FIG 4.

PhageY12Pw that survive well both in vivo and in vitro can reduce their host bacteria in vivo (P. aeruginosa that has evolved resistance to ancestor phages). Phage titer significantly changed over time in wheat bran (A) (upon which housefly larvae breed) and in housefly larval intestines (B) with different treatments. Ctca and Ppca represent housefly larvae samples treated with sterile water and sterile water containing 10⁸ PFU/ml bacteriophage, which was replaced every 24 h, respectively. (C) Pseudomonas aeruginosa in housefly larval gut samples of the Ppca group and Ctca group was determined by plating on selective medium. Ctca and Ppca represent housefly larvae samples treated with sterile water and sterile water containing 10⁸ PFU/ml bacteriophage, which was replaced every 24 h, respectively. Data are shown as the mean ± standard error of the mean (SEM). Repeated measures ANOVA was followed by Sidak correction for multiple comparisons; *, P < 0.05; **, P < 0.01; ***, P < 0.001. (D) The mean phage resistance to ancestral and coevolved phages after 24 h of growth; n = 12 for the control (0 h) (original strains that have not been infected with phage), and n = 12 for single phage treatment every 24 h (bacteria strains that infect ancestral phages and coevolving phages). Multiple comparisons were conducted using a Tukey test and a false-discovery rate (FDR)-adjusted P value of <0.05.