Figure 1. Emergency Medical Services (EMS) regions in Tennessee, USA: 1) Northeast; 2) East; 3) Southeast; 4) Upper Cumberland; 5) Mid-Cumberland; 6) South Central; 7) West; and 8) Memphis-Delta. The 8 EMS regions represent the referral patterns for EMS services and hospitals and for coordination for emergency preparedness activities. The Tennessee Department of Health uses EMS regions to aggregate multidrug-resistant organisms surveillance data. Stars indicate metropolitan areas within EMS regions.