Community-onset (CO) methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) prevalence is a significant predictor of hospital-onset rates, and >80% of MRSA BSIs are CO-MRSA. We describe geographic distribution and characteristics of hospitals with higher CO MRSA BSI rates.
Data on CO MRSA BSIs (positive blood cultures collected in outpatient locations or ≤3 days after admission) were obtained from general hospitals reporting MRSA BSI events facility-wide for all of in 2015 to the National Healthcare Safety Network (NHSN). Hospital characteristics were obtained from NHSN and the American Hospital Association 2015 Annual Survey. Using hospital admissions as a measure of hospital volume, we calculated unadjusted pooled CO MRSA rates (events/1000 admissions) by census division and performed a negative binomial regression for adjusted rate ratios (aRRs) and 95% confidence intervals (CI) for facility characteristics associated with higher facility-level CO MRSA BSI rates.
Of the 3,401 general hospitals that reported for 12 months, complete data on hospital-characteristics were available from 2,766 (85%). These hospitals reported 69,546 CO MRSA BSI events in 2015. The number of unadjusted CO MRSA BSI events/1000 admissions varied across census divisions with the highest in the Mountain Division (3.71) and the lowest in the West North Central Division (1.57). Census division, size >500 beds (aRR: 1.24, 95% CI 1.07–1.44), location in a micropolitan (containing at least one urban cluster >10,000 but <50,000 people) vs metropolitan area (aRR: 1.30, 95% CI 1.17–1.44), lower volume of surgical operations (aRR: 0.99 per 1000 operations, 95% CI 0.99–0.99), and public hospital status (aRR: 1.29, 95% CI 1.15–1.43) were all associated with higher CO MRSA BSI rates. Teaching hospital status (p=0.48) and provision of chemotherapy (p=0.36) and transplant services (p=0.51) were not associated with higher CO MRSA BSI rates.
After controlling for several hospital characteristics, significant differences in CO MRSA BSI rates persisted among census divisions. Further understanding causes of variation in CO MRSA rates, such as the role of community characteristics in determining regional differences, could provide insight into CO MRSA BSI prevention strategies.
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