产超广谱β-内酰胺酶铜绿假单胞菌及其耐药性研究

Extended-spectrum β-Lactamases and Drug Resistance Against Pseudomonas aeruginosa

目的了解铜绿假单胞菌产超广谱β-内酰胺酶状况及对常见抗菌药物的体外抗菌活性。方法常规培养分离细菌,应用VITEK-2全自动细菌分析仪鉴定细菌,最低抑菌浓度(MIC)检测应用琼脂平板倍比稀释法,按CLSI规定的标准进行;应用PCR方法检测超广谱β-内酰胺酶基因;用SPSS软件分析结果。结果从临床各种感染标本中分离获得77株铜绿假单胞菌,对哌拉西林/他唑巴坦、头孢哌酮/舒巴坦、亚胺培南、美罗培南和帕珠沙星的MIC90分别为256、128、32、16μg/ml;PCR检测77株铜绿假单胞菌,共有21株产酶,产酶率为27.3%;产酶菌株和非产菌酶株对8种抗菌药物的耐药性差异无统计学意义(P>0.05)。结论医院分离的铜绿假单胞菌耐药非常严重,但产ESBLs酶并不是其主要的耐药机制,临床微生物实验室应加强对该菌的耐药表型检测,有助于临床合理选择应用抗菌药物。

OBJECTIVE To understand the extended-spectrum β-lactamases（ESBLs） and in vitro antibacterial activity of commonly used antimicrobial agents against Pseudomonas aeruginosa.METHODS All strains were isolated and identified by routine procedure and VITEK-2 automatic bacterial identification instrument.Minimum inhibitory concentration（MIC） detection used agar plate dilution method following the standand of CLSI.PCR was used to amplify the ESBLs genes.Data were analyzed by SPSS.RESULTS Seventy-seven strains of P.aeruginosa were isolated from clinical infectious specimen.The MIC90 of piperacillin/tazobactam was up to 256 μg/ml and cefoperazone/sulbactam and imipenem were 128μg/ml and 32μg/ml,respectively.MIC90 of meropenem and pazufloxacin were both up to 16μg/ml.Among 77 P.aeruginosa strains,21 strains were positive of ESBLs gene with PCR detection,the ratio was 27.3%.But there were not significant differences in MIC of all antibacterial agents between the producing ESBLs strains or not.CONCLUSION The drug resistance of P.aeruginosa isolated from our hospital is very serious.But ESBLs are not the major mechanism of drug resistance.Clinical micrabiological laboratory should strengthen the drug resistant phenotype detection against P.aeruginosa in order to select clinical antimicrobial agents rationally.