铜绿假单胞菌耐药与高活性β内酰胺酶

Relationship between antimicrobial susceptibility and highly active β-lactamases in Pseudomonas aeruginosa

目的了解铜绿假单胞菌临床分离株的耐药性及其AmpC酶、超广谱β内酰胺酶(ESBLs)和金属β内酰胺酶(MBLs)的产生情况,指导临床合理选用抗生素。方法采用K-B纸片扩散法检测药物敏感性,通过改良酶提取物头孢西丁和头孢曲松三维试验检测AmpC酶和ESBLs,E试验MBL试条检测MBLs。结果186株临床分离铜绿假单胞菌对亚胺培南的敏感率最高,达82.3%,对环丙沙星、哌拉西林/他唑巴坦、头孢他啶、阿米卡星、头孢哌酮/舒巴坦的敏感率依次为75.3%,74.2%,72.6%,71.0%,70.4%,对替卡西林、头孢哌酮、氨曲南的敏感率均<60%,对头孢噻肟和头孢曲松的耐药率分别为61.8%和55.9%。单产AmpC酶、同时产AmpC酶和ESBLs、单产ESBLs和单产MBLs检出率分别为8.6%(16/186),2.7%(5/186),14.5%(27/186),4.8%(9/186)。结论临床分离铜绿假单胞菌的耐药现象不容忽视,产生高活性β内酰胺酶是导致其耐药的机制之一,亚胺培南仍是治疗铜绿假单胞菌感染最有效的药物。

Objective To investigate the antimicrobial resistance and the prevanlence of production of AmpC β-lactamases, extended-spectrum β- lactamases（ESBLs） and metaUo β-lactamases（MBLs） in Pseudomonas aeruginosa （P.aeruginosa） clinical isolates, for guiding the rational use of antibiotics. Methods Antimicrobial susceptibility tests were done by Kirby-Bauer disk diffusions method, the phenotypes of P.aeruginosa strains harboring AmpC β-lactamases and/or ESBLs were detected by modified three-dimensional extract test, while MBLs were identified using MBL E-test strips. Results The susceptibility rate of 186 P. aeruginosa clinical isolates to imipenem was the highest about 82.3 %, as to ciprofloxacin, piperacillin/ tazobactam, ceftazidime, amikacin, cefoperazone/sulbactam were 75.3 %, 74.2 %, 72.6 %, 71.0 %, 70.4 % respectively, but to ticarcillin, cefoperazone, aztreonam were no more than 60 %, The resistant rates to cefotaxime and ceftriaxone were 61.8 % and 55.9 % respectively. AmpC β-lactamases, Amcp β-lactamases combined with ESBLs, ESBLs and MBLs producing strains were detected in 8.6 %, 2.7 %, 14.5 % and 4.8 % of P. aeruginosa respectively. Conclusion The resistant phenomenon of P. aeruginosa clinical isolates should not be ignored, production of highly active β-lactamases is one of resistant mechanisms in P. aeruginosa, imipenem is still the best choice for treating infection caused by P. aeruginosa.