# Characterization of Carbapenem-Resistant Gram-Negative Bacilli Isolates in Multispecialty Private Hospitals in Lagos, Nigeria

## TL;DR

This study found a high rate of carbapenem-resistant bacteria in Nigerian hospitals, highlighting the need for better treatment and surveillance strategies.

## Contribution

The study provides new data on carbapenem-resistant Gram-negative bacilli and their resistance patterns in Lagos, Nigeria.

## Key findings

- 29% of Gram-negative bacilli were carbapenem-resistant, with higher rates in ICU and oncology.
- 18.5% of CR-GNB were carbapenemase-producing, showing high resistance to ampicillin/sulbactam and trimethoprim/sulfamethoxazole.
- New Delhi Metallo-β-lactamase (blaNDM) was found in multiple species, including extensively and pandrug-resistant strains.

## Abstract

Background/Objectives: Carbapenem-resistant Gram-negative bacilli (CR-GNB) pose a growing challenge to public health worldwide due to limited treatment options. This cross-sectional study investigated the characteristics of CR-GNB isolated from clinical specimens in Lagos, Nigeria. Methods: Gram-negative bacilli (GNB) and clinical data were obtained from three multi-specialist private hospitals between March and June 2023. The GNB were identified using the Analytical Profile Index (API) and investigated for CR-GNB by disk diffusion. Antimicrobial resistance patterns and carbapenemase gene data for presumptive carbapenemase-producing Gram-negative bacilli (CP-GNB) were analyzed using Vitek-2 and polymerase chain reaction (PCR). Results: Of 317 GNB, 29.0% (n = 92) were CR-GNB. Significantly higher numbers of CR-GNB were reported from the intensive care unit and oncology department (p = 0.009). Of all CR-GNB, 17 isolates (18.5%) were classified as presumptive CP-GNB. In this subgroup, resistance rates of ampicillin/sulbactam (100.0%) and trimethoprim/sulfamethoxazole (100.0%) were highest. Ten (10) CP-GNB were confirmed, representing 3.15% of all GNB tested. Seven isolates of New Delhi Metallo-β-lactamase (blaNDM) were found among P. aeruginosa, K. pneumoniae, E. coli, and A. baumannii. The blaNDM was identified in strains classified as extensively drug-resistant (XDR) and pandrug-resistant. Conversely, the blaKPC was detected solely in multidrug-resistant and XDR strains. Conclusions: Emerging CR-GNB, specifically CP-GNB, in Nigeria emphasize the need for specific therapeutic management of infected patients. Antimicrobial stewardship and long-term surveillance efforts must be implemented in healthcare settings, as well as improved, accelerated microorganism identification techniques.