Carbapenemase-Producing Enterobacterales: Distribution and Evaluation of Phenotypic Detection Methods Among Carbapenem Resistant Enterobacterales

Abstract

Background: Carbapenem-resistant Enterobacterales (CRE) represent a critical global health challenge due to resistance to last-line antibiotics and their involvement in hospital-acquired infections. Rapid detection of carbapenemase-producing Enterobacterales (CPE) is essential for guiding therapy and preventing transmission, particularly in resource-limited settings where molecular diagnostics are not routinely available.

Methods: A hospital-based cross-sectional study was conducted over the period of 1 year at a tertiary care centre. A total of 227 clinical isolates of CRE were processed using standard microbiological methods.Phenotypic assays, including Modified Hodge Test (MHT), EDTA inhibition test, and Boronic acid inhibition test, were employed to detect carbapenemase production among carbapenem-resistant isolates.

Results: Of the 227 CRE isolates, most were recovered from urine (53.3%), followed by pus (12.3%), pus swabs (10.1%), and respiratory specimens. Escherichia coli (66.08%) was the predominant isolate, followed by Klebsiella pneumoniae (16.74%) and Enterobacter spp. (4.41%). Specialty-wise, the majority of isolates originated from ICU (25.99%) and general medicine wards (22.03%). Phenotypic detection revealed the highest positivity with MHT (88.6%), followed by EDTA inhibition test (66.9%) and Boronic acid inhibition test (15%).

Conclusion: The study highlights the predominance of E. coli and K. pneumoniae among CRE isolates, with urine as the most frequent specimen source. Among phenotypic methods, MHT showed the highest detection efficiency, while the EDTA test was useful for identifying metallo-β-lactamase producers. Early phenotypic detection remains vital for effective management and infection control, especially in settings with limited molecular facilities.