MRSA Proportion Across European Union Countries: Associations with Antimicrobial Consumption, Livestock Density, and Pesticide Use

Background/Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) remains an important One Health challenge, yet its combined human, animal, and environmental correlates remain incompletely understood. This study examined associations of human antibiotic consumption, veterinary antimicrobial sales, pig and poultry density, and pesticide use with the proportion of methicillin resistance among invasive S. aureus isolates (MRSA proportion) across 27 European Union countries. Methods: Country-level panel data (2013–2023, 297 country-year observations) were analyzed using two-way fixed-effects regression with Driscoll–Kraay standard errors, a Spatial Lag of X (SLX) model, and Global/Local Moran’s I statistics. Results: Human antibiotic consumption showed the most consistent positive association with MRSA (β = 0.523, p < 0.001), remaining significant in the SLX model, across alternative spatial weights, and in models for proportional outcomes, as did the local association of pig density. Pesticide use showed a negative within-country association (β = −0.189, p = 0.015) that was not retained in fractional logit models and, in the primary SLX model, a positive spillover association (θ = 1.097, p < 0.001) that was sensitive to the spatial-weight specification. Veterinary antimicrobial sales showed a positive total effect across all spatial weight specifications, whereas the poultry density spillover was not robust. MRSA exhibited persistent positive spatial clustering (Moran’s I = 0.481–0.558; all p = 0.001), with High–High clusters in southeastern and Low–Low clusters in northern Europe. Conclusions: At the country level, human antibiotic consumption was most consistently associated with MRSA proportion, whereas pesticide- and poultry-related spillover associations were specification-dependent. These ecological associations should be regarded as hypothesis-generating; nevertheless, they support integrated, cross-border One Health surveillance of antimicrobial resistance.