Send to

Choose Destination
Indian J Med Microbiol. 2008 Jul-Sep;26(3):233-7.

An evaluation of four different phenotypic techniques for detection of metallo-beta-lactamase producing Pseudomonas aeruginosa.

Author information

Department of Laboratory Medicine, All India Institute of Medical Sciences, New Delhi - 110 029, India.



The present study was undertaken to detect metallo-beta-lactamase (MBL) in nosocomial isolates of Pseudomonas aeruginosa by four different phenotypic methods.


Ninety-one consecutive P. aeruginosa isolates were subjected to susceptibility testing by disc-diffusion assay and Vitek 2. Imipenem resistance was determined by three different methods (disc-diffusion, Vitek 2 and E test). Screening for MBL production was done by imipenem-EDTA combined disc test, imipenem-EDTA double-disc synergy test, imipenem-EDTA MBL E test and EDTA disc potentiation using four cephalosporins.


Of 63 imipenem resistant isolates, MBL screening could be done in 56 isolates, of which 48 were MBL positive by combined disc test and 36 by the double disc synergy test. For confirmation of MBL production, MBL E test was done in 30 isolates. All the 30 isolates were confirmed to be MBL positive by the MBL E test method. EDTA disc potentiation using four cephalosporins was not very useful for MBL detection.


Imipenem-EDTA combined disc test and imipenem-EDTA MBL E test are equally effective for MBL detection, but given the cost-constraints, combined disc test can be used as a convenient screening method in the clinical microbiology laboratory.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Medknow Publications and Media Pvt Ltd
Loading ...
Support Center