耐亚胺培南鲍氏不动杆菌超广谱β-内酰胺酶与AmpC酶研究

Study on extended spectrum β-lactamase and AmpC enzyme in imipenem-resistant Acinetobacter baumannii

目的:研究临床分离的54株耐亚胺培南鲍氏不动杆菌耐药表型和基因型。方法:应用VITEK 2-compact全自动细菌鉴定仪进行细菌鉴定和药物敏感试验,采用改良三维试验方法同时检测AmpC酶和超广谱β-内酰胺酶,用PCR检测ampC和blaTEM基因,并进行基因测序。结果:54株耐亚胺培南鲍氏不动杆菌中,对抗菌药物耐药率除左氧氟沙星、美罗培南和头孢哌酮/舒巴坦外均>77%,对头孢哌酮/舒巴坦的耐药率最低(24.1%)。三维试验表明,36株(66.7%)单产AmpC酶,6株(11.1%)单产超广谱β-内酰胺酶,6株(11.1%)同时产AmpC酶和超广谱β-内酰胺酶。54株菌(100.0%)经PCR扩增和序列分析表明均同时携带ampC和blaTEM-1基因。结论:耐亚胺培南鲍氏不动杆菌多重耐药现象严重,同时携带ampC和blaTEM-1基因是本组鲍氏不动杆菌对β-内酰胺类药物耐药的主要原因。

Objective： To analyse the resistant genotype and phenotype of 54 strains imipenem-resistance Acinetobacter baumannii（IRABA） isolated from 54 patients.Methods： The strains of ABA were detected and antimicrobial susceptibility test were conducted by VITEK 2-compact system.ESBLs and AmpC enzyme were detected in 54 strains by improved three-dimensional test;AmpC and blaTEM genes were amplified by PCR,and genes of partial positive products were sequenced.Results： The rate of drug resistances in 54 strains of imipenem-resistant A.baumannii isolated from patients all exceeded 77 % except to levofloxacin,mempenem and cefoperazone/sulbactam.Three-dimensional test indicated that 36 strains（66.7 %） were only AmpC enzyme positive,6 strains（11.1 %） were only ESBLs positive,6 strains（11.1 %） were both ESBLs and AmpC enzyme positive.PCR and sequencing found 54 strains（100.0 %） produced ampC and blaTEM-1.Conclusion： The phenomenon of multi-drug resistance of Acinetobacter baumannii to antibiotic is severe.Carrying ampC and blaTEM-1 genes may be the main reason for the resistance to β-lactams.