Down To Earth– January 21, 2020. A drug resistance index (DRI) — developed by researchers from the Center for Disease Dynamics, Economics & Policy (CDDEP), Washington and Rollins School of Public Health, Emory University, Georgia — was used to track global trends in effectiveness of antibiotic therapy in 41 countries in 2018. The result showed that high-income countries had the lowest DRIs and low-income and middle income countries had high DRIs.