Genotypic Characterisation of Carbapenem-Resistant Enterobacteriaceae in a Tertiary Care Hospital in South India

Introduction The antimicrobial resistance of <i>Enterobacteriaceae</i> is variable and is influenced by both geographic location and regional antibiotic use. The overuse of antibiotics, especially in hospitalised patients, suppresses the growth and persistence of drug-resistant bacteria. This study aimed to detect the prevalence of carbapenem-resistant <i>Enterobacteriaceae</i> and the genes responsible for the resistance. Methods A cross-sectional study has been conducted over the course of two years, from October 2021 to September 2023. A total of 2,152 samples, including pus, blood, urine, sputum and various body fluids, were collected and subjected to study. All data were analysed and presented as frequency with percentage. Results Out of 2,152 samples, 659 (32.1%) samples showed growth. Among them, 250 (38%) were found to be <i>Enterobacteriaceae</i>, of which 22 (8.8%) were resistant to carbapenems. The isolates were <i>Escherichia coli</i> (nine, 40%) followed by <i>Klebsiella pneumoniae</i> (eight, 36%), <i>Morganella morganii</i> (two, 9%), <i>Klebsiella oxytoca</i> (one, 5%), <i>Proteus vulgaris</i> (1, 5%), and <i>Enterobacter cloacae</i> (1, 5%). NDM (14, 63.63%) was the most common gene detected from the isolates. Conclusion Our research leads us to the conclusion that resistance to carbapenem medication can result from either the generation of carbapenemase or from non-carbapenemase mechanisms like loss of porin channels or an increase in the efflux pump. According to our research, the primary source of carbapenem resistance is metallo-β-lactamase. Therefore, it is critical for all the laboratories to identify the mechanism and incidence of carbapenem resistance in order to support epidemiological research, infection control and antibiotic stewardship.