Study of metallo-beta-lactamase production in clinical isolates of Pseudomonas aeruginosa.

A study of metallo-beta-lactamase (MBL) production was done in clinical isolates of Pseudomonas aeruginosa. Isolates resistant to ceftazidime and imipenem were screened for MBL production by double disc synergy test (DDST) and minimum inhibitory concentration reduction test. There was complete correlation between two methods for imipenem. For ceftazidime, there was correlation between the two methods in all except four strains. In the screening test for MBL, ceftazidime-EDTA combination was better than imipenem-EDTA combination. 8.05% strains were MBL producers. Presence of MBL producer P. aeruginosa is a cause of concern. Simple DDST can be helpful for monitoring of these emerging resistant determinants.