Detection of Carbapenem-Resistant Genes Among Clinical Isolates of Acinetobacter baumannii in a Tertiary Care Hospital

TL;DR

This study identifies carbapenem resistance genes in Acinetobacter baumannii isolates from a hospital, highlighting the spread of drug-resistant bacteria.

Contribution

The study reports the prevalence and co-occurrence of specific carbapenem resistance genes in clinical isolates of A. baumannii.

Findings

blaNDM was detected in 35% of tested isolates.

blaOXA-48 was found in 30% of isolates.

Co-existence of blaNDM and blaOXA-48 was observed in 20% of isolates.

Abstract

Background

Acinetobacter baumannii, an opportunistic pathogen associated with healthcare-associated infections, poses a major clinical challenge due to its ability to develop resistance to multiple drugs, particularly carbapenems.

Objective

The aim of the study was to detect the presence of different carbapenem resistance genes in clinical isolates of Acinetobacter baumannii.

Materials and methods

A cross-sectional study was conducted from March 2023 to December 2023 in the Department of Microbiology of a tertiary care hospital, India. A total of 107 non-duplicate clinical isolates of Acinetobacter baumannii resistant to carbapenems were screened and collected. Bacterial species identification and antimicrobial susceptibility testing were performed using the VITEK 2 automated system (AST N405 panel). Carbapenem resistance genes were detected by real-time polymerase chain reaction (q-PCR) targeting blaNDM, blaOXA48, blaVIM, blaKPC and blaIMP genes using multiplex TRUPCR UTI AST Panel Kit. Data analysis was performed using Microsoft Excel (Microsoft Corp., Redmond, WA, USA), and the frequency of detected genes was expressed in percentages.

Result

Out of the 107 carbapenem-resistant A. baumannii isolates, 20 isolates were subjected to molecular detection of carbapenem-resistant genes. Out of the 20 isolates tested for resistance genes, blaNDM was detected in 35% (7/20) of the isolates, while blaOXA-48 was found in 30% (6/20). blaNDM+blaOXA-48 were found to co-exist in 20% (4/20) of the isolates. blaIMP+blaKPC, blaOXA48+IMP, blaIMP+blaNDM genes were found in one isolate each (5%, 1/20).

Conclusion

The detection of blaNDM and blaOXA-48 genes in carbapenem-resistant Acinetobacter baumannii highlights the growing threat of multidrug-resistant pathogens in clinical settings. The co-existence of these resistance genes underlines the need for routine molecular surveillance and stringent antimicrobial stewardship to prevent the spread of such high-risk clones.

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