Methicillin resistant Staphylococcus aureus colonisation: A three year experience with a surveillance program, in a tertiary neurocare centre

BackgroundMethicillin resistant Staphylococcus aureus (MRSA) is an important nosocomial pathogen. A strong correlation between the invasive and the nasal carriage strains in the patients has been well established indicating the need to eliminate the carriage of MRSA to prevent the transmission. The objectives of this study are to assess the prevalence of MRSA colonisation in patients from ICUs and high risk wards for a period of 33 months, (2011–2013) by routine active surveillance culture, and also to evaluate the role of extra-nasal sites in the screening.MethodsThe nasal and extra-nasal specimens were obtained from patients using sterile cotton swab. Staphylococci were identified based on colony morphology on blood agar, Gram's staining and coagulase test. The Staphylococcus aureus (S. aureus) isolates were screened for methicillin resistance by Kirby–Bauer disc diffusion method using oxacillin (1 μg) and cefoxitin (30 μg) discs and reported according to CLSI guidelines.ResultsOut of the 5372 nasal samples tested, S. aureus was identified in 14.1% patients. The rate of methicillin resistance was 31.7% of the total S. aureus isolates. The overall prevalence of MRSA was 4.5%.Out of 219 extra-nasal samples tested, 4.1% of the patients carried MRSA in sites like axilla and groin without nasal carriage.ConclusionOur results encourage us to continue with the screening program so as to prevent the high risk patients contracting endogenous infections thus controlling the transmission and spread and also the addition of extra-nasal site; either axilla or groin might increase the screening efficiency in non nasal colonisers.