Extensive multidrug resistance of coagulase-negative staphylococci in medical students

Staphylococcus aureus and coagulase-negative staphylococci (CNS) isolated from the nasal mucosa of medical students were examined for susceptibility to 16 antimicrobial agents. No methicillin-resistant S. aureus (MRSA) was isolated, while MRCNS was present in 23.5% of the medical students. CNS exhibited significantly more resistance to antimicrobial agents such as gentamicin, in addition to oxacillin, compared to S. aureus, and 13.1% of the CNS strains (mostly MRCNS) were multidrug-resistant (to five or more drugs). In contrast, ampicillin resistance was higher in S. aureus. The rate of hospitalization or of taking an antimicrobial agent within the past 1 year was lower in CNS+ students than in S. aureus+ students. The data suggest that CNS could serve as a reservoir of drug resistance by persistent colonization in the nasal mucosa. In this study, MRCNS with multidrug resistance was found in medical students. More attention should be given to nasal MRCNS in medical students as a possible spreader in hospitals.