Detection of Carbapenem-resistant Genes Associated with Hospital-acquired Gram-negative Bacterial Pathogens from A Tertiary Hospital in Lagos, Nigeria

Aims: To determine carbapenem-resistant genes associated to hospital-acquired Gram-negative bacteria pathogens from a tertiary hospital in Lagos, Nigeria.

Study Design: Prospective cross-sectional study.

Place and Duration of Study: Lagos State University Teaching Hospital Ikeja, Lagos and Nigerian Institute of Medical Research (NIMR), Lagos, between February 2023 and April 2024.

Methodology: We collected 162 Gram-negative bacteria isolates from urine and wound cultures of patients suspected of having hospital-acquired infections. Phenotypic identification of the isolates was by standard microbiological procedures. Carbapenem resistance was determined by Kirby-Baurer disc diffusion method using Meropenem and Imipenem. Confirmation of the strains of carbapenem-resistant bacteria isolates was by gene sequencing. The carbapenem-resistant genes of the bacterial strains were detected by conventional Polymerase Chain Reaction (PCR) using carbapenemase primers.

Results: Out of 162 bacterial isolates, 13(8%) bacterial isolates were resistant to Meropenem and Imipenem. New Dehli Metallo-β-lactamase (blaNDM) was detected in 6(46%) of the carbapenem-resistant isolates while Verona integron-encoded Metallo-β-lactamase (blaVIM) was detected in 2(15%). Carbapenemase genes were detected in 54% (7/13) of the carbapenem-resistant isolates. A strain of Enterobacter hormaechei harboured blaVIM and blaNDM genes.

Conclusion: The presence of these carbapenem-resistant genes in these pathogens is a public health threat. This study has provided knowledge of carbapenem-resistant genotypes of hospital-acquired bacterial pathogens in the study population. There should be renewed clinical monitoring of these pathogens and further studies on other mechanisms of carbapenem resistance.