Figure 5. Kinetics of bacterial growth in the presence of phage Giraffe or ciprofloxacin. B. anthracis HS2–7, a ciprofloxacin resistant strain, was grown at 37°C in tryptic soy media and 1% (v/v) of tetrazolium dye. The wells designed to receive bacteria were seeded with 10⁶ cells. The Giraffe phage PFU ranged from 10⁸ PFU to 10² PFU and ciprofloxacin concentrations ranged from 32 µg/ml to 0.5 µg/ml. One well was used as a phage only control and another as a bacterial positive control. The experiments were performed with (A) B. anthracis Sterne 7702 plus ciprofloxacin, (B) HS2–7 plus ciprofloxacin. (C) HS2–7 plus ciprofloxacin and Giraffe phage and (D) HS2–7 plus Giraffe.