Journal of Bioscience and Biotechnology Discovery

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of neonatal infections in both hospital and community settings. Identifying its sources and mechanisms of resistance is essential for effective control. This study investigated MRSA colonisation in mothers and their newborns and assessed whether resistance was plasmid-mediated. A total of 201 swab specimens were collected from 100 mothers and 101 babies using sterile swabs. Samples were cultured on mannitol salt agar and blood agar, and incubated at 37°C for 24 hours. Colonies were confirmed as S. aureus through standard bacteriological and biochemical tests. Antibiotic susceptibility testing was performed using the modified Kirby-Bauer disc diffusion method. Plasmid profiling was carried out on a 0.8% agarose gel for 10 methicillin-resistant isolates, and plasmid curing was attempted with sodium deodecyl sulphate. Seventy-four S. aureus isolates were recovered, of which 19 (25.7%) were resistant to methicillin. Eleven of these originated from neonates. All MRSA isolates demonstrated multidrug resistance. Plasmid analysis revealed differences between isolates from mothers and babies, suggesting both vertical and horizontal transmission. After curing, seven plasmid-bearing isolates showed altered antibiotic susceptibility, confirming a plasmid role in resistance. Two-way analysis of variance compared MRSA from neonates only, mothers only, and mother–baby pairs. At P>0.05, differences were insignificant; however, at P<0.05, MRSA from mother–baby pairs showed significant variation. This study highlights the high prevalence and multidrug resistance of MRSA in mothers and neonates. The findings emphasise the need for coordinated national surveillance, robust infection control measures, and strengthened antibiotic stewardship to reduce the growing burden of MRSA infections in Nigeria.