Evaluation of Efficacy of a Bacteriophage System in Preventing or Modulating E. coli  O157:H7 Infection of Cattle

Objectives

To determine if cattle given a bacteriophage product specifically targeted for E. coli O157:H7 will reduce the probability of infection with E. coli O157:H7 and/or the amount of E. coli O157:H7 fecal shedding, given infection and this is proven, to determine which route of administration, in feed or in water, provides the best reduction in colonization/shedding.

Conclusions

The average shedding level in Trojan calves did not differ significantly between control and phage-treated groups. Similarly the average shedding level did not differ significantly among in-contact calves. Though a lower percentage of incontact calves in the phage-treated groups were positive on all post-challenge days except day 14, the difference was not significant. As shown by the distribution of maximal shedding levels, E. coli O157:H7 was detected at least once in feces of 24/24 (100%) control in-contact calves and in 22/24 (92%) of phage-treated in-contact calves. The distributions of maximal shedding level were similar and not significantly different. Though there was a slight tendency for a lower distribution among phage-treated calves, the difference was not significant.

Deliverable

This study demonstrated that this specific strain of bacteriophage was not effective in reducing E. coli O157:H7 in cattle. This study did, however, establish a model system (Trojan Calf Model) for studying fecal shedding of E. coli O157:H7 in cattle.