588. The Association Between Contact Precautions for Methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) Colonization and MRSA Bloodstream Infection (BSI) Rates in Los Angeles County Hospitals: Results of a Countywide Survey

Abstract Background Contact precautions are frequently used to prevent in-facility transmission of MRSA, but their efficacy has been questioned. We hypothesized that contact precautions use would not correlate with MRSA bloodstream infection (BSI) rates in LA County hospitals. Methods The LA County Department of Public Health conducted a survey of LA County acute care hospitals’ use of contact precautions for MRSA colonization, history of MRSA infection/colonization, and active MRSA infection with or without uncontained purulence. We modeled National Healthcare Safety Network (NHSN) reported healthcare-associated MRSA BSI rates from 2022-23 via a negative binomial multivariable regression model. We controlled for hospital type (general acute care hospitals vs. long-term acute care hospitals (LTACHs)), number of intensive care unit (ICU) beds, and MRSA BSI admission prevalence rates. Results Of the 82 acute care hospitals in LA County, 69 completed the survey (84% response rate). MRSA contact precaution use was stratified into three groups: Least strict (no contact precautions or contact precautions only for active infection with uncontained purulence, 24% of hospitals), intermediate (contact precautions for any active infection, 32% of hospitals), and most strict (contact precautions for &amp;gt;2 reasons, 44% of hospitals). We found higher MRSA BSI in LTACHs vs. hospitals (Incidence rate ratio [IRR] 3.50, 95% CL 1.80-6.80, p = 0.0002), but no relationship with ICU beds (IRR 1.00, 95% CL 0.99-1.01, p = 0.15), MRSA BSI admission prevalence rates (IRR = 4.40, 95% CL 0.30-63.10, p = 0.27), or contact precaution use (IRR 0.80, 95% CL 0.50-1.30, p = 0.29 for the least strict group; IRR 1.40, 95% CL 0.89-2.20, p = 0.14 for the intermediate group, both in comparison to the most strict group). Conclusion Our survey of hospitals across LA County, which has a population of ∼10 million, found no significant association between stringency of MRSA contact precaution use and healthcare-associated MRSA BSI rate. Our findings support other data that fail to find clinical benefit to contact precautions for MRSA colonization/infection. Considering potential downsides of contact precautions for MRSA, the assumption that MRSA requires contact precautions may need to be reconsidered. Disclosures Loren G. Miller, MD MPH, Armata: Grant/Research Support|Contrafect: Grant/Research Support|GSK: Grant/Research Support|Merck: Grant/Research Support|Paratek: Grant/Research Support