOXA、氟喹诺酮类aac(6')-Ib-cr、qnrA及qnrD]及氨基糖苷类(aacA4、 aadA1及 aacC2)为主要基因型.100%菌株复合携带blaOXA、aac(6')-Ib-cr及aacA4等抗性基因及整合酶int1基因.85.7%菌株携带ISCR1.全部菌株为同一脉冲场凝胶电泳(PFGE)克隆群,且多位点序列分型(MLST)优势基因型为ST2. 结论 云南昆明第三人民医院ICU病房可能存在ST2多耐产碳青霉烯酶A. baumanni院内感染流行,有必要进行进一步流行病学及临床深入调查.防控措施及合理使用抗生素是当地医院当务之急.

Molecular characterization of multi-drug-resistant Acinetobacter baumannii isolated from patients in a hospital in Yunnan

Objective To analyze phenotypes and genotypes of Acinetobacter baumannii isolated from ICU patients in a hospital in Kunming, Yunnan province. Methods A total of 28 A. baumannii strains were isolated from the patients in this hospital, and the strains were identified and their susceptibilities to 21 antibiotics were tested by using the bioMe'rieux VITEK-2 system. PCR screening and sequencing was performed to identify -lactamase genes, fluoroquinolone resistance related genes, aminoglycoside resistance related genes and gene capturing elements. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were conducted to analyze the genetic relationships among the isolates. Results Among the strains isolated, 78.6% were MDR, 14.3% were XDR and 7.1% were PDR. All the isolates were resistant not only to 1st and 2nd generation cephalosporins and most 3rd and 4th generation cephalosporins (ceftriaxone, ceftazidime and cefepime), but also to monobactams (aztreonam), quinolones (ciprofloxacin and levofloxacin), aminoglycosides (kanamycin) and nitrofurantoin (furadantin). All the isolates co-carried blaOXA genes, quinolone resistance related gene-aac(6')-Ib-cr, aminoglycosides resistance related gene-aacA4 and gene capturing element-int 1. Phylogenetic analyses by PFGE revealed that all the isolates were in one clad. Conclusion MDR A. baumannii possessing blaOXA, aac(6')-Ib-cr, and aacA4 might circulate in this hospital, it is necessary to conduct further clinical and epidemiological survey, take effective control measures and use antibiotics rationally.