Emerging resistance to carbapenem among Gram-negative bacteria in a tertiary care hospital

Abstract

The emergence of bacterial antibiotic resistance is a cardinal concern in the health care system. The spread of resistance in Enterobacteriaceae and non-fermenters to the currently available drugs make the treatment of serious nosocomial infections troublesome.  The purpose of the study is to find out the carbapenem resistance among Gram-negative bacilli in a tertiary care hospital. Antibiotic susceptibility pattern of 1913 aerobic Gram-negative bacilli isolated from clinical samples was made for a period of 6 months. All the isolates were tested for susceptibility to antibiotics by the Kirby-Bauer disc diffusion technique according to CLSI guidelines. Carbapenemase production was confirmed by the Modified Hodge Test (MHT). Minimum Inhibitory Concentration (MIC) by Epsilometer (E) test was performed (for Imipenem and Meropenem) for carbapenem-resistant strains. A total of 1731 clinical samples, 1913 Gram-negative bacilli were isolated. 1476 (77.1%) were Enterobacteriaceae and 433 (22.6%) were non-fermenters. 54 were carbapenemase-producing Gram-negative bacilli. Meropenem E test was done for carbapenemase-producing Gram-negative bacilli. The minimum inhibitory concentration for Meropenem ranged from 0.002μg/ml to 32μg/ml. To overcome the problem of emerging resistance, combined interaction and cooperation of microbiologists, clinicians and the infection control team is needed.