Efficacy of Modified Hodge Test for Phenotypic Confirmation of Carbapenemase Producing Gram-Negative Bacteria from ICU in a Tertiary Care Hospital

Resistance among bacteria isolates in the leading cause of increased mortality and morbidity worldwide. Carbapenems once thought to be effective are becoming ineffective mostly due to the emergence of carbapenemase. The present study was performed in the Department of Microbiology Bombay Hospital, Indore (MP) from January 2015 to may 2015 to determine the most prevalent organism to show carbapenem resistant along with the efficacy of modified Hodge test (MHT) for detection of carbapenemase production in Gram-negative bacteria (GNB). A total of 160 GNB from different clinical samples namely urine, pus, sputum, endo trachea and blood were isolated. By disc diffussion method, the isolates which showed intermediate or susceptible zones that is 16 mm–21 mm were subjected to MHT. Out of 160 isolates, 100 (62.5%) isolates were positive for carbapenemase production by MHT. Organism-wise distribution of organism was Klebsiella pneumoniae 107 (66.8%), Escherichia coli 15 (9.3%), Pseudomonas spp 28 (17.5%) and Acinetobacter spp 10 (6.25%). The sensitivity of various carbapenam was namely Ertapenem 10 (6.25%), Tmepenem 100 (62.5%) and Merupenam 50 (31.2%). Most of the weak positive results were shown by K. pneumoniae 6 (5.6%) out of 107 samples. There was a very high percentage of carbapenemases producing Gram-negative rods. It is imperative that all isolates showing intermediate or sensitive zone diameter on disc diffusion be further tested for production of carbapenemases by MHT to avoid treatment failures and development of resistance due to unnecessary use of this class of antibiotic.