High nasal MRSA colonisation in healthy and septicemic under-five-year-old children in Zaria, Nigeria

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a high-priority bacterium and a significant global health threat that requires continuous surveillance, especially in vulnerable populations, such as children. This study determined the prevalence and antimicrobial resistance (AMR) profile of nasal S. aureus , as well as the factors associated with its presence, among healthy children (HC) in Zaria communities and septicemic children (SC) attending the Ahmadu Bello University Teaching Hospital (ABUTH), Nigeria. Materials and methods Nasal samples were collected from 71 HC and 40 SC from 2nd April to 30th July 2025. The samples were processed to recover and identify S. aureus , and to determine their AMR profiles using conventional bacteriological media and the automated VITEK II compact system. Pretested structured questionnaires were used to collect sociodemographic and epidemiological data from children's parents or guardians. Results: All the S. aureus were MRSA, and the nasal carriage was 27.9%, with 25.4% in HC and 32.5% in SC (OR = 1.42, 95% CI: 0.61–3.32, p = 0.4213). Use of antibiotics at least three months before sample collection was a significant factor for nasal MRSA colonisation in healthy children (OR = 137.19, 95% CI: 7.64-2464.38, p = 0.00008). MRSA carriage appeared to increase with age among healthy children, with a significantly higher prevalence among children aged 3 years than those aged 1 year (40% versus 20.6%, OR = 11.42, 95% CI: 1.09–120, p = 0.043). Resistance to non-beta-lactam antibiotics was highest against tetracycline (90.3%), mupirocin (83.9%), and sulfamethoxazole-trimethoprim (54.8%), with 87.1% exhibiting a multidrug-resistant phenotype. Remarkably, 32.2% and 22.5% of the MRSA were resistant to linezolid and vancomycin-teicoplanin, respectively. Over 50% of the MRSA had multiple AMR indices of 0.5. Conclusions: This study found no difference in nasal MRSA carriage between healthy and septicemic children. However, findings indicate a high prevalence multidrug-resistant-MRSA strains in both groups, highlighting potential implications for infection control measures in paediatric healthcare facilities in resource-limited settings.