Antibiotics on the shelf today are increasingly losing their potency against resistant microbes or superbugs like the potentially lethal methicillin-resistant Staphylococcus aureus, or MRSA.

Extending the Cure researchers published an analysis this week that questions the conventional wisdom regarding antibiotic dosing practices and suggests rethinking the guidelines to minimize the growing public health crisis posed by antibiotic resistance. Ramanan Laxminarayan, director of Extending the Cure, and his colleagues, used mathematical models to study antibiotic treatment guidelines, the regimens physicians follow for the standard dose and duration of antibiotic treatment for common infections.

While antibiotic dosing regimens have typically been designed to cure bacterial infections, rarely have these guidelines taken antibiotic resistance into account.  All antibiotic use contributes to the development of antibiotic resistance, and the new research suggests dosing guidelines could be optimized to both treat infections and limit the spread of resistant microbes. The analysis, published January 11 in the online scientific journal PLoS ONE, indicates that in many cases, a shorter regimen of antibiotic treatment could work just as well as a longer course yet still reduce the risk of resistance.

Dosing strategies for antibiotics are not set in stone.  For example, many physicians have switched from the traditional 10-day course of antibiotics and now effectively prescribe a three-day regimen to treat otitis media, or middle ear infections. In some cases, the authors argue, shorter dosing regimens like this one could limit the selection pressure for resistant bacteria and thus reduce the threat of resistance.

Extending the Cure, a project of the Center for Disease Dynamics, Economics & Policy sponsored by the Robert Wood Johnson Foundation s Pioneer Portfolio, is working to change how we think about antibiotics, a resource that can be depleted with overuse. This study suggests that shorter treatment regimens, in some cases, may help us preserve the power of the antibiotics we still have left.

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