Decreasing Methicillin-Resistant Staphylococcus aureus Infection in the Setting Of Active Surveillance

Background: Despite previous attempts to decrease acquisition of MRSA during the hospitalization, the number of acquisitions remained significant in the medical/surgical inpatient wards of ALMVA, a 268 bed hospital.  This is an QI intervention project that evaluates multiple interventions on MRSA acquisition rate at ALMVA during February 2010 to May 2010, compared to the baseline rate during the previous four months.

Objective: To decrease MRSA acquisition rate on ALMVA inpatient medicine units over a 4 month period (February to May 2010) by improving compliance with hand hygiene (HH), isolation precautions and environmental cleanliness.

Methods:   This was an ambidirectional evaluation of intervention efficacy, prompted by a VA mandate for active surveillance (admission/transfer/discharge) of MRSA colonization with PCR. The participants were all of the inpatients in the VA inpatient medicine wards (Medicine: 5A, 6B, Surgery: 4S and MICU) during the months in study (from October 2009 to May 2010).  ALMVA is a 268 bed hospital, which averages about 36000 patient days a year in the wards under surveillance.  All patients were screened according to the mandate.   A bundled approach to decrease MRSA transmission rates was implemented, based on the guidelines to prevent MRSA infection and infection control literature.  Compliance with hand hygiene and isolation precautions was monitored by blinded reviewers from Voluntary Services and weekly rounds with a multidisciplinary team, with immediate audit feedback, were performed.

Primary outcome measure was the number of MRSA acquisitions per 1000 pt days in each individual unit.  In addition, we monitored monthly rate (%) of hand hygiene, contact isolation compliance and optimal environmental cleaning.

Results:

The mean MRSA transmission rate decreased from 2.8/1000 pt days to 0.4/1000 pt days.  Statistical analysis between pre and post intervention MRSA transmission rates was significant by T-test (p<0.01).  In addition, the percentage of acceptable environmentally cleaned rooms increased from 20% pre-intervention to 60% during intervention.

Conclusions: MRSA acquisition can be decreased in the setting of active screening by using a multi-level approach to the problem, including enhanced surveillance of hand hygiene compliance, isolation and environmental cleanliness.  In addition, by presuming a 23% risk of development of a serious invasive MRSA infection within 12 months after MRSA acquisition (Datta, et al, CID 2008) and a direct cost of $7481 for inpatient MRSA infections (Lodise, et al, Pharmacotherapy 2007), we predicted an annual cost savings of over $147,000 from avoidance of 19.7 MRSA infections per year.