The Australian dairy industry constitutes a major part of the agricultural sector and contributes a net profit of $35 billion per annum. However, disease within the dairy industry imposes significant economic losses each year. The most prevalent disease within the dairy industry is Bovine Mastitis. Currently, mastitis is treated through antibiotic therapy, which is losing effectiveness due to its misuse, thus resulting in antibiotic resistance. Recent research has shifted to alternative therapeutics to treat bovine mastitis, with bacteriophages receiving the most attention.
This study aimed to further characterise bovine mastitis associated bacteria and aid in the development of more effective phage therapies against this devastating disease. Raw bovine milk and teat skin samples from mastitis positive cows were obtained from farms within the rural Victorian area. The samples demonstrated a high diversity of bacteria, with many being identified as unique genera and not those typically associated with bovine mastitis. Of the bacteria isolated, many possessed high resistance to the three most common antibiotics used to treat bovine mastitis; ampicillin, penicillin and streptomycin. Two bacteriophages were isolated against two separate bovine mastitis-associated bacterial pathogens, both belonging to the Siphoviridae family, with one bacteriophage being novel.
These results highlight the diversity of bacteria associated with bovine mastitis and the high prevalence of antibiotic resistance among these pathogens. This study presents the possibility of phage therapy as an alternative therapy. However, further work is required before this therapy may be applied in a large scale across the dairy industry.