Drug Resistance Index

A novel way to track antibiotic resistance applied to two common infections underscores need to develop drugs against emerging pathogens

The Drug Resistance Index (DRI) is a composite measure that combines the ability of antibiotics to treat infections with the extent of their use in clinical practice. Described by Science Magazine as a Dow Jones for Drug Resistance, the DRI provides an aggregate trend measure of the effectiveness of available drugs, akin to the way composite economic indices are used to track movement sin consumer prices and stock market values.

We illustrate the DRI using national and regional U.S. data for two of the most common causes for antibiotic use: urinary tract infections (UTIs) and skin and soft tissue infections (SSTIs), each accounting for over 8 million office visits in a calendar year. The index for UTIs shows the number of infections facing treatment difficulties has been increasing since the mid-2000s due to the rapid spread of resistance among Gram-negative organisms (such as E. coli) that are the primary cause of UTIs. In contrast, our ability to treat SSTIs (usually caused by Gram-positive organisms such as S. aureus) declined rapidly in the early 2000s, but has improved since, likely due to the availability of new, more powerful drugs. The divergence underscore the need for developing new antibiotics geared towards the emerging threat of drug-resistant Gram-negative organisms.

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