Molecular Characterization of Hospital-Acquired Carbapenem-Resistant Gram-Negative Pathogenic Bacteria From a Tertiary Hospital in Lagos State, Nigeria

Background: Carbapenem-resistant gram-negative bacteria are major challenges in antibiotic therapy globally due to their innate ability to cause life-threatening diseases, leading to treatment failure, high morbidity and mortality, and an increase in hospital-acquired infections. Nonetheless, limited studies exist on their molecular characterization in Nigeria. Accordingly, this study aimed to identify the distinct strains of hospital-acquired carbapenem-resistant gram-negative bacteria from a tertiary hospital in Lagos, Nigeria, using molecular characterization. Methods: Bacteria isolates from the cultures of in-patients’ samples were identified phenotypically by selective/differential diagnostic media and biochemical tests based on standard microbiological protocols. Carbapenem resistance was determined using the Kirby-Bauer disc diffusion method. The isolates of carbapenem-resistant bacteria were characterized using 16S rRNA nucleotide sequencing. Their nucleotide sequences were analyzed using the Basic Local Alignment Search Tool, and accession numbers were assigned to them from the NCBI GenBank. Results: A total of 162 gram-negative bacteria were isolated based on the results. Among them, 13 (8%) were carbapenem-resistant, and 10/13 of the carbapenem-resistant bacteria were molecularly characterized. The molecularly characterized carbapenem-resistant bacteria had 99.38%, 99%, and 98.85% gene similarity indices to Escherichia coli (PP808947), Klebsiella pneumoniae (PP808950), and Pseudomonas aeruginosa (PP808949), respectively. They also showed 98.71%, 98.53%, 98.26%, and 97.80% gene similarity indices to Enterobacter hormaechei (PP808946), E. hormaechei (PP808945), Alcaligenes faecalis (PP808944), and Providencia stuartii (PP808942), respectively. E. coli was the most predominant molecularly characterized hospital-acquired carbapenem-resistant gram-negative strain. Conclusion: This study provided knowledge of the phenotypes and genotypes of hospital-acquired carbapenem-resistant gram-negative Enterobacterales in the study population. It is recommended that these molecularly characterized gram-negative bacteria be monitored in hospitals through effective infection control programs to mitigate their disease outbreak.