Randomized control trials using a tablet formulation of hyperimmune bovine colostrum to prevent diarrhea caused by enterotoxigenic Escherichia coli in volunteers

Abstract

Objective. Enterotoxigenic Escherichia coli (ETEC) is the leading cause of travelers' diarrhea. The aim of this study was to investigate the ability of a powdered extract of hyperimmune bovine colostrum to protect against diarrhea in volunteers challenged with ETEC. Materials and methods. Tablets were manufactured from a colostrum extract from cattle immunized with 14 ETEC strains, including serogroup O78. Two separate randomized, double-blind, placebo-controlled trials involving 90 healthy adult volunteers were performed to investigate the ability of different tablet formulations to protect against diarrhea following an oral challenge with an O78 ETEC strain. Results. The first study with 30 participants evaluated the efficacy of tablets, containing 400 mg of colostrum protein, taken thrice daily with bicarbonate buffer. This regimen conferred 90.9% protection against diarrhea in the group receiving the active preparation compared with the placebo group (p = 0.0005). The second study examined the efficacy of tablets containing 400 mg colostrum protein given with buffer (83.3% protection; p = 0.0004) or without buffer (76.7% protection; p = 0.007), and tablets containing 200 mg colostrum protein given without buffer (58.3% protection; p = 0.02), compared with placebo. The difference between buffered and unbuffered treatments was not significant (p > 0.1). Conclusions. Active tablet formulations were significantly more effective than placebo in protecting volunteers against the development of diarrhea caused by ETEC. These results suggest that administration of a tablet formulation of hyperimmune bovine colostrum containing antibodies against ETEC strains may reduce the risk of travelers' diarrhea.

Key Words::

• Enterotoxigenic Escherichia coli
• hyperimmune bovine colostrum
• travelers' diarrhea
• volunteers

Acknowledgements

The authors are grateful to Anne-Marie Bordun for technical assistance. Financial support for this study was provided by Anadis/Immuron Limited, Melbourne, Australia, who also provided the tablets. Research in RRB's laboratory is supported by the Australian National Health and Medical Research Council.

Declaration of interest: All authors received funds from Anadis Limited to perform and analyze this study. RRB owns shares in Immuron Limited.