Prevalence and Risk Factors Associated with Nasal Colonizing Staphylococcus aureus among Cohorts of Nigerian University Students

Background: Nasal carriage of Staphylococcus aureus may provide a reservoir for transmission in university communities. Aim: This study examined carriage and antimicrobial susceptibility among students at Godfrey Okoye University, Enugu, Nigeria. Methods: Nasal swabs were collected from 250 participants, comprising 125 male and 125 female students. Students receiving antimicrobial treatment at the time of sampling were excluded. Isolates were cultured on mannitol salt agar and characterised using colonial and biochemical procedures. Antimicrobial susceptibility was assessed by disc diffusion, with cefoxitin used for phenotypic methicillin-resistance screening. Twenty phenotypically multidrug-resistant isolates were selected for PCR analysis targeting 16S rRNA and mecA. Results: S. aureus was recovered from 67 male participants (53.6%) and 69 female participants (55.2%), yielding 136 isolates. Of these, 130 showed resistance to at least one tested antibiotic, and 80 were resistant to three or more antibiotics. The multiple-antibiotic-resistance index exceeded 0.2 in 81 isolates. Among 670 recorded antimicrobial responses for male isolates, 262 were resistant, compared with 166 resistant responses among 690 observations for female isolates. The reported chi-square analysis found different distributions of susceptibility categories between the two groups. PCR findings indicated the presence of mecA-positive isolates within the selected subset. Conclusion: Nasal carriage and antimicrobial resistance occurred in both student groups. Molecular detection of mecA in selected isolates does not establish the prevalence of methicillin resistance across the full cohort. The findings support further laboratory surveillance and prudent antimicrobial use.