Potential application of lyophilization in commercial use of bacteriophage preparations in veterinary medicine

Abstract

Microbial contamination in livestock, resulting in foodborne illnesses, poses a serious problem for veterinary medicine. Rapidly growing number of antibiotic-resistant bacterial strains triggers increased interest in phage therapy, which has already been tested against zoonotic pathogens in animals. The aim of the study was to investigate the potential application of lyophilization process in commercial processing of phages. We lyophilized three phages active against common animal pathogens Escherichia coli, Salmonella sp. and Enterococcus faecalis, in the presence of three different cryoprotectants. The activity of phages was determined after 10 days, 1 month, 3 months, 6 months and 1 year storage at room temperature. All conditions of storage were established to consider practical aspects of phages processing. Skim milk appeared to be the most effective cryoprotectant, however the obtained results varied for different phages, suggesting that efficiency of this process was phage-dependent. This in turn, may be problematic during optimization of phage lyophilization for commercial processing. Nevertheless, further commercialization of phage preparations seems to be unavoidable and the development of new methods for phage processing and storage is required.