Non-antibiotic microbial solutions for bovine mastitis–live biotherapeutics, bacteriophage, and phage lysins

Bovine mastitis is a disease with a multi-etiological nature, defined as an inflammation of the udder. The main treatment for mastitis is the administration of antibiotics–usually directly to the udder. There is an urgent need for novel therapies to treat and prevent the disease, given the widespread emergence of antibiotic resistance and concomitant problems in the treatment of human and animal infections. We provide an overview of treatments for bovine mastitis, with emphasis on probiotics, bacteriocins, bacteriophages (phages), and phage endolysins. Probiotics have in recent years proved to be particularly efficacious in bovine mastitis treatment and prevention. In this case, the mode of action is most likely to be due to stimulation of the host immune response which clears the mastitis pathogen. Bacteriocins have the potential to be incorporated into teat washes and wipes, thus preventing pathogen spread on the farm. Phage therapy is limited by the inability of some phages to replicate in raw milk, as reported for some staphylococcal phages, and by their narrow host specificity. The use of phage endolysins is more promising, by enabling the development of broad host range potent antimicrobials, but additional research is required in terms of efficacy, safety and production.