Epidemiology of methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus in a rural state

BACKGROUND. Most data on methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) isolates come from large tertiary care centers. Infection control personnel need to understand the epidemiology of MRSA and VRE across the continuum of care, including small rural hospitals, to develop effective control strategies. OBJECTIVE. To describe the epidemiology of MRSA and VRE in Iowa. SETTING. Fifteen hospitals in Iowa. METHODS Between July 1998 and June 2001, a total of 1,968 S. aureus isolates and 1,845 Enterococcus isolates from patients infected with these pathogens were examined. Multivariate models were developed to evaluate patient and institutional risk factors for MRSA infection and VRE infection. RESULTS. The proportion of S. aureus isolates resistant to methicillin was 31%, and the proportion of Enterococcus isolates resistant to vancomycin was 6%. Independent risk factors for MRSA infection included residence in a long-term care facility, age of more than 60 years, hospitalization in a hospital with less than 200 short-term care beds, and acquiring the infection in the hospital. Independent risk factors for VRE infection included use of a central venous catheter, residence in a long-term care facility, acquisition of infection in the hospital, and hospitalization in a hospital with more than 200 short-term care beds. CONCLUSIONS. In Iowa, the epidemiology of MRSA differ from those of VRE. MRSA has become established in small rural hospitals. Effective MRSA control strategies may require inclusion of all hospitals in a state or region.