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Background Staphylococcus aureus (SA) is a leading cause of hospital-acquired infection, including bloodstream infection (BSI), in NICUs. In this study, we evaluated the effect of screening and decolonization of MSSA-colonized babies with mupirocin on the rate of MSSA infection. Patients and Methods. Study design: Sequential time series. Pre-intervention period, January 2015–March 2017; wash out period, April 2017; intervention period, May 2017–March 2018. Population: Neonates admitted to a Level IV NICU with anticipated stay of greater than 2 days. Intervention: A single swab of the nares, umbilicus & groin was sent weekly for SA surveillance culture. MSSA-colonized neonates were decolonized with mupirocin application to nares, umbilicus and abraded skin twice daily for 5 days. Outcome measures: Comparison of rates of MSSA infections during pre- and post-intervention periods. Infections included BSI and skin/wound infections, excluding patients with MSSA from only eye or respiratory specimens. Comparators: Change in rates of Gram-negative and MRSA BSI. Change in rates of MSSA BSI in an affiliated NICU with the same medical staff but no intervention. Results MSSA BSI decreased from 0.37 per 1,000 hospital days (n = 15) to 0.00 (n = 0), P = 0.0092. All MSSA infections decreased from 0.62 (n = 25) to 0.11 (n = 2), P = 0.0078. Of 694 eligible neonates, 98.8% were screened at least once for MSSA colonization, which was detected in 92 (13.4%) infants. Median weekly prevalence of colonization was 6.7%. Median length of stay of neonates after initial detection of colonization was 30 days. Of colonized neonates, 92% received mupirocin treatment, with a median of 1 course of mupirocin treatment per patient (range, 1–7 courses). Of 54 isolates tested, all were mupirocin-susceptible. In contrast, there was no significant change in the rates of either MRSA (P = 0.71) or Gram-negative (P = 0.45) BSIs. In the comparison NICU, there was no significant change in rate of MSSA BSIs (P = 0.34). Conclusion Despite a substantial burden of MSSA-colonized neonates, the intervention was associated with elimination of MSSA BSI and an 82% reduction in rate of MSSA infections. A potential confounding factor was the occurrence of a cluster of mupirocin-resistant MRSA during the intervention period with the associated intensified infection prevention measures. Disclosures All authors: No reported disclosures.

Background Staphylococcus aureus (SA) is a leading cause of nosocomial infection in NICUs. Colonization is a prerequisite for most SA infections. Previously recognized risk factors for colonization include the length of stay (LOS), multiple gestation, low birth weight, Caesarean delivery and multibed location. The objective of this study was to determine risk factors for MRSA colonization in a Level IV NICU independent of LOS and gestational age (GA) in the context of a circulating MRSA clone. Methods Weekly MRSA colonization cultures were performed from April 2017 through March 2018. Case–control study. Cases: Infants with newly acquired MRSA colonization and at least one previous negative culture. Controls: Infants with negative surveillance cultures, matched 1:1 with cases by GA and LOS. Factors compared: (a) neonatal demographics; (b) maternal factors; (c) neonatal factors since admission including antimicrobial therapy; (d) neonatal factors during the week prior to MRSA acquisition, including bed location, number of location changes, presence of central line, respiratory support, NICU census, ATP surface bioburden testing pass rate, MRSA colonization pressure. Results 50 case infants were matched with controls. Forty-five of the 50 isolates were mupirocin-resistant and related by pulse-field gel electrophoresis On matched univariable analysis, the following were significantly associated with a risk for MRSA acquisition: (1) Bed location in the acute area (P = 0.03), (2) The requirement of any level of respiratory support during the week prior to MRSA detection (P = 0.04), (3) Higher ATP pass rate during the week of and week prior (P = 0.01), (4) Higher MRSA colonization pressure during the prior week (P = 0.002), (5) Not having a hearing test during the time between the previous negative culture and MRSA acquisition (P = 0.01). A multivariable conditional logistic regression model (that excluded ATP pass rate) found that only colonization pressure was associated with acquisition of MRSA colonization. Conclusion Independent of LOS and GA, MRSA colonization pressure, ATP pass rate and higher patient acuity, reflected by location within the acute area and requiring respiratory support, are significantly associated with MRSA acquisition in the NICU; only colonization pressure remained associated in a multivariable model. Disclosures All authors: No reported disclosures.