Detecting Carbapenem Resistance in Enterobacteriaceae Isolates Using Carbapenem Discs and the Modified Hodge Test at a Tertiary Care Hospital in Maharashtra, India

The emergence of carbapenem-resistant Enterobacteriaceae (CRE) poses a significant public health concern due to its potential for increased mortality and morbidity. The limited availability of effective antibiotics further exacerbates the dissemination of carbapenem-resistant bacteria. This study aimed to evaluate the prevalence of carbapenem resistance and carbapenemase production in Enterobacteriaceae isolates using the Modified Hodge Test.

This observational study was conducted at the Department of Microbiology, MGM Medical College & Hospital, Aurangabad, Maharashtra, from November 2015 to November 2017. 171 Enterobacteriaceae isolates from various clinical samples were comprehensively tested for carbapenem resistance and carbapenemase production. This involved the use of carbapenem discs (ertapenem, meropenem, and imipenem), E-test strips for ertapenem and meropenem, and the Modified Hodge Test (MHT) for carbapenemase identification.

Among the 171 tested Enterobacteriaceae isolates, a substantial proportion (40%) displayed resistance to carbapenems, as determined by disc diffusion and E-test methods. Among the carbapenem-resistant isolates, 13 were positive for the MHT.

Our study revealed a notable prevalence of carbapenem resistance in Enterobacteriaceae isolates from a tertiary care hospital. The MHT, following Clinical and Laboratory Standards Institute (CLSI) guidelines, demonstrated high sensitivity (> 90%) and specificity (> 90%) for detecting KPC-type carbapenemases in these isolates. Treatment options for CRE infections are limited, with tigecycline and colistin identified as potential options. Our study highlights the importance of promptly diagnosing different carbapenemases using PCR techniques. Consequently, we strongly advocate for implementing robust antimicrobial stewardship programs and infection control practices in healthcare settings to prevent CRE spread effectively.