The role of infection control in preventing MRSA bacteraemia

Over the past decade, a number of interventions have been proposed to prevent the development of nosocomial infections caused by methicillin-resistant strains of Staphylococcus aureus (MRSA), but their comparative effectiveness has not been studied before.

In order to clarify the above question, S.S. Huang et al. (United States), a retrospective study of 4 large-scale infection control interventions was performed using the design of an interrupted time series to assess their impact on the incidence of bacteremia caused by MRSA in a hospital 800 beds with 8 intensive care units (ICU). The interventions were carried out one by one over limited periods of 9 years and included:

Deviations from monthly data on the prevalence of MRSA bacteremia and its share in the structure of infections from predicted values were estimated using segmented regression analysis. Bacteremia caused by methicillin-sensitive strains of S. aureus was the control group.

According to the results, only routine cultural studies in patients with subsequent isolation of colonized individuals led to a significant reduction in the incidence of bacteremia caused by MRSA, both in ICU and in other departments. After 16 months of using this intervention, the incidence rate of bacteremia caused by MRSA decreased by 75% in ICU (P = 0.007) and by 40% in the services of another profile (p = 0.008) , which led to an overall decrease in this indicator in hospital by 67% (p = 0.002). At the same time, the incidence of bacteremia caused by methicillin-sensitive strains of S.aureus remained unchanged throughout the study period. The introduction of other measures was not accompanied by a statistically significant change in the incidence of bacteremia caused by MRSA.

Thus, systematic screening for the identification of colonization by MRSA in ICU patients was accompanied by a significant reduction in the incidence of bacteremia caused by this microorganism both in ICU and in medical establishment as a whole, while the other types of interventions studied did not have a similar effect.