Impact of a Surveillance Screening Program on Rates of Methicillin-Resistant Staphylococcus Aureus Infections with a Comparison of Surgical Versus Nonsurgical Patients

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of health care–associated infection. The overall effectiveness of surveillance screening programs is not well established. A retrospective cohort study was performed to evaluate the impact of a surveillance screening program on the rates of health care–associated MRSA infection (HA-MRSA-I) at a single institution. A subset of surgical patients was analyzed separately. Multivariate regression techniques were used to identify predictors of the desired outcomes. The overall MRSA infection rate was 1.3% in the before cohort and 3.2% in the after cohort. After excluding patients with a history of MRSA infection or MRSA colonization, HA-MRSA-I decreased from 1.2% to 0.87%. There was a similar overall increase in the surgical group, 1.4% to 2.3%, and decrease in HA-MRSA-I, 1.4% to 1.0% (P < 0.001). For all patients, surgery, African American race, and increased length of stay conferred an increased likelihood of HA-MRSA-I. Females and patients in the after cohort had a lower risk of HA-MRSA-I (P < 0.01). In the after cohort, the results were similar, with surgery, African American race, and length of stay associated with an increased risk, and female sex associated with a decreased risk (P < 0.05). African American race and increased age had a higher likelihood of screening positive for MRSA colonization, while the surgical group, females, and Hispanic patients were less likely (P < 0.05). HA-MRSA-I was associated with a higher mortality among all patients (P < 0.001). Mortality rates were similar with HA-MRSA-I for all patients (10.8% vs 9.5%, P = 0.55) and in the surgical group (8.3% vs 6.8%, P = 0.58). In conclusion, surveillance programs may be effective in decreasing HA-MRSA-I. Further studies are needed to determine how to reduce transmission, particularly among African Americans and those with increased lengths of stay.