Prevalence of Methicillin- resistant Staphylococcus aureus and Coagulase- Negative Staphylococci among Male Students in a Private Tertiary Institution and their Enterotoxin-Producing Potential

In order to determine the prevalence and antimicrobial resistance among methicillin-resistant, methicillin-sensitive and coagulase-negative staphylococci in a tertiary institution, nasal swabs were collected from 100 male students. A total of 98 staphylococci were isolated, out of which 51 were coagulase positive. Methicillin resistance among the Staphylococcus aureus isolates was 25.5%. The carriage rate of methicillin-resistant coagulase-negative staphylococci among the subjects was 11%. Bacillus spp. was isolated in pure cultures from 5 subjects and of these isolates one was resistant to methicillin. Antimicrobial susceptibility of the methicillin- resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase negative staphylococci (MRCONS) isolates to various antibiotics tested showed that, in most cases, the MRSA were less susceptible to the antibiotics than MRCONS. None of the MRSA was resistant to vancomycin. There were no identified risk factors in this study. Twenty-six strains of Staphylococcus aureus isolates produced staphylococcal enterotoxins. Staphylococcal enterotoxin A (SEA) was produced by 21 strains (8 from the 13 MRSA isolates). Staphylococcus saprophyticus produced SEA (11 strains), SEB (2 strains) and SEC (2 strains).