Study of nasal carriage of MRSA among the clinical staff and health care workers of a teaching hospital of Karnataka, India

Objective: The present study was conducted to evaluate the rate of nasal carriage of Methicillin Resistant Staphylococcus aureus among the clinical staff and health careworkers working at our hospital with an aim to prevent the hospital acquired infections. Background: Methicillin resistant Staphylococcus aureus colonisation precedes infection, anterior nares being the ecological niches of Staphylcoccus aureus. Carriage of Staphylococcus aureus in the nose appears to play a key role in the epidemiology and pathogenesis of infection. Methicillin resistant Staphylococcus aureus is usually introduced into an institution by a colonised or infected patient or a healthcare worker.When nose is treated topically to eliminate nasal carriage, in most cases the organism also disappears from other areas of the body like groin, axilla, umbilicus, and hands. Methods: A total of 200 nasal swabs were collected, out of which 140 were from the nursing staff and 60 were from clinical staff. Sterile cotton swabs moistened with sterile saline were used for sample collection. Swabs were cultured on to blood agar, and mannitol salt agar, incubated at 37 oC for 24 hrs. Staphylococcus aureus was identified by standard methods according to CLSI guidelines. Methicillin resistance was detected by using cefoxitin disc 30µgm on Mueller Hinton agar with 4% NaCl. Results: Of the 200 samples screened 45 (43.6%) strains of Staphylococcus aureus were isolated, out of which 24 (12%) were. Methicillin resistant Staphylococcus aureus (MRSA) and 21 (10%) were methicillin sensitive Staphylococcus aureus (MSSA). The overall carriage rate of methicillin resistant Staphylococcus aureus in our study was 12% with the highest rate being seen among the nursing staff (12.2%) and clinical staff carriage rate was slightly less (11.7%) as compared to the nursing staff. Conclusion: Our study revealed that nursing staff were the potential colonisers of methicillin resistant Staphylococcus aureus when compared to clinical staff. These carriers may serve as reservoir and disseminator of MRSA, and should be treated with mupirocin 3 times daily for 5 days. So regular screening of carriers is required for the prevention of nosocomial infection