Phenotypic detection of carbapenem-resistant Enterobacterales in clinical isolates at a tertiary care hospital

Abstract

Abstract Background: In the past decade, there has been a global emergence of carbapenem-resistant Gram-negative bacilli, especially Enterobacterales. Carbapenem resistance is attributed to the ability of the bacteria to produce carbapenemases. The aim of the study is to detect carbapenem-resistant Enterobacterales (CRE) in different clinical isolates and study carbapenemase production by phenotypic methods in CRE. Materials and Methods: A total of 379 Enterobacterales were isolated from different clinical samples from patients attending outpatient departments and admitted in wards and intensive care units (ICUs). They were tested for carbapenem resistance by Kirby–Bauer disk diffusion method and then tested for carbapenemase production by ethylenediaminetetraacetic acid (EDTA)–disk synergy test and Modified Carbapenem Inactivation Method (mCIM). Results: This study was conducted from February 2021 to August 2022. Out of 379 Enterobacterales, 70 (18.47%) were CRE, out of which maximum carbapenem resistance of 23.53% was shown by Klebsiella pneumoniae isolates. The maximum carbapenem resistance was seen in the age group of 16–45 years and the most number of CRE isolates were from ICUs. Phenotypic test results indicated that 54.28% (38/70) of isolates were positive for carbapenemase production by either of the phenotypic methods. Conclusion: About one-fifth of the Enterobacterales isolates were carbapenem resistant. This study highlights the use of phenotypic methods to detect carbapenemase production in CRE, which is responsible for multidrug resistance. This information is relevant for surveillance, to implement infection prevention and control practices and antibiotic policies.