Prevalence of Methicillin Resistant Staphylococcus aureus in Nasal Samples from Health Care Workers: Comparison of Cefoxitin and Oxacillin Disc Diffusion Methods

The anterior nares is the most frequent carriage site for Staphylococcus aureus. Methicillin resistant S.aureus (MRSA) are now the major hospital acquired pathogens worldwide. To know the prevalence of nasal carriage of S.aureus and MRSA among health care workers (HCWs) and to compare cefoxitin and oxacillin disc diffusion methods in detecting MRSA. Study was conducted on 102 HCWs of a tertiary care hospital consisting of 12 laboratory technicians, 37 staff nurses and 53 nursing students. Samples were collected from anterior nares using sterile cotton swab soaked in sterile saline. Swabs were processed without delay. S.aureus were identified by standard microbiological techniques. Detection of MRSA was done by cefoxitin and oxacillin disc diffusion method according CLSI 2011 guidelines. Highest S.aureus and MRSA carriage of 54.05% and 45.94% respectively was seen in staff nurses. S.aureus and MRSA carriage was 41.66% and 33.33% in laboratory technicians and 41.50% and 22.64% respectively in nursing students. Cefoxitin detected 33 and oxacillin detected 30 MRSA. Prevalence of nasal carriage of S.aureus and MRSA is very high in HCWs. Cefoxitin disc is superior to oxacillin disc in detecting MRSA. Continuous surveillance, decolonization of carriers and improvement of hygiene standards in hospital should be adopted to break the transmission of MRSA.