Detection of carbapenemase production in Enterobacterales by mCIM and eCIM: a tertiary care hospital study

Touseefa Shafi; Anjum Ara  Mir; Shagufta  Roohi; Bashir  Fomda; Sanam Rasool  Wani; Tufail  Ahmed; Samiah  Yousuf

doi:10.18502/ijm.v17i4.19227

Touseefa Shafi Department of Microbiology, Sher-i-Kashmir Institute of Medical Sciences, Soura, Jammu & Kashmir, India
Anjum Ara Mir Department of Microbiology, Sher-i-Kashmir Institute of Medical Sciences, Soura, Jammu & Kashmir, India
Shagufta Roohi Department of Microbiology, Sher-i-Kashmir Institute of Medical Sciences, Soura, Jammu & Kashmir, India
Bashir Fomda Department of Microbiology, Sher-i-Kashmir Institute of Medical Sciences, Soura, Jammu & Kashmir, India
Sanam Rasool Wani Department of Microbiology, Sher-i-Kashmir Institute of Medical Sciences, Soura, Jammu & Kashmir, India
Tufail Ahmed Department of Microbiology, Sher-i-Kashmir Institute of Medical Sciences, Soura, Jammu & Kashmir, India
Samiah Yousuf Department of Microbiology, Sher-i-Kashmir Institute of Medical Sciences, Soura, Jammu & Kashmir, India

DOI: https://doi.org/10.18502/ijm.v17i4.19227

Keywords: Carbapenem antibiotics; Carbapenemases; Beta-lactamases; Metallo-beta-lactamase; Microbial sensitivity tests

Abstract

Background and Objectives: Carbapenem-resistant Enterobacterales (CRE) pose a major healthcare challenge due to high resistance rates and limited treatment options. This study characterized carbapenemase production among CRE isolates using phenotypic methods—Modified Carbapenem Inactivation Method (mCIM) and EDTA-Carbapenem Inactivation Method (eCIM)—as genotypic methods have limitations like restricted gene targets and mutations.

Materials and Methods: This six-month study was conducted at Sher-i-Kashmir Institute of Medical Sciences (SKIMS). Samples including swabs, respiratory specimens, pus, body fluids, and blood were cultured on Blood Agar and MacConkey Agar (HiMedia, India). Enterobacterales were identified using conventional methods and screened for carbapenem resis- tance. CRE isolates underwent mCIM and eCIM testing per CLSI guidelines.

Results: Among 471 Enterobacterales isolates tested, 160 (33.9%) were carbapenem-resistant. Of these, 97 (60.6%) were mCIM positive, indicating carbapenemase production. eCIM further identified 83 (85.5%) as metallo-beta-lactamase (MBL) producers and 14 (14.4%) as serine carbapenemase producers. CRE prevalence was higher in ICU settings and among males. Isolates showed high cephalosporin resistance, with multi-drug resistance (MDR) common in both MBL and serine carbap- enemase producers.

Conclusion: The prevalence of CRE was found to be 33.9%. The findings underscore the critical need for continuous surveillance and stringent infection control measures to manage the spread of CRE in healthcare settings