呼吸科住院患者耐碳青霉烯鲍曼不动杆菌抗菌药物敏感性及其分子特征

目的调查深圳市人民医院呼吸科住院患者耐碳青霉烯鲍曼不动杆菌（CRAB）的抗菌药物敏感性和耐药分子机制，以及克隆流行情况。方法收集2010年深圳市人民医院呼吸科住院患者临床分离CRAB29株，琼脂稀释法测定亚胺培南等15种抗菌药对CRAB的最低抑菌浓度（MIC），PCR和DNA测序分析CRAB碳青霉烯酶基因型，脉冲场凝胶电泳（PFGE）分析菌株同源性。结果多粘菌素B对29株CRAB抗菌活性最强，敏感性100％，MIC50／MIC90为1／1μg/mL，其次米诺环素，敏感性96．6％，MIC50／MIC90为4／4μg/mL，替加环素中介率高达96．6％，MIC50／MIC90为4／4μg/mL。96．6％（28／29）CRAB携带ISAba1—blaOXA-23-like,对亚胺培南和美罗培南高度耐药，亚胺培南和美罗培南的MIC集中分布在32—64μg／mL；1株携带ISAba1—blaOXA-51-like CRAB，对亚胺培南和美罗培南中度耐药，亚胺培南和美罗培南的MIC分别为4μg/mL和8μg/mL。29株CRAB未发现blaOXA-24-like、blaOXA-143-like、金属酶基因及KPC酶基因。29株CRAB经PFGE分型共分2型，以A型28株（96．6％）为主要流行克隆，均携带ISAba1-blaOXA-23-like。结论2010年我院呼吸科临床分离CRAB主要携带ISAba1—blaOXA-23-like基因，并以克隆播散流行。

Susceptibility and molecular mechanism of carbapenem-resistant Acinetobacter baumannii isolated from respiratory department inpatients in a hospital

Objective To investigate the susceptibility, carbapenemase genotypes and clonal relatedness of carbapen- era-resistant Acinetobacter baumannii （ CRAB ） isolated from the respiratory department inpatients in Shenzhen Peo- ple＇ s Hospital. Methods Twenty-nine non-duplicated CRAB isolates were coUected from the respiratory department inpatients in this hospital in 2010. The minimum inhibitory concentrations （MICs） of CRAB against fifteen antimi- crobial agents were detected by agar dilution method. PCR and DNA sequencing were used to investigate the carbap- enemase genotypes of CRAB. All isolates were typed by pulse field gel electrophoresis. Results Polymixin B showed the highest activity against twenty-nine CRAB isolates （susceptibility of 100% ）, with the MIC50/MIC90 of 1/1 μg/mL, followed by minocycline （susceptibility of 96.6% ）, with the MIC50/MIC90 of 4/4 μg/mL, and tige- cycline （ intermediate of 96.6% ） , with the MIC50/MIC90 f 4/4 μg/mL, respectively. ISAba1-blaOXA-23-like was the most prevalent carbapenemase gene detected in 96.6% （28/29） of CRAB isolates which showed high resistance to imipenem and meropenem, with the main distribution of MICs ranging between 16 to 64 μg/mL. One CRAB isolateharboring ISAba1-blaOXA-51-like, exhibited intermediate resistance to imipenem and meropenem, with the MIC of 4μg/mL and 8μg/mL, respectively, blaOXA-24-1ike, blaOXA-24-like, Metallo-（ -lactamase and KPC genes were not de- tected in any of the CRAB isolates. Two distinct PFGE patterns were observed among the twenty-nine isolates. All of type A isolates harbored ISAba1-blaOXA-23-like, accounting for 96.6% （28/29）. Conclusion The prevalence of CRAB clone harboring ISAba1-blaOXA-23-like occurred in respiratory department in our hospital during 2010.