The impact of active surveillance in the reduction of HA-MRSA infections in a tertiary acute care hospital in Singapore

Background: Hospital-acquired infection due to methicillin-resistant Staphylococcus aureus (HA-MRSA) is endemic in hospitals around the world despite concerted efforts by infection control professionals.  As in most hospitals in Singapore, about 50% of all Staphylococcus aureus isolates are MRSA in Singapore General Hospital (SGH).  Despite implementation of usual Contact Precautions on clinically identified MRSA patients, no significant impact was seen in the reduction of HA-MRSA infections.

Objective: Active surveillance for MRSA was instituted as an additional intervention in November 2007 at SGH in phases in an attempt to further reduce our HA-MRSA infection rates.  The program is established hospital-wide by Nov 2008.

Methods: The active MRSA surveillance program was introduced in phases to all the wards from November 2007, with support from the management and heads of department. High risk patient groups fulfilling a set of criteria were screened for MRSA nasal colonization – past history of MRSA, history of hospitalization (local or overseas) in past year, history of stay in a long term care facility in past year, end stage renal failure patients on dialysis.  Nasal swabs were processed using the enrichment broth method and chromogenic agar method. Patients who were identified as MRSA positive were isolated or cohorted together as there are inadequate isolation facilities.  An orange sticker was placed at the patient’s case notes and patient’s name slot at the door entrance to alert health care workers on need for Contact Precautions when managing the patient.   These MRSA patients were given Chlorhexidine gluconate 4% bath and shampoo over 5 days to reduce the bioburden. A series of interactive education and video screening were shown to all health care workers to promote the awareness and importance of the program.  All wards were kept regularly informed of their own HA-MRSA infection rates.

Results: As expected, there was an increase in number of MRSA colonizers detected upon admission or transfer.  However, the number of HA-MRSA infections showed a reduction from 31 to 10 cases per month. In addition, we noted an improvement in hand hygiene compliance rate from 46.5% to 68.1% since implementation of the program.  The HA-MRSA infection rates saw a steady decline from 0.62 in 2007 to 0.58 in 2008 and then 0.46 per 1000 patient days in 2009 (Jan-Sep).

Conclusions: Despite the limited number of isolation facilities, the approach of conducting an active surveillance for MRSA for high risk patients upon admission or transfer has helped towards facilitating early detection of MRSA patients.  This aided in our prompt employment of effective infection control measures which proved to effectively reduce HA-MRSA infections.