Examining how starvation modality impacts persistence of Pseudomonas aeruginosa to fluoroquinolones

Abstract

The human body contains different niches whose nutrient compositions are variable, and at times invading bacteria will face starvation due to lack of specific nutrients. Previous work has shown that the type of starvation that bacteria undergo can affect persistence levels. Persisters are a subpopulation of bacteria that die more slowly from antibiotic treatment than the overall population and can pose a problem for the treatment of bacterial infections. The Brynildsen group has shown that E. coli cultures grown in single-nutrient starved media show different persistence levels to fluoroquinolones (FQs) depending on the nutrient they are starved for. Motivated by this finding, this project aimed to explore whether the persistence of P. aeruginosa, another Gram-negative bacterium with distinct metabolic preferences, depended on the type of missing nutrient (phosphorus, magnesium, nitrogen, carbon). Additionally, we aimed to explore whether DNA double strand break (DSB) repair systems were important to persister survival in different starvation conditions. We observed that P. aeruginosa persistence depended to some extent on the type of starvation and that recA, which is involved in homologous recombination and the SOS response, was important for the survival of persisters uniformly. These results suggest that targeting of RecA could be a viable means to reduce treatment failure from P. aeruginosa FQ persisters.