Impact of a methicillin-resistant Staphylococcus aureus active surveillance program on contact precaution utilization in a surgical intensive care unit.

OBJECTIVE

To determine the impact of an active surveillance for methicillin-resistant Staphylococcus aureus (MRSA) on contact precaution utilization, as measured by additional number of contact precaution days attributable to the active surveillance program.

DESIGN

Prospective cohort study.

SETTING

Twenty-four-bed surgical intensive care unit (ICU).

PATIENTS

All patients admitted to the surgical ICU.

INTERVENTIONS

Nasal cultures for MRSA were performed at admission to a surgical ICU for 19 months. Patients admitted>48 hrs also received weekly and discharge nasal cultures.

MEASUREMENTS AND MAIN RESULTS

Clinical data, including start date and initial indication for contact precautions, were prospectively collected. Of 1,893 admissions, 253 (13%) were found to be MRSA-positive during their ICU stay. One hundred forty-six (58%) were identified by nasal culture alone. Compared with the first 10 months of study, the prevalence of MRSA on admission to the ICU during the last 9 months of the study period significantly increased (7.2% vs. 11.4%, p<.001). Acquisition of MRSA by noncolonized patients remained constant between the first 10 months and last 9 months of study (7.0 vs. 5.5 cases per 1000 patient days, p=.29). Two hundred fourteen (6%) of 3461 total contact precaution days in the ICU were attributable to MRSA active surveillance. In sensitivity analyses, the implementation of rapid, same-day results for MRSA active surveillance would increase contact precaution days by 15% compared with no surveillance. If the total number of vancomycin-resistant enterococci patients in the ICU were reduced by 50%, the contact precaution days attributable to active surveillance would increase to 9%.

CONCLUSIONS

MRSA active surveillance increased total contact precaution days in this ICU by 6% yet detected 58% of MRSA cases that would have been otherwise missed. Despite an increasing prevalence of MRSA on admission to the ICU, the acquisition rate has remained constant.