Figure 6.

In vivo toxicity of E. coli CFT073, IBEC 40, and IBEC 77 in G. mellonella larvae and effective survival concentration for in vivo phage therapy. (A) Different concentrations of IBEC 40 and IBEC 77 phages showed no toxic effects on the survival of G. mellonella larvae over 48 h of inoculation. (B) Survival curve of G. mellonella larvae with effective concentrations of E. coli CFT073 and IBEC 40 and IBEC 77 phages alone and in different combinations with ciprofloxacin (20 mg/kg larva) for studying the prolongation of larvae survival, compared with the bacterial host strain alone. For the individual treatments of phages, the clarification x1 indicates one dose at 1 h post-infection (h.p.i) and the clarification ×2 indicates two doses (the first dose at 1 h.p.i and the second dose at 5 h.p.i). In the combined treatments of phages with the antibiotic, the ▲ clarification in the legend indicates one dose at 1 h.p.i and ▲▲ indicates 2 h.p.i. Larvae were monitored up until 55 h after inoculation. Graphs were plotted with GraphPad Prism version 9.0. Statistically significant differences (* p < 0.05, ** p < 0.01, *** p < 0.001) between all treatments and the E. coli CFT073 were determined with GraphPad Prism version 9.0, by using the Long-rank test and Gehan–Breslow–Wilcoxon test.