FIG 6.
Effect of genetically similar phages on phage-antibiotic combined therapy. A 100-fold diluted subculture of wild-type JJ2528 was incubated for 4 h, centrifuged, washed, adjusted to an OD600 of 1, and inoculated in a 96-well plate coated with phages (ΦHP3 and ΦES12) and antibiotics in LB medium. OD600 was measured every 15 min for a total of 24 h with shaking in between. Synograms (t = 24 h) show wild-type ExPEC treated with ΦHP3 (A) and ΦES12 (B) with antibiotics (ceftazidime and ciprofloxacin). Synograms represent the average reduction percentage for each treatment from three biological replicates: Reduction (%) = [(ODgrowthcontrol − ODtreatment)/ODgrowthcontrol] × 100. The regions above the dashed lines indicate antibiotic-mediated killing with highly effective doses; the regions between the solid and dashed lines represent the interacting regions of the phage and antibiotic, and the regions below the solid lines indicate phage-mediated killing with ineffective antibiotic concentrations.