Multidrug-resistant Staphylococcus aureus associated with neonatal sepsis in the special care baby unit of a secondary healthcare facility in Katsina State, Nigeria: Staphylococcus aureus multirésistant associé à une septicémie néonatale dans l'unité de soins intensifs néonatals d'un établissement de soins de santé secondaires de l'État de Katsina, au Nigéria

Background: Neonatal sepsis remains a major cause of morbidity and mortality in developing countries, with Staphylococcus aureus being one of the leading causative organisms. The rising occurrence of multidrug-resistant (MDR) strains poses significant therapeutic challenges. This study aimed to determine the antibiotic resistance pattern and multiple antibiotic resistance (MAR) index of S. aureus isolated from neonatal sepsis cases in the Special Care Baby Unit (SCBU) of a secondary healthcare facility in Katsina State, Nigeria.Methodology: A hospital-based cross-sectional study was conducted involving 155 neonates with suspected sepsis. Blood samples were aseptically collected and cultured using standard microbiological techniques. Staphylococcus aureus isolates were identified through colony morphology, Gram staining, and biochemical tests. Antibiotic susceptibility test was performed using the Kirby-Bauer disk diffusion method in accordance with Clinical Laboratory Standards Institute (CLSI) guidelines. Multi-drug resistance was defined as resistance of an isolate to three or more classes of antibiotics. The MAR index for each isolate was calculated as the ratio of the number of antibiotics resisted to the total number tested.Results: Of the blood samples analyzed for 155 clinical neonatal sepsis cases, 65 (41.9%) were culture-positive for bacterial pathogens, with 31 (20.0%) S. aureus isolates, which exhibited high resistance to erythromycin (87.0%), cefoxitin (83.0%), ampicillin (64.0%) and gentamicin (64.0%). Although resistance to imipenem was lowest at 51.0% among the antibiotics tested, this value still indicated a relatively high resistance rate. Overall, MDR was detected in 74.0% of the isolates, indicating high AMR burden among S. aureus associated with neonatal sepsis. Among the isolates, 83.9% were methicillin-resistant S. aureus (MRSA) while 64.5% were gentamicin resistant S. aureus (GRSA). The MAR index of the S. aureus isolates ranged from 0.2 to 1.0, with a mean value of 0.7±0.3, but most isolates (93.5%) exhibited MAR index values higher than 0.2.Conclusion: The high prevalence of MDR and high MAR index values among S. aureus isolates indicate significant antibiotic selection pressure within the SCBU of the facility studied. Strengthened antimicrobial stewardship and routine AMR surveillance are urgently required to improve neonatal sepsis outcomes.