Nasal Carriers of Staphylococcus aureus and Its Recolonisation Rate After Mupirocin Treatment Among Medical Students in Nepal

Abstract

Introduction : Methicillin-resistant Staphylococcus aureus, a known cause of localized and fatal infections, are usually the normal inhabitants of anterior nares and skin. Healthy carriers harboring MRSA strains are responsible for nosocomial and community outbreaks as they interface between the healthcare centers and the community. MRSA is a threat to clinicians as they are resistant to many antibiotics. Besides using antibiotics to treat MRSA strains, an intervention using mupirocin ointment is followed to minimize the transmission of these strains. However, the rise in mupirocin resistance has been increasing. Hence, this study determined the frequency of S.aureus carriers among medical students and the recolonization rate after using 2% topical mupirocin.

Methods : Nasal swabs from 200 medical students of a tertiary care hospital in Nepal were collected and cultured on mannitol salt agar. S. aureus isolates were identified using standard microbiological procedures. Both MRSA and mupirocin-resistant S. aureus (MupRSA) isolates were identified using the Kirby-Bauer disk diffusion method.  S. aureus carriers were topically decolonized using 2% mupirocin ointment and recolonization of the carriers was further assessed monthly for the next 3 months.

Results : A total of 39 S.aureus were recovered from the anterior nares of the participants. Of these, 25 (64.1%) were methicillin-sensitive strains and 14 were MRSA strains (35.89%). None of them were MupRSA carriers.100% decolonization was achieved after nasal decontamination with 2% mupirocin ointment. However, 6 and 13 S.aureus recolonization cases were noted in the second and third month respectively, out of which, only one MRSA strain was seen in the second month and 4 MRSA strains were isolated in the third month.

Conclusion : Due to the continuous exposure of medical students to the hospital environment, they are at higher risk of MRSA colonization. Regular identification and decolonization strategies of the carriers must be implemented to reduce the rate of infection as well as its transmission.