Detection and prevalence of the bla     gene in carbapenem-resistant   Klebsiella pneumoniae bloodstream isolates from a tertiary care institute

Susheem  Ramakrishnan; Gulnaz  Bashir; Nargis Kaur  Bali; Sabah  Rashid; Dona  Mathew; Qounser  Nisar; Mohd Iqbal  Mir

doi:10.18502/ijm.v18i1.20902

Susheem Ramakrishnan Department of Microbiology, Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar, J&K, India
Gulnaz Bashir Department of Microbiology, Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar, J&K, India
Nargis Kaur Bali Department of Microbiology, Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar, J&K, India
Sabah Rashid Department of Microbiology, Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar, J&K, India
Dona Mathew Department of Microbiology, Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar, J&K, India
Qounser Nisar Department of Microbiology, Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar, J&K, India
Mohd Iqbal Mir State-Level VRDL Laboratory, Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar, J&K, India

DOI: https://doi.org/10.18502/ijm.v18i1.20902

Keywords: Carbapenemase; Beta-lactamase; New Delhi metallo-beta-lactamase; Klebsiella pneumoniae; Polymerase chain reaction; Bloodstream infections; Sepsis

Abstract

Background and Objectives: Carbapenem resistance mediated by bla NDM-1 in Klebsiella pneumoniae has emerged as a ma- jor challenge, particularly in intensive care settings with high antibiotic pressure. This compromises therapeutic options and contributes to poor clinical outcomes. The present study aimed to determine the prevalence of bla NDM-1 among isolates of K. pneumoniae from a tertiary care hospital, evaluate the performance of phenotypic tests against PCR-based detection, assess antimicrobial susceptibility profiles, and analyze clinical outcomes.

Materials and Methods: In this study, over 18 months, 130 non-duplicate K. pneumoniae isolates were identified, and antimicrobial susceptibility testing was performed by VITEK-2 Compact and broth microdilution for colistin. Imipenem-re- sistant isolates were subjected to the Combined disc diffusion test (CDDT) and Double disc synergy test (DDST) for metal- lo-beta-lactamase (MBL), and conventional PCR targeting bla . Demographic data and outcomes were recorded.

Results: Of the 130 isolates, 111 were imipenem-resistant, of which CDDT detected MBLs in 94.6%, and DDST detected MBLs in 76.6%. PCR confirmed bla NDM-1 in 77.5% and was more commonly associated with cases of sepsis. bla NDM-1 -posi- tive isolates were resistant to β-lactams, fluoroquinolones and aminoglycosides. No isolate was found to be colistin-resistant. 26.7% of the patients with bla -positive bacteremia died.

Conclusion: This study highlights the high prevalence of bla NDM-1 in K. pneumoniae isolates. Among the phenotypic tests, CDDT outperformed DDST and showed the best agreement with PCR, supporting its use as a screening method for MBL, but confirmatory PCR remains essential. The restricted treatment options underscore the need for stringent infection control and robust antimicrobial stewardship to curb transmission and preserve last-line agents.