Therapeutic use of phage cocktail for controlling Escherichia coli O157:H7 in gastrointestinal tract of mice

Naturally resident and exogenously applied T4-like and T5-like bacteriophages can reduceEscherichia coliO157

“…26,[33][34][35] A number of authors have demonstrated the efficacy of either single or cocktail phage treatments in the laboratory but only a few have shown any meaningful reduction in vivo. [23][24][25]27,28,36,37 Early studies examining phage populations in livestock were born of a concern that they might negatively affect the microbial ecology of the gut (especially the rumen) and thus reduce animal productivity; however, it was found that phage actually help maintain microbial diversity and balance. 38,39 These initial studies centered on bovine ruminal phages, but more recent O157:H7 phage research has moved to the recto-anal junction, the demonstrated major site of colonization in cattle.…”

“…24,25,36,60 This approach applied blindly does not, however, take into account the complexities and kinetics of phage:host interactions. An effective therapeutic cocktail should consist of multiple phages that work "in concert" and not "in conflict" to kill the majority of the targeted bacteria, and then prevent the regrowth of resistant mutants for an extended period, if not altogether.…”

Successes and Failures of Bacteriophage Treatment of Enterobacteriaceae Infections in the Gastrointestinal Tract of Domestic Animals

“…Aerobic, instead of anaerobic, selection may have played a key role in the ability of this bacteriophage to effectively eliminate intestinal carriage of E. coli O157:H7. Multiple researchers have suggested anaerobic environments can affect bacteriophage activity (Bach et al, 2003;Kudva et al, 1999;Raya et al, 2006;Tanji et al, 2005). When Bach and co-workers (2003) tested the effects of bacteriophage DC22 on E. coli O157:H7 in an in vitro fermentation system prior to treating infected sheep, bacteriophage DC22 only decreased microbial levels in the artificial ruminant set up at high multiplicities of infection (MOI), and failure of the bacteriophage to replicate and increase PFU over the course of 120 hours suggests that the bacteriophages may have reduced E. coli by lysis from without rather than by infecting, replicating within, and lysing the cells.…”

“…Subsequent in vivo studies in sheep did not result in decreased shedding of E. coli O157:H7, and bacteriophages were found in the feces for only two days post-treatment. Similarly, Tanji et al, (2005) administered a bacteriophage with promising in vitro test results to E. coli O157:H7 mice with little success. These studies reinforce the need to understand how in vitro conditions relate to the in vivo infection parameters and show the need for an appreciation for the ecosystem where the bacteriophage will be used.…”

Poultry Salmonella Specific Bacteriophage Isolation and Characterization

“…Bacteriophages have been successfully used to treat bacterial diseases in animals (Smith and Huggins, 1983;Atterbury et al, 2003;Huff et al, 2005;Tanji et al, 2005). These instances demonstrated that phage therapy can be as efficient as antibiotics in treating bacterial infections.…”