Bacterial defiance as a form of prodrug failure

Brandon Alexander Holt; Gabriel A. Kwong

For example, the nitroimidazole class of antibiotics (e.g., metronidazole, dimetridazole, tinidazole, etc.), which is used to treat anaerobic bacteria (e.g., Enterococcus species, Clostridium species, Helicobacter pylori, etc.) represent prodrugs that are activated by bacterial reductases 57 . Genetic studies have revealed that bacterial resistance to nitroimidazole antibiotics is caused by either 20 partial or complete reduction in expression of genes (e.g., rdxA, frxA, etc.) encoding the reductases that activate the prodrug [58] [59] [60] . These changes in the activating enzyme would decrease the rate of prodrug activation, thereby resulting in a reduced overall BAH, that if below BAHcrit for the system, would result in defiance. The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. It . https://doi.org/10.1101/556951 doi: bioRxiv preprint As bacteria-activated prodrugs are an emerging strategy to treat antibiotic resistant infections 9 , our work may provide strategies for preventing defiance-related resistance mechanisms in new and existing prodrugs. To propose strategies for treating prodrug defiance, we leveraged the transistor-like behavior of prodrugs to design a multi-drug circuit to eliminate defiant bacteria that would normally survive the treatment of a single prodrug. In these 5 experiments, we tested eight discrete combinations of three variables (e.g., nutrients, temperature, and linker substrate) and showed that the multi-drug logic circuit effectively eliminated bacteria in all eight conditions. In future work, different variables (e.g., O2, pH, relative biodistribution, etc.) could be included to increase the range of possible treatment conditions. This would require a quantitative understanding of the relationship between the variable and how it 10