While numerous studies examine the epidemiology and molecular characterization of Staphylococcus aureus in most developed countries, the detailed molecular characterization and molecular epidemiology of S. aureus strains and clones in Africa is lacking. We determined the molecular epidemiology and virulence of 81 non-duplicate isolates of S. aureus from Benin-City, Nigeria, collected during January–July 2016, and compared with global strains. Forty-seven isolates (58.0%) were found to be methicillin-sensitive Staphylococcus aureus (MSSA), while 34 (42.0%) were methicillin-resistant Staphylococcus aureus (MRSA). ST152-MSSA (24.7%) and ST7-MRSA-V (19.8%) were the dominant groups identified, which were not genetically related to global predominant strains, but rather exhibited regional dominance. An interesting finding of the study was the presence of highly related strains in the region, which differed primarily in their methicillin resistance gene carriage, staphylococcal cassette chromosome mec (SCCmec), with 99.4–99.7% relatedness between the genomes of the strains within the MRSA–MSSA pairs. This suggests that the strains within a pair are experiencing gain or loss of SCCmec within local conditions, with evolution continuing to diversify the strains to a small degree. This study represents the most comprehensive genetic and virulence study of S. aureus in Nigeria.

Water buffalo (Bubalus bubalis) are a primary source of milk in Pakistan, where bovine mastitis is a significant health issue among cattle, leading to substantial economic losses. Staphylococcus aureus is a predominant pathogen associated with mastitis; however, a detailed molecular characterization of the strains in the country remains limited. We previously characterized mastitis strains from the Hazara division of Khyber Pakhtunkhwa, Pakistan. In this study, we investigated mastitis cases in the Peshawar division, including samples from both animals and human farm workers for comparison. Higher rates of mastitis (67.27% of animals) and sub-clinical mastitis (91.03% of positive animals) were identified in Peshawar than for those (34.55% and 75.31%, respectively) previously observed in Hazara. Methicillin-susceptible S. aureus (MSSA) belonging to clonal complex 9 (ST2454) were predominant. Methicillin-resistant S. aureus (MRSA) belonging to ST22 and ST8 were also detected in the Nowshera district. While no S. aureus colonization was observed among animal handlers, evidence of hand contamination suggests a potential route for pathogen spread. Low levels of antibiotic resistance were noted amongst isolates, but higher rates were seen in MRSA. This study presents only the second comprehensive molecular investigation of S. aureus isolated from buffalo mastitis in Pakistan and indicates a concerning rise in mastitis within the province.