Molecular characterization and antimicrobial resistance of bacterial pathogens in neonatal sepsis: A cross-sectional study at a Lagos tertiary hospital

Background: Neonatal sepsis, a high-risk disease, is a major contributory factor to infant morbidity and mortality in low- and middle-income countries. The aim of this study was to isolate and molecularly characterize bacterial pathogens causing sepsis in neonates. Methods: This study characterized and evaluated the antimicrobial susceptibility profile of the bacterial aetiology of neonatal sepsis in the neonatal ward of a tertiary hospital in Lagos. Ninety-five blood samples were collected from neonates presenting with sepsis. Microbiology and molecular biology methods were used for the identification and characterization of bacterial isolates, while antibiotic susceptibility testing was conducted using the Kirby-Bauer disc diffusion method. Results: Of the participants, 67.4% were between 1 day and 1 week old, and 86.3% had an onset of temperature between 1 day and 5 days. Twenty percent of the blood samples were culture positive, revealing 32% Gram-positive bacteria and 60% Gram-negative bacteria. There was no significant difference (p = 0.8374) in the rate of positive blood cultures between male and female participants. The dominant bacterial species identified were Enterobacter quasihormaechei and Enterobacter cancerogenus. Other isolated species included Bacillus aerius, Bacillus inaquosorum, Bacillus paramycoides, Klebsiella pneumoniae, Klebsiella variicola, Staphylococcus hominis, Staphylococcus saccharolyticus, and Cedecea colo. Notably, 95% of the isolates were resistant to cefuroxime, 89% to cefepime, and 74% to amoxicillin + clavulanic acid. Two isolates, AH-1 (Enterobacter roggenkampii) and ON-2 (Cedecea colo), were resistant to eight of the nine tested antibiotics. Conclusion: The high rate of multidrug-resistant bacterial strains implicated in neonatal sepsis underscores the need for routine surveillance and improved hygiene practices in neonatal wards.