Efficacy of an Optimised Bacteriophage Cocktail to Clear Clostridium difficile in a Batch Fermentation Model

Abstract

Clostridium difficile infection (CDI) is a major cause of infectious diarrhea. Conventional antibiotics are not universally effective for all ribotypes, and can trigger dysbiosis, resistance and recurrent infection. Thus, novel therapeutics are needed to replace and/or supplement the current antibiotics. Here, we describe the activity of an optimised 4-phage cocktail to clear cultures of a clinical ribotype 014/020 strain in fermentation vessels spiked with combined fecal slurries from four healthy volunteers. After 5 h, we observed ~6-log reductions in C. difficile abundance in the prophylaxis regimen and complete C. difficile eradication after 24 h following prophylactic or remedial regimens. Viability assays revealed that commensal enterococci, bifidobacteria, lactobacilli, total anaerobes, and enterobacteria were not affected by either regimens, but a ~2-log increase in the enterobacteria, lactobacilli, and total anaerobe abundance was seen in the phage-only-treated vessel compared to other treatments. The impact of the phage treatments on components of the microbiota was further assayed using metagenomic analysis. Together, our data supports the therapeutic application of our optimised phage cocktail to treat CDI. Also, the increase in specific commensals observed in the phage-treated control could prevent further colonisation of C. difficile, and thus provide protection from infection being able to establish.

Review article: bacteriophages in gastroenterology—from biology to clinical applications

“…90 In pre-clinical studies, phage cocktails efficiently reduced C difficile growth and proliferation. 91,92 These results open the possibility of phage therapy being used in patients with C difficile infection and in patients at risk of developing these infections. However, strictly lytic phages targeting C difficile are yet to be found and described, complicating the use of this phage therapy in humans.…”

“…In another trial, the transfer of sterile filtrates from donor stool was sufficient to decrease symptoms in five patients with symptomatic C difficile colitis, possibly due to viral particles transmission . In pre‐clinical studies, phage cocktails efficiently reduced C difficile growth and proliferation . These results open the possibility of phage therapy being used in patients with C difficile infection and in patients at risk of developing these infections.…”

Phage Therapy: Going Temperate?

“…Subsequent tests in a hamster model demonstrated the potential of the lytic-temperate phage cocktail by reducing bacteria colonization at 36 h postinfection and delaying the onset of symptoms by 33 h [41]. In another study, a cocktail of four temperate phages infecting C. difficile was shown to completely eradicate the bacterial load in fermentation vessels spiked with faecal slurries [42]. Curiously, treatment also resulted in the increased presence of commensal bacterial species, which may provide protection from further recolonization by C. difficile.…”

Indications and Limitations of Phage Therapy in Human Medicine: Personal Experience and Literature Review

“…An interesting fact has been revealed in vitro, a strong adsorption of bacteriophages on a model of human cells, which would promote bacteriophage-bacterial interactions [79]. Note also the interest of using an optimized cocktail of bacteriophages [80]. Finally, as suggested in one case study [81], could one hypothesize that faecal microbiota transplants in this indication might represent an effective treatment by the implantation of specific bacteriophages present in the donor [82]?…”