Prevalence of Carbapenem Resistance among Gram-Negative Bacteria in a Tertiary Care Hospital in North-East India

Abstract

Introduction: Carbapenems are considered to be the last choice for drug resistant Gramnegative bacteria but emergence of carbapenem resistant Gram-negative bacteria worldwide due to the production of carbapenemase has jeopardize their use. Aims and objectives: To detect the prevalence of carbapenem resistance in Gram-negative bacteria and carbapenemase production by Modified Hodge Test. Materials and Methods: A total of 160 isolates of Gram-negative bacteria from November 2012 to October 2014, from different clinical samples were included in the study. Those isolates with intermediate or resistant zone to meropenem and doripenem by disc diffusion methods according to CLSI guidelines were confirmed by E-test and were again tested for carbapenemase production by Modified Hodge Test (MHT). Results: Out of 160 isolates, 48 (30%) showed resistance to carbapenem by disc diffusion and E-test. Carbapenem resistance was higher in female patients 41.6% than in male patients 15.5% and among ICU patients 57.1%, ward patients 33.3% and among OPD patients 13.8%. Maximum number of carbapenem resistant isolate was obtained from urine sample n= 20, followed by pus n=13 and wound swab n=7. MHT for carbapenemase production was positive in 29 (60.4%) of the isolates. Carbapenemase production by MHT was highest with Acinetobacter spp. with n=5 (83.3%), followed by Pseudomonas spp. n= 6 (75%) and E.coli spp. n=16 (65.5%) and nil among Citrobacter spp. Conclusions: Carbapenem resistance due to production of carbapenemase is prevalent in our hospital. MHT is a simple test in the routine lab for detection of carbapenemases.