PROJECT SUMMARY:
Uropathogenic Escherichia coli (UPEC) is one of the major causative agents of urinary tract infections (UTIs).
With growing frequency of antibiotic treatment failure and slowing of antibiotic discovery, the rate of recurrent
UTIs is poised to continue to increase. Although antibiotic resistant pathogens are of particular concern,
treatment failure can often occur by non-genetic mechanisms, without detectable resistance. One of the non-
genetic mechanisms of antibiotic treatment failure—persistence—is characterized by antibiotic tolerance in a
small group of cells among a susceptible population. Bacterial persisters, which can reversibly exit the antibiotic-
tolerant state following drug removal, is able to repopulate an infection and impede success of treatment.
Persisters are known to be enriched in slow growing populations, where overall cellular activity and metabolism
is reduced; however, there is a lack of knowledge on how the surrounding nutrient environment can affect
bacterial physiology, and how these factors affect susceptibility to antibiotics.
Our central objective is to determine the impact of carbon source availability on UPEC persistence to
fluoroquinolone (FQ) antibiotics, which are bactericidal through the targeting of DNA topoisomerases and the
accumulation of DNA damage. Aim 1 aims to address changes to metabolism, biomolecular synthesis, and DNA
integrity in response to carbon source availability during FQ treatment. We will assess these factors by
performing experiments with fluorescence-based probes, as well as mass spectrometry analysis of metabolites.
These data will elucidate the ways by which carbon source availability can impact the susceptibility of cells to
FQs, allowing us to explore specific mechanisms as potentiation targets. Aim 2 will enable us to understand how
the coordination of DNA damage response changes due to carbon source availability after FQ treatment. We
will deploy powerful genetic approaches and RNA sequencing in E. coli to interrogate the timing of gene
expression and DNA repair. Completion of this aims will provide great insight into the importance of various DNA
repair mechanisms in response to FQ treatment.
Overall, the completion of these aims will reveal metabolic, biosynthetic, and expressional changes that underlie
FQ persistence in E. coli. This information could illuminate potential genes that can be targeted to potentiate the
activity of FQs and reduce resistance development in persister progenies. Additionally, these findings could lead
to interesting implications for clinical infections, with a potential connection between host metabolism and
antibiotic efficacy. This research could highlight the potential of adding glucose, as well as other metabolites, as
supplemented compounds during antibiotic administration to improve the treatment of infections.
