Targeting DNA Repair Mechanisms in Bacterial Persisters

Bacterial persisters, cells able to survive high concentrations of antimicrobial agents, are problematic in the medical field due to being responsible for recurring infections, and in industrial settings due to causing contamination in pipes. Furthermore, bacterial biofilms add complexity due to being more enduring than stand alone planktonic bacteria. The inability to successfully eradicate persisters present in patients with recurring bacterial infections and from industrial pipes has prompted interest in targeting persisters through metabolomics. Moreover, interest has expressed in determining the distribution of persisters in biofilms, if any, and why persisters would be more localized in one area than in another. Targeting the DNA repair mechanisms of bacteria, and mapping persister distribution in biofilms are of much interest. The expression of RecA, a protein essential for catalyzing the SOS response for damaged DNA, was targeted in wild type E.coli in order to create RecA lacking E.coli mutants. The mutants were then treated with ofloxacin, a fluroquinolone that causes DNA damage, in order to examine the effects of inhibiting the SOS response. Separately, wild type E.coli biofilms were grown and subsequently sectioned into different categories, with the determining factor being color, to then be treated with antibiotics in order to determine the distribution of persisters. The implications of this study show that targeting DNA repair mechanisms in bacteria can lead to a significant reduction of persisters, as well as that persisters in biofilms are not localized in some areas more than others despite differences in color.