(565g) A New Strategy for Persister Control

One major mechanism that contributes to the failure of current antibiotic treatment is the formation of persister cells, a dormant subpopulation exhibiting high-level tolerance to antibiotics. During antibiotic treatment, persisters remain arrest and transiently repopulate once the antibiotic is withdrawn, causing the failure of treatment and relapse of many infections. Recently, we reported a new strategy for persister control that leverages the dormancy characteristic of persisters and reduced drug efflux activities to increase the intracellular accumulation of the antibiotic, eravacycline. This led to effective killing of Escherichia coli. persisters cells (by 3 logs when treated at 100 µg/mL). This motivated us to test eravacycline on other pathogenic species such as Pseudomonas aeruginosa. Our results demonstrated that eravacycline is effective in killing P. aeruginosa PAO1 (wild-type) and PDO300 (mucoid mutant) persisters cells (99.7 ± 0.0% & 99.0 ± 0.1%, respectively). We also tested the effects of eravacycline on biofilm associated persister cells given that biofilms play a major role in chronic infections. With a concentration of 100 µg/mL, eravacycline reduced the number of viable biofilm cells of PAO1 and PDO300 by 99.9 ± 0.8% and 99.6 ± 0.4%, respectively. In addition, to testing the new strategy against other pathogenic species, we utilized the results from the E. coli data to find new persister control agents. Here, we optimized a chemoinformatic clustering algorithm to filter a chemical compound library to a subset that are similar to the chemical properties of previously proved positive candidates that can sensitize E. coli persisters. From this subset, compound 1b showed potent activity against E. coli persister cells (killing 95.5 ± 1.7%). Collectively, these findings reveal that persister formation may cause enhanced penetration for certain antibiotics which can lead to more killing of tolerant population under normal conditions.