# Detection of carbapenem resistance and its attributable genes in Acinetobacter baumannii isolated from cardiac patients at a referral cardiac hospital of Kathmandu

## TL;DR

This study found high rates of carbapenem resistance in Acinetobacter baumannii from cardiac patients in Kathmandu, with specific resistance genes commonly co-occurring.

## Contribution

The study reports the prevalence of carbapenem resistance and identifies co-occurring resistance genes in A. baumannii isolates from a cardiac hospital in Nepal.

## Key findings

- 88.1% of A. baumannii isolates were resistant to carbapenems.
- blaOXA-23 and blaNDM-1 genes were most commonly detected, with frequent co-occurrence.
- Multidrug resistance was observed in 83.3% of isolates.

## Abstract

Acinetobacter baumannii has emerged as a major nosocomial pathogen due to its remarkable ability to develop resistance to multiple antibiotics including carbapenems. The objective of this study was to assess the carbapenem resistance and detect carbapenem-resistant genes in clinical isolates of A. baumannii.

A cross-sectional study was conducted in Shahid Gangalal National Heart Centre, Kathmandu during February to September 2024. A total of 42 A. baumannii were isolated from different clinical specimens and identified. Antibiotic susceptibility test was performed by Kirby-Bauer disc diffusion method and carbapenemase production was assessed using modified carbapenem inactivation method and EDTA-carbapenem inactivation method. Carbapenem-resistant genes were detected through polymerase chain reaction. Among 1607 samples tested, 349 were culture positive for bacteria.

The prevalence of A. baumannii was 12% (42/349). Among the 42 A. baumannii isolates, 88.1% were resistant to carbapenems. Metallo-β-lactamase production was observed in 35.7% and multidrug resistance in 83.3% isolates. Resistance rates were highest against cefotaxime, cefepime and carbapenems. The blaOXA-23 gene was detected in 69.1% of the isolates, blaNDM-1 in 66.7%, and blaVIM in 14.3%, but none of the isolates harbored the blaIMP. Co-occurrence of blaOXA-23 and blaNDM-1 genes was detected in 20 (47.6%) isolates, blaOXA-23, blaNDM-1 and blaVIM in 4 (9.5%) isolates, and blaNDM-1 and blaVIM in 1 (2.4%) isolate.

This study showed a high burden of carbapenems resistant and multi-drug resistant A. baumannii, likely contributed by the co-occurrence of carbapenem resistant genes. These findings provide valuable insights for clinical management and infection control of A. baumannii.

The online version contains supplementary material available at 10.1186/s12866-025-04692-z.