2146. Impact of MRSA colonization pressure on MRSA acquisition and MRSA infection in pediatric intensive care unit

Abstract

Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA) colonization pressure (CP) is a useful indicator for measuring the extent of MRSA reservoir in healthcare settings. The purpose of this study is to determine the MRSA colonization rate and invasive MRSA infection rate in severely ill pediatric patients requiring pediatric intensive care unit (PICU) stay, and to evaluate the association between MRSA CP and MRSA acquisition/invasive infection. Methods From January 2016 to December 2020, pediatric patients admitted to 2 PICUs with a total of 25 beds were retrospectively analyzed. Routine nasal and/or endotracheal cultures were performed on MRSA at the time of PCIU admission and thereafter, every week. MRSA CP was defined as the ratio of the monthly MRSA positive number of patients to 100 patient days. Among MRSA colonizers, MRSA obtained after 2 days of PICU admission was defined as an acquired colonizer, and imported colonizer was defined when it was confirmed as an MRSA colonizer at the time or within 2 days of entry. When MRSA was cultured in a normally sterile body fluids, it was defined as an invasive MRSA infection. Results Of the total 6,907 patients admitted to the PICUs during this study period, 8.4% (487/6,907) were MRSA colonizers; 30% (139/487) were acquired colonizers, and invasive MRSA infections occurred in 3.3% (16/487). During the stay in the PICUs, the MRSA acquisition rate was 4.1%. A total of 22 invasive MRSA infections occurred during this study period, with an incidence rate of 3.1/1,000 patient days, of which 72.7% (n=16) occurred to the patients with MRSA colonization. Invasive MRSA infection occurred in 2.4% (8/348) of imported colonizers, and 5.2% (8/139) of acquired colonizers (p=0.108). The median duration from the time of colonization to invasive infection was 24 days(IQR; 2.25-49.75). Although MRSA CP was not correlated with the incidence of invasive MRSA infection (p=0.101), MRSA CP itself affected MRSA acquisition in PICU (p< 0.001). Conclusion MRSA CP influenced the new acquisition of MRSA during PICU stay, and newly acquired colonizers are more likely to experience invasive MRSA infection. Continuous multi-faceted efforts to minimize MRSA CP can provide opportunities for reducing MRSA colonization and infections rates in PICU settings. Disclosures All Authors: No reported disclosures.