40株多重耐药鲍氏不动杆菌同源性和噬菌体裂解谱分析

Rapid identification of 40 strains of multidrug-resistant Acinetobacter baumannii clones by pulsed-field gel electrophoresis and investigation of their susceptibility to lytic bacteriophages

目的分析多重耐药鲍氏不动杆菌（MDRAB）同源性和噬菌体的裂解谱。方法从解放军三〇七医院2012年住院患者临床标本中分离MDRAB，K—B法检测细菌耐药性，脉冲场凝胶电泳（PFGE）分析其同源性，采用医院污水富集法分离噬菌体，平皿斑点法观察裂解谱。结果40株MDRAB对18种常用抗生素呈现高度耐药，亚胺培南的耐药率达87．5％，对头孢哌酮／舒巴坦的耐药率为75．0％。PFGE分型显示40株MDRAB分A、B、C3个克隆型，其中A型4株，B型26株，C型4株，另有6株相对独立菌株。成功分离出16株MDRAB裂解性噬菌体，用来自不同克隆群的3种噬菌体制成鸡尾酒可裂解30株（75．0％）MDRAB。结论PFGE分析发现MDRAB存在克隆传播，噬菌体能有效裂解MDRAB，在MDRAB感染防控中的作用值得进一步研究。

Objective To determine the genetic diversity of multidrug-resistant Acinetobacter baumannii （MDRAB） strains and to test their susceptibility to bacteriophages. Methods Acinetobacter baumannii was isolated from hospitalized patients from January 2012 to December 2012. Bacterial resistance to antibiotic was tested by Kirb-Bauer method. Genotyped was detected by pulsed-field gel electrophoresis. Bacteriophages were isolated from raw sewage using these Acinetobacter baumannii strain as host cells,lysis spectrum was determined by phage plaque. Results 40 Acinetobacter baumannii were resistant to multiple antibiotics including carbapenems and β-lactamase inhibitors. The genotypes were distributed into three clones containing 4, 26, and 4 isolates respectively. Other six isolates were singletons. 16 strains of Acinetobacter bacteriophages with different lysis spectrum were isolated. The cocktail, which was made of three newly isolated Acinetobacter bacteriophages,was found to lyse 30 of the 40 analyzed strains and distributed into the different clonal complexes. Conclusions This pilot study suggests that systematic genotyping of MDRAB strains can improve our epidemiological understanding of transmission in the hospital. Phage can effectively destroy MDRAB and deserve further research.