Detection of Carbapenemase producing Enterobacteriaceae by modified Hodge test

Introduction: Increasing rates of antimicrobial resistance have become a worldwide problem predominantly caused by Gram-negative bacteria, especially by the family of the Enterobacteriaceae. As a result, more patients need antimicrobial treatment using so called ‘last resort’ agents “The Carbapenems.” This has resulted widespread carbapenem resistant mainly due to Carbapenemase enzymes. Their identification is of primary importance since carbapenemase producers are resistant not only to most (if not all) β-lactams but also to other main classes of antibiotics. The Modified Hodge Test (MHT), is a CLSI recommended, phenotypic test for detection of carbapenemase activity. Aims and Objectives: The present study was undertaken to determine Carbapenemase resistance in Enterobacteriaceae from various clinical samples by Modified Hodge Test, a phenotypic method. Materials and Methods: The present study was conducted in Department of Microbiology, Government Medical College and Associated group of hospitals, Kota (Raj.). One hundred consecutive, nonrepetitive Enterobacteriaceae isolates were processed for the study during the period of one year from September 2014 to August 2015. Antibiotic susceptibility test was performed by Kirby baeur method according to CLSI guidelines and the meropenem resistant isolates were further tested for Carbapenemase production by Modified Hodge Test (MHT). Observation and Results: Among 100 enterobacteriaceae isolates 24 showed reduced susceptibility (intermediate or resistant) to Carbapenem. Carbapenem resistance was highest in klebsiella spp. (46.7%) followed by Enterobacter spp. (25%). and E. coli (16.1%).None of proteus spp. and citrobacter spp were carbapenem resistant. Modified hodge test was done on carbapenem non susceptible Enterobacteriaceae isolates, which detect Carbapenemase production in 18 (75%) of carbapenem resistant isolates. Conclusion: To conclude, Carbapenemase producing Enterobacteriaceae isolates were relatively high in our institution. Accurate and timely detection of carbapenemase has important implications for efficient infection control and help in reducing the emergence of resistance thus decreases the morbidity and mortality rate.