POTENTIAL APPLICATION OF LYOPHILIZATION IN COMMERCIAL USE OF BACTERIOPHAGE PREPARATIONS IN VETERINARY MEDICINE

Microbial contamination in livestock, resulting in foodborne illnesses, poses a serious problem for veterinary. 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 E. coli, Salmonella and Enterococcus, 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.Key words: bacteriophages; lyophilization; freeze-drying; long-term preservation of bacteriophages MOŽNOSTI UPORABE LIOFILIZACIJE V KOMERCIALNE NAMENE ZA PRIPRAVO BAKTERIOFAGOV V VETERINARSKI MEDICINIMikrobiološka kontaminacija hrane v živinoreji, ki povzroča bolezni, predstavlja resen problem v veterinarski medicini. Hitro naraščajoče število bakterijskih sevov, odpornih proti antibiotikom vzbuja vedno večje zanimanje za uporabo t.i. fagoterapije, zdravljenja z bakterijskimi virusi bakteriofagi, ki je bila že preizkušena kot metoda za preprečevanje okužb pri živalih. Cilj raziskave je bil proučiti potencialno uporabo postopka liofilizacije za komercialno obdelavo fagov. Liofilizirali smo tri fage, aktivne proti skupnim živalskim patogenom Escherichia coli, Salmonella sp. in Enterococcus faecalis v prisotnosti treh različnih krioprotektantov. Dejavnost fagov je bila določena po 10 dneh, 1 mesecu, 3 mesecih, 6 mesecih in 1 letu skladiščenja pri sobni temperaturi. Vzpostavljeni so bili vsi pogoji shranjevanja, z namenom upoštevanja praktičnih vidikov obdelave fagov. Posneto mleko je bilo najučinkovitejši krioprotektant, vendar so se dobljeni rezultati razlikovali pri različnih fagih, kar kaže na to, da je učinkovitost postopka odvisna od v