Simple Measurement Could Bring Abandoned Antibiotics Back to the Clinic

Scientists at Duke University have developed a simple method for fine-tuning antibiotic dosing protocols that could allow use of antibiotics that have been all but abandoned. Computer models and preliminary laboratory work suggest that by determining a pathogen’s recovery time after exposure to an antibiotic, a dosing regimen can be established that allows clearing of what at present are considered resistant strains.

The computer program models resistance to one of the most common classes of antibiotics, β-lactams. Use of these highly effective antibiotics has declined because of the increased occurrence of extended spectrum β-lactamase (ESBL) producing pathogens. The β-lactamase secreted by these pathogens hydrolyzes β-lactams, leaving the antibiotic ineffective. Currently, when ESBL-producing pathogens are detected, stronger antibiotics are used that are more expensive and often have harsher side effects.

The model developed by Hannah Meredith suggests that this is an unnecessary practice. Moderate ESBL-producers depend on a high population density in order to produce sufficient β-lactamase to inactivate the antibiotic. In these populations an initial dose of the antibiotic will reduce the population size to an extent that makes the ESBL-producing pathogens susceptible to β-lactams until their population size recovers. Meredith has termed the window of time it takes a population to return to its initial density recovery time. Based on the recovery time her algorithm can calculate the optimal antibiotic concentration, dose number, and treatment period length. By experimentally determining the recovery times for different pathogen-antibody pairs, a database can be created that could bring many abandoned antibiotics back into the clinic. Meredith is currently working to create such a database and preliminary results have confirmed many of her model’s predictions.

Source: Science Daily