A statewide collaborative to reduce methicillin-resistant Staphylococcus aureus bacteremias in New Mexico

Background: Infection control guidelines recommend multiple interventions to reduce MRSA infections , including active surveillance testing for colonization.  In New Mexico laboratories, MRSA rose from 5% to 55-60% of all Staphylococcus aureus isolates from 1989 to 2006. Infection preventionists and medical practitioners asked for support to control this problem.

Objective: This quasi-experimental study investigated the effect of an infection control collaborative on the rates of MRSA bacteremia in a cohort of urban and rural hospitals and the use of a “bundle” of interventions. Our goal was to decrease the rate of hospital-onset MRSA bacteremias by 40%.

Methods: A steering committee representing key healthcare organizations in New Mexico recruited the collaborative cohort, who agreed to submit data on outcomes and interventions, and participate in learning sessions, conference calls and site visits.
During the intervention year, the committee provided three learning sessions, an outcomes congress, conference calls, site visits, and on-site continuing medical education lectures. Guidelines and key literature were disseminated, and participants shared policies, order sets, signage, and educational tools.
Results: We recruited 12 acute care hospitals and 1 long-term acute care hospital, ranging in size from 22 to 623 licensed beds, representing 60% of New Mexico acute care beds. Hospital-onset bacteremia was defined as occurring more than 48 hours after admission, healthcare-associated as present on admission within 30 days of discharge from that facility, and community-onset as all other bacteremias.
Participants reported 44 hospital-onset, 18 healthcare-associated, and   122 community- onset MRSA bacteremias in the baseline year, yielding a hospital-onset rate of   0.79 per 10,000 patient- days. By the second 6 month period of the collaborative, the numbers of hospital-onset bacteremias fell to 10, with a rate of 0.41, representing a 48% decline in the aggregate rate. Rates of healthcare-associated and community-onset bacteremias were unchanged.
Statistical analysis using a generalized linear and mixed model with a Poisson distribution, with  individual hospitals treated as a random effect, failed to demonstrate statistical significance of this result.
At baseline, active surveillance testing was performed on 241 beds in 4 hospitals, which increased to 369 beds in 7 hospitals by July 2009. 10 hospitals completed a final survey detailing their  methods and barriers to implementation of the bundle.
Conclusions: We demonstrated the flexibility of the collaborative model in engaging a range of hospital sizes and types across a large rural state to produce  measurable improvement in one year of intervention. Health information exchange and expansion of data collection outside acute care are needed to improve our understanding of the epidemiology of MRSA bacteremia.