铜绿假单胞菌超广谱β-内酰胺酶、AmpC酶的检测及耐药性分析

Extended-spectrum Beta-lactamases and AmpC Enzymes of Pseudomonas aeruginosa:Their Detection and Resistance Analysis

目的了解铜绿假单胞菌产超广谱β-内酰胺酶(ESBLs)和AmpC酶的情况及其耐药特征,为临床抗菌药物的合理使用提供实验室依据。方法采用VITEK-32系统鉴定细菌;K-B法测定细菌对抗菌药物的敏感性;双纸片协同试验法检测ESBLs;头孢西丁三维试验法检测AmpC酶。结果在105株铜绿假单胞菌中检出单产AmpC酶、单产ESBLs及同时产AmpC酶和ESBLs细菌分别为28株(26.7%)、20株(19.0%)、5株(4.8%),产AmpC酶菌的检出率明显高于产ESBLs菌,差异有统计学意义(P<0.05)。结论产ESBLs和AmpC酶是导致铜绿假单胞菌耐药的主要两种酶,产酶株对多种抗菌药物耐药,亚胺培南具有很高的抗菌活性。

OBJECTIVE To investigate the prevalence of strains producing extended-spectrum β-lactamases （ESBLs） and AmpC β-lactamases in Pseudomonas aeruginosa, and to supply the laboratory evidence for antibiotic rational application in clinic. METHODS Totally 105 clinical isolates of P. aeruginosa were identified with VITEK-32. Drug sensitivities were determined by Kirby-Bauer methods. ESBLs were detected by double-disc synergy test,and cefoxitin three dimensional test was applied to filter AmpC positive strains. RESULTS Among 105 strains of P. aeruginosa, 28 strains （26.7%） were AmpC enzymes positive, 20 strains （19.0%） were ESBLs positive, and 5 strains（4. 8%）were AmpC＋ ESBLs positive. The detective rate of producing AmpC β-lactamases strains was higher than that of producing ESBLs strains. There was significant difference between them. CONCLUSIONS ESBLs and AmpC β-lactamases are two main enzyme types conferring resistance to β-lactam antibiotics in clinical isolates of P. aeruginosa. Imipenem can be the first choice for treating infections caused by P. aeruginosa producing ESBLs or AmpC β-lactamases.