The Demise of MRSA at an Academic Medical Center

Background:   Despite the emergence of other important nosocomial pathogens, MRSA continues to dominate media reports and some states have mandated active surveillance cultures for MRSA on patients admitted to hospitals. Some proponents of active surveillance claim that no other effective measures exist to control this pathogen. Previous analyses by our group suggested that MRSA could be reduced in the critical care setting without active surveillance cultures; however, the magnitude of success and the sustainability of such an approach were uncertain.
Objective: To describe trends in device-related MRSA infections in the adult critical care setting.
Methods: Beginning in 2004, a series of non-pathogen specific initiatives was implemented to reduce healthcare associated infections (HAIs) in our 820-bed, urban, teaching hospital. This included an increasingly aggressive hand hygiene program, a central line bundle, a ventilator bundle, and chlorhexidine bathing of all adult ICU patients, and a recommendation for bare below the elbows, along with compliance monitoring and feedback via unit-specific posters. Active surveillance cultures were not performed. Rates of central line associated bloodstream infections (CLABSI), catheter associated urinary tract infections (UTI) and ventilator associated pneumonia (VAP) due to MRSA were determined via concurrent surveillance by trained infection control practitioners utilizing CDC definitions in a 16-bed medical ICU, an 18-bed surgical ICU, and a 14-bed neuroscience ICU.
Results:

Rates of infections are shown below:

	Rate denominator	2003	2004	2005	2006	2007	2008	2009
CLABSI	1,000 line days	1.44	1.18	1.42	0.34	0.23	0.42	0.13
UTI	1,000 catheter days	0.24	0.08	0.00	0.30	0.15	0.15	0.09
VAP	1,000 ventilator days	4.15	1.27	0.75	0.61	0.48	0.24	0.33
TOTAL	1,000 patient days	2.86	1.55	1.16	0.76	0.49	0.47	0.28

Over the 7 year period, we observed a 91% reduction in MRSA CLABSI, 62% reduction in MRSA UTI and a 92% reduction in MRSA VAP. The total number of MRSA infections in the 3 ICUs fell from 38 in 2003 to 5 in 2009 (annualized from the first 3 quarters of 2009). For the first time ever, in a calendar quarter (Q3 2009), there were no MRSA device associated HAIs in any of our 8 adult, pediatric and neonatal ICUs (136 beds, 8,546 patient days).

Conclusions:   Our data demonstrate that significant and sustained reductions in MRSA device-related infections can be achieved without resorting to active surveillance cultures. We recommend interventions that focus broadly on reducing all HAIs via compliance with optimal infection control practices rather than a resource intensive strategy of questionable effectiveness associated with harm, and targeted against a single pathogen that accounts for a small fraction of HAIs.