Universal Screening at Hospital Admission to Reduce Nosocomial Methicillin-resistant Staphylococcus aureus (MRSA) Infection?

A study reported in the March 12 issue of the Journal of the American Medical Association (JAMA. 2008;299:1149-1157, 1190-1192.) concluded that universal screening on hospital admission for methicillin-resistant Staphylococcus aureus (MRSA) infection may not reduce the rate of hospital-acquired infections in surgical patients. Most surgical specialties have a rate of MRSA bacteremia between 0.5 and 1.5 cases per 10,000 patient-days, and intervention may reduce the rate of systemic and surgical site infection. Experts and policy makers have recommended universal admission screening as a means to control MRSA infection, but no large clinical trial has evaluated the efficacy of such screening.

The study discussed in here was designed to evaluate the effect of a MRSA early detection strategy on nosocomial MRSA infections in a cohort of surgical patients at a large Swiss teaching hospital with endemic MRSA. Thw study was a randomized, crossover clinical trial involving all surgical specialties within 1 hospital to examine the impact of an admission screening intervention on MRSA incidence, acquisition, and surgical site infection when standard infection control protocols are in place. The hospital had 365 beds with 13,280 admissions in the year of the study.

During the intervention periods, 93 patients (1.11 per 1000 patient-days) developed nosocomial MRSA infection, as did 76 patients during the control periods (0.91 per 1000 patient-days; adjusted incidence rate ratio, 1.20; 95% confidence interval, 0.85 - 1.69; P = .29). Rates of MRSA surgical site infection and nosocomial MRSA acquisition did not change significantly. In the intervention wards, 53 (57%) of 93 infected patients were MRSA-free on admission and developed MRSA infection during hospitalization.

The authors concluded that given low incidence of MRSA carrier rate at their hospital on admission, universal screening did not reduce MRSA acquisition, and this may also be because of screening results not being available until after emergency surgery for 31% of patients who screened positive.