Year: 2026 | Month: July-September | Volume: 11 | Issue: 3 | Pages: 105-113
DOI: https://doi.org/10.52403/ijshr.20260313
Unveiling the Silent Threat: Phenotypic and Molecular Characterization of Carbapenem-Resistant Acinetobacter baumannii in a North Indian Tertiary Healthcare Facility
Shaili Jaiswal1, Nikhil Raj2, Anupam Das3, Prachi Chauhan4, Manodeep Sen5, Jyotsna Agarwal6
1Senior Resident, Department of Microbiology, Autonomous State Medical College, Shahjahanpur
2Assistant Professor, Department of Microbiology, Sanjay Gandhi Post Graduate Institute, Lucknow
3Professor, Department of Microbiology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow
4Assistant Professor, Department of Pharmacology, Autonomous State Medical College, Pilibhit
5Professor, Department of Microbiology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow
6Professor & Head, Department of Microbiology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow
Corresponding Author: Dr. Anupam Das
ABSTRACT
Background: Acinetobacter baumannii is a critical nosocomial pathogen known for its multidrug resistance, particularly to carbapenems. To control the spread of A. baumannii in a healthcare facility, it is essential to understand its molecular epidemiology. This study compares different phenotypic and molecular techniques to detect these enzymes among carbapenem-resistant A. baumannii (CRAB) isolates, aiming to improve infection control and treatment strategies.
Methods: Over 18 months, 209 Acinetobacter isolates from various clinical specimens were analyzed at Dr. Ram Manohar Lohia Institute of Medical Sciences. Phenotypic methods included the Modified Hodge Test (MHT), Modified Carbapenem Inactivation Method (mCIM)for carbapenemases, and combined disk diffusion test (CDDT) and E-test for MBL detection. Genotypic characterization of 20 CRAB isolates was performed using the Carbapenemase Gene Detection kit.
Results: Of the 209 isolates, A. baumannii was the most common (89%) isolate, with 93% isolates showing carbapenem resistance. The mCIM detected carbapenemase production in 56.89% of isolates, compared to 26.43% by MHT. MBL production was identified in 35.6% of isolates by CDDT and 100% by E-test. All isolates harboured blaOXA-51 and blaOXA-23 genes, with blaNDM-1, blaIMP-1, and blaVIM detected in 90%, 40%, and 10% of isolates, respectively. Colistin demonstrated a high susceptibility rate of 82.2%, while minocycline showed a susceptibility rate of 23%.
Conclusions: The high carbapenem resistance in A. baumannii isolates, underscore the need for rapid and accurate detection methods. Despite high resistance rates, colistin and minocycline remain viable treatment options for CRAB.
Keywords: Acinetobacter baumannii, Carbapenem resistance, Carbapenemases, Metallo--lactamases, Multidrug-resistant