Antibiotic susceptibility pattern and plasmid profiles of nasal staphylococci from apparently healthy Nigerians

A total of 480 nasal samples from apparently healthy Nigerian students were collected aseptically and analyzed bacteriologically. Staphylococci were recovered from 432 (90%) of the subjects, constituting 288 (66.7%) and 144 (33.3%) of S. aureus and S. epidermidis respectively. The in-vitro antibiotic susceptibility testing using the disc diffusion technique showed high multiple resistance to the most commonly used antibiotics by Staphylococcus aureus such as penicillin (98.6%), ampicillin (97.2%), tetracycline (95.8%) and streptomycin (84.7%), but less resistance to erythromycin (9.7%), rocephin (8.3%), peflacin (4.2%) respectively. The S. epidermis showed less resistance to all the antibiotics tested. Sixty percent of S. aureus harbored plasmids which molecular sizes ranged from 0.1 to 12.0 kilobases. The high prevalence of multiple antibiotic resistance appear to be plasmid mediated as plasmid profile analysis showed that about 90% of S. aureus harbored plasmids