铜绿假单胞菌对β-内酰胺酶类抗生素耐药机理的研究

Study on The Mechanism of Drug-resistanceAssociated with β-lactamase Antibiotics in Pseudomonas Aeruginosa

目的:检测铜绿假单胞菌对β-内酰胺酶类抗生素的耐药性,为临床合理应用抗生素提供参考依据。方法:采用K-B扩散法测定亚胺培南等7种抗菌药物对46株铜绿假单胞菌的体外抗菌活性,采用冻融法粗提铜绿假单胞菌酶液,用改良三维试验分析β-内酰胺酶类型。结果:46株铜绿假单胞菌均对3种以上抗生素耐药,表现为多重耐药。三维试验阳性率52.2%(24/46),其中单一产AmpC酶菌株15株,单一产ESBLs菌株6株,同时产AmpC酶及ESBLs菌株2株,1株产其它β-内酰胺酶。结论:产生β-内酰胺酶是铜绿假单胞菌对β-内酰胺酶类抗生素耐药的主要机制之一,其中β-内酰胺酶以产AmpC酶为主,是造成临床上铜绿假单胞菌对头孢菌素第3、4代耐药的主要原因。

Objective： To investigate the mechanism of drug-resistance associated with β-lactamase in Pseudomonas aeruginosa and provide evidence of using antibiotic rationally.Methods： 46 strains of Pseudomonas aeruginosa were isolated from patients.K-B disk diffusion method was used in susceptibility testing.A modified three-dimensional test was used to detected the type of the β-lactamase.Results： In 46 strains of Pseudomonas aeruginosa,the total positive rate of β-lactamase was 52.2%（24/46）,the positive rate of ESBLs and AmpCβ-lactamase were 13.0%（6/46） and 32.6%（15/46） respectively.Both AmpC and ESBLs positive is 4.3%（2/46）,other β-lactamase positive is 2.2%（1/46）.Conclusion：The production of β-lactamase is the major mechanism of the drug-resistance associated withβlactamase antibiotics in Pseudomonas aeruginosa.The production of AmpC enzymes was the main cause for the resistance to the third and fourth generation cephalosporin in Pseudomonas aeruginosa.