Study On Detection Methods And Drug Resistance Of Metallo Beta-lactamases Of Bacteria

Objective To explore and establish a method for screening of the metallo - β - lactamase in the clinical microbiology laboratory and investigate the drug resistance of MBL—producing bacteria to instruct reasonable clinical chose of antibiotics. Methods we collected 58 strains of imipenem-resistant gram-negative bacilli identified by WalkAway-40. Firstly,imipenem-resistant or ceftazidime-resistant strains were selected by using K-B method . Then, using EDTA,CuCl₂, FeCl₂ ,2-MPA, and MPA as enzyme inhibitor, using ceftazidime and imipenem as the substrate to detect the metallo- β - lactamase by double-disk synergy test in the M-Hayar. The MBL production of imipenem-resistant strains were also detected by the imipenem-EDTA disk method .The microbiology sensitivity tests of MBL-positive isolates were assessed by K-B method. Results 1. 42 strains imipenem-resistant bacteria were detected in 58 strains of clinical isolated gram-negative bacilli,and 27 strains ceftazidime- resistant bacteria were also detected.There were 24 strains resistant to ceftazidime and imipenem,and 13 strains sensitive to all the substrats.Three strains showed sensitivity to imipenem but resistance to ceftazidime,and 18 strains showed resistance to imipenem but sensitivity to ceftazidime.2. 17(40.5%) strains of metallo-b-lactamases-producing bacteria, including 9 strains of X. Maltophilia, 2(9.1%) strains of P.aerugnosa, 3 strains of Flavobacterium meningo,2 strains of C.gleum,1 strains of Pseudomonas alcaligenes were detected in 42 strains of...