Effect of Sub-inhibitory concentrations of ciprofloxacin on e.coli biofilms

Using a standard tube biofilm set up, we subjected the biofilm to a low concentration of antibiotics. A wild type and recA knockout was used to determine the role of the SOS response when exposed to low levels of antibiotics. Through whole genome sequencing we identified two base pair mutations, one was in treB and was only seen in the wild type bacteria, suggesting that it was a response to DNA damage mediated by the SOS response. The second mutation in yebT was seen in both the wild type and the RecA knockouts, suggesting that this mutation operated independently from the SOS response.