FIG 4.

Survival rates of E. coli isogenic strains treated with 1,000 μg/ml of CIP after 6 h under anaerobic conditions. Survival rates were calculated by dividing the number of CFU per milliliter after CIP incubation by the value obtained at time zero. All results were obtained by at least three independent experiments. Error bars represent standard deviations. Asterisks denote statistically significant differences (P < 0.05 [Student′s t test]) between conditions in comparison to the respective survival rate in Mueller-Hinton for every strain.