Number of E. coli bacteria in heart, liver, and spleen organs over 49 days of infection. (a) Heart; (b) Liver; (c) spleen; PC: positive control, E. coli challenged, without phages; PC+MHH6, PC+PR2: positive control plus MHH6 or PR2 phage, respectively; PC+MHH6PR2: positive control plus both MHH6 and PR2 phages.