Optimization of multiple muco-cutaneous site sampling method for screening MRSA colonization in ICU

AIMS: Active screening for methicillin resistant Staphylococcus aureus (MRSA) carriers remains a vital component of infection control policy in any health-care setting. The relative advantage of multiple anatomical site screening for detecting MRSA carriers is well recognized. However, this leads to increase in financial and logistical load in a developing world scenario. The objective of our study was to determine the sensitivity of MRSA screening of nose, throat, axilla, groin, perineum and the site of catheterization (central line catheter) individually among intensive care unit patients and to compare it with the sensitivity of multiple site screening. MATERIALS AND METHODS: Active surveillance of 400 patients was done to detect MRSA colonization; 6 sites-nose, throat, axilla, perineum, groin and site of catheter were swabbed. RESULT AND DISCUSSION: The throat swab alone was able to detect maximum number of MRSA (76/90) carriers, with sensitivity of 84.4%. Next in order of sensitivity was nasal swab, which tested 77.7% of MRSA colonized patients. When multiple sites are screened, the sensitivity for MRSA detection increased to 95%. CONCLUSIONS: We found that though throat represent the most common site of MRSA colonization, nose or groin must also be sampled simultaneously to attain a higher sensitivity.