Pathogenicity of Enterobacter cloacae strain 140 in C. elegans and efficacy of Enterobacter phage myPSH1140 against E. cloacae infections. The control group consisted of C. elegans fed with E. coli OP50 and exposed to E. cloacae strain 140 (OD600 = 0.6) that kills C. elegans in liquid medium. Twenty nematodes were used in each group. Representative survival curves of C. elegans following infection by E. cloacae strain 140 in (A) liquid medium consisting of M9 buffer and E. cloacae culture, Enterobacter phage, heat-inactivated bacteria and (B, C, D) survival curves of C. elegans following infection with E. cloacae strain 140 and treatment with Enterobacter phage, therapeutic and prophylactic treatment. (B) Survival curves of C. elegans infected and treated with bacteria and phage ratio of 1:1, i.e., 105 CFU/mL and 105 PFU/mL. (C) Survival curves of C. elegans infected and treated with bacteria and phage ratio of 1:10, i.e., 105 CFU/mL and 106 PFU/mL. (D) Survival curves of C. elegans infected and treated with bacteria and phage ratio of 1:100, i.e., 105 CFU/mL and 107 PFU/mL. The survival curves were plotted using the Kaplan-Meier method, and the log-rank test was used to analyze the difference in survival rates in GraphPad Prism 7.0. A statistically significant difference (P < 0.05) was observed in the treatment groups.