Example 7
This assay included 6 groups of chicks: A1) contaminated with E. coli X-A7122; A2) contaminated with E. coli X-A7122 and treated with phages; B1) contaminated with E. coli CM138; B2) contaminated with E. coli CM138 and treated with phages; C1) contaminated with E. coli MT78; C2) contaminated with E. coli MT78 and treated with phages. The respective concentration of the several (i.e. two to seven, or more) bacteriophages comprised in the cocktail was adjusted to 1e8 PFU/ml. Then, the phages were mixed by adding an equal volume of each in a mixing vessel. The phage cocktail was mixed to grounded feed. The mash was administered to the treated group with truncated pipet tip on day 1. The chicks of all groups were then contaminated with 1e8 CFU with the E. coli strains stated above. The bacterial strains were beforehand genetically modified and selected for nalidixic acid resistance allowing specific enumeration of these strains within the microbial community. None of the commensal strains were found to be resistant to this antibiotic marker.
We observed a reduction of the APEC strains titer in the caeca in the treated groups compared with the untreated groups showing the efficiency of the treatment (
