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Mathematical Biology Seminar

May 4, 2022 - 11:00am

Samantha Erwin, PhD

Data Scientist at Pacific Northwest National Laboratory

When: Tomorrow (Wednesday, May 4th at 11am).


Title: Mathematical model of the effects of antibiotics on antimicrobial susceptibility of enteric bacteria

Abstract: Antibiotics administered systemically can cause emergence and dissemination of antimicrobial resistance among enteric bacteria. In order to develop rational, research-based recommendations for food animal veterinarians we need to understand how to maximize antibiotic efficacy while minimizing risk of antimicrobial resistance. Our objective is to evaluate the effect of two approved dose regimens of enrofloxacin (a single high dose or three low doses) in cattle on enteric bacteria. For that purpose, we developed an ordinary differential equation model for the antibiotic concentrations in plasma and colon and bacteria populations in the colon. The model was fitted to individual animal data of antibiotic concentrations in the plasma and colon obtained using an ultrafiltration probe. E. coli counts in feces and the minimum inhibitory concentrations were measured over the week after receiving the antibiotic doses. Our model predicts that increasing antimicrobial susceptibility of the resistant bacteria, fitness costs of resistant bacteria, and increased removal of antibiotics from the colon all lead to improved clearance of resistant bacteria in the low dose study. Moreover, our model suggests that the long-term amount of resistant bacteria is highly dependent on the initial amount of resistant bacteria pre-antibiotic treatment.