Andreatos N, et al. - The association of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection with socioeconomic factors and antibiotic prescriptions was investigated at the county level. Researchers noted a strong association of MRSA bloodstream infection rates with county-level antibiotic use and socioeconomic factors. If the causality of these associations is confirmed, antimicrobial stewardship programs that extend outside acute healthcare facilities may help in reducing the spread of MRSA.

Methods

• Researchers assessed MRSA bloodstream infection rates from the Medicare Hospital Compare database.
• From the U.S. Census Bureau and the Medicare Part D database, they obtained data on socioeconomic factors and antibiotic prescriptions, respectively.

Results

• Multivariate analysis revealed a powerful positive association of antibiotic prescriptions with MRSA bloodstream infection rates [Coefficient (Coeff): 0.432, 95% Confidence Interval (CI): 0.389, 0.474, P < 0.001], which was largely attributable to lincosamides (Coeff: 0.257, 95%CI: 0.177, 0.336, P < 0.001), glycopeptides (Coeff: 0.223, 95%CI: 0.175, 0.272, P < 0.001), and sulfonamides (Coeff: 0.166, 95%CI: 0.082, 0.249, P < 0.001).
• A secondary positive impact was noted to be exerted by sociodemographic factors, such as poverty (Coeff: 0.094, 95% CI: 0.034, 0.155, P=0.002) on MRSA bloodstream infection.
• Conversely, MRSA incidence rates were noted to have negative association with college education (Coeff: -0.037, 95%CI: -0.068, -0.005, P=0.024), a larger median room number per house (Coeff: -0.107, 95%CI: -0.134, -0.081, P<0.001), and an income above the poverty line (100%P < 0.001).
• Incorporation of socioeconomic data and antibiotic prescription rates, in a multivariate model, predicted 39.1% of the observed variation in MRSA bloodstream infection rates (P_model < 0.001).