Abstract
Background:
The spread of carbapenem resistant bacteria has caused grave concern due to the limited choice in antibiotics for treating infections caused by them. The emergence of metallo beta-lactamse (MBL) producing gram negative bacilli poses a therapeutic challenge and is of serious concern for infection control in hospital environment.
Materials & Methods:
A total of 475 non repeat clinical isolates of family Enterobacteriaceae were included in the study. Resistance to imipenem was determined in isolates by disc diffusion & minimum inhibitory concentration (MIC) method. Imipenem resistant isolates were tested for MBL production by combined disc diffusion test and modified Hodge test.
Results:
Out of the 475 Enterobacteriaceae strains, 20 showed resistance to imipenem. MBL activity was detected in all 20 (4.2%) isolates by combined disc diffusion test, in 18 isolates by modified Hodge test. The MBL producing isolates included clinical strains of Klebsiella spp (45%), E. coli (40%), Citrobacter spp (15%). Majority of the MBL isolates were from Intensive care unit (65%), from patients with comorbid conditions and with invasive devices. MBL producing isolates showed high level of resistance to aminoglycosides and fluoroquinolones but all were susceptible to colistin.
Conclusion:
The need of the hour is to detect MBL producing isolates for better patient outcomes, to execute prompt infection control measures and decrease the escalation of resistance.
Keywords: Imipenem resistance, Phenotypic methods, Colistin sensitivity