Bacteriophages as emerging-therapeutic agents for overcoming antibiotic resistance in livestock infections

Livestock suffer from several bacterial infections leading to various ailments, including the respiratory, reproductive, systemic, and mainly the enteric diseases; which result not only into a major decline in their productivity, but also a great financial loss on a global scale. The current treatment measures for most of these bacterial infections constitute mainly the antibiotics. However, an extensive use of antibiotics in the past few years, has resulted in the origin and spread of mutant bacterial strains exhibiting multiple resistance against most of the available antibiotics, many of these mutants acquiring the capability of forming biofilms that hinder drug penetration. This global increase in antibiotic resistance has necessitated the need for the search for alternative treatment measures to combat infectious diseases in livestock. Bacteriophage or “phage therapy” is a viable alternative approach in this direction, as the phages are not only host-specific- targeting specific bacteria without having any adverse effect on the beneficial microflora, but also have the potential to be effective in penetration of biofilm layer formed by the resistant bacteria. Further, phages are ubiquitous, and can be easily isolated from soil, sewage, water bodies, food products, humans and animal skin, saliva, stool etc.; thus, increasing the likelihood of finding a large variety of phage isolates having the potential to be used as antimicrobials against different infectious agents. Phage therapeutics includes monophage therapy, which involves the application of a single phage; phage cocktail therapy, which utilizes multiple phages; or the use of genetically altered phages. The present paper discusses the potential of phage therapy as an alternative for antibiotics to control bacterial infections in livestock, different forms in which it can be applied, as well as identifying key challenges that are currently preventing its widespread clinical use and successful implementation.