Change in methicillin-resistant Staphylococcus aureus testing in the Intensive Care Unit as an antimicrobial stewardship initiative

BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) associated infections are a cause of morbidity/mortality in the Intensive Care Unit (ICU). Vancomycin is an option for treatment but is not without its own risks. PurposeTo institute a testing change to decrease time between ordering of MRSA tests and availability of results in patients admitted to the adult ICU. ProceduresA MRSA testing change was implemented at two adult (i.e., tertiary and community) ICUs located in a U.S. Midwestern health system. The change was implemented in 2018 and included the switch from culture to polymerase chain reaction (PCR) in ICU admitted patients. Study data were collected from 2016-2020 and a Bayesian quantile regression model was fit to examine median level change in time to results and to calculate a counterfactual estimate. Main FindingsDuring the 58-month period, 71% of 19,975 patients seen at the two ICUs received MRSA testing. In the pre-change period, 91% and 99% of patients at the tertiary and community hospitals received testing via culture, respectively. Culture was used 1% and [~]0% of the time at the hospitals in the post-change period. The counterfactual estimated 36 (95% CrI: 35, 37) and 32 fewer hours (95% CrI: 31, 33) until results were available at the tertiary and community hospital, respectively. ConclusionsStudy revealed MRSA results were available in less time at both facilities after testing change. This information can aid anti-microbial stewardship via possibly delaying initiation and/or quicker de-escalation of therapy when results are known.