铜绿假单胞菌的耐药性分析与金属β-内酰胺酶检测

Antimicrobial Resistance of Pseudomonas aeruginosa and Detection of Its Metallo-β-lactamases

目的了解住院患者送检标本中分离出的铜绿假单胞菌的耐药特点及其产金属β-内酰胺酶（MBLs）情况。方法收集2005年7月-2008年8月住院患者送检的临床标本中,共分离出的铜绿假单胞菌95株,采用德灵公司生产的NC21鉴定药敏板及配套试剂和VITEK-32进行鉴定和测定药物敏感性,并对耐亚胺培南的30株菌用K-B法确认亚胺培南的敏感性和检测美罗培南、头孢哌酮/舒巴坦和多黏菌素E的敏感性,其中19株经K-B法确认为亚胺培南耐药的菌株用Etest法检测MBLs。结果95株铜绿假单胞菌的耐药率结果显示,以阿米卡星的耐药率最低,为15.4%,对其他抗菌药物的耐药率为26.7%-100.0%;经仪器检测耐亚胺培南的30株菌中,对美罗培南和亚胺培南的敏感性差异无统计学意义（u值1.04,P〉0.05）,头孢哌酮/舒巴坦的敏感性高于亚胺培南（u值2.6,P〈0.05）,多黏菌素E的敏感性高于亚胺培南（u值527.5,P〈0.05）;Etest从19株（经K-B法确认为亚胺培南耐药的菌株）菌中检出12株产金属β-内酰胺酶,亚胺培南耐药株金属β-内酰胺酶检出率为63.2%。结论临床标本中分离出铜绿假单胞的多药耐药现象十分严重,亚胺培南耐药株产MBLs比例较高;多黏菌素E、头孢哌酮/舒巴坦对耐亚胺培南铜绿假单胞菌治疗可能有效,产MBLs铜绿假单胞菌有院内间歇流行趋势。

OBJECTIVE To investigate antimicrobial resistance of Pseudomonas aeruginosa and detect metallo-β-lactamases（MBLs）in clinic.METHODS Ninety-five strains of P.aeruginosa were isolated from sputum samples during the period from Jul 2005 to Aug 2008 in the affiliated hospital of North Sichuan Medical College.Bacteria identification and antimicrobial susceptibility test（to 18 antibiotics）were performed by VITEK-32 system and NC21,The K-B method was applied to affirm the susceptibility to imipenem,meropenem,cefoperazone/sulbactam and polymyxin E of the 30 strains with antimicrobial resistance to imipenem confirmed by instrument.The Etest method was utilized to detect the MBLs of 19 strains with antimicrobial resistance to imipenem confirmed by the K-B method.RESULTS The antimicrobial resistance rates of the 95 strains display that the lowest rate was amikacin which was 15.4%,the other antbiotic′s resistance rates fluctuateed from 26.7% to 100.0%;in the 30 strains with antimicrobial resistance to imipenem confirmed by instrument,there was no remarkable difference between the imipenem and meropenem（u 1.04,P0.05）,the susceptibility of cefoperazone/sulbactam was higher than the imipenem（u 2.6,P0.05）,the susceptibility of polymyxin was also higher than the imipenem（u 527.5,P0.05）.Twelve strins generating MBLs were screened from 19 strins with imipenem resistance confirmed by K-B,and the positive rate was 63.2%.CONCLUSIONS The multidrug resistance of P.aeruginosa which isolated from our clinical specimens is a serious issue.The producing rate MBLs within the imipenem resistance strains is higher;there should be effiective if using the polymyxin B or cefoperazone/sulbactam to treat the imipenem resistance P.aeruginosa.MBLs producing P.aeruginosa has a trend to prevail intermittently in the hospital.