Features of bacteriophage isolation in bovine keratoconjunctivitis

Abstract

Infectious bovine keratoconjunctivitis is a highly contagious disease that is widespread in many countries of the world with developed dairy and meat farming, causing great economic damage. This is a contagious disease characterized by lacrimation, hyperemia of conjunctival vessels, photophobia, serous-purulent discharge, opacification and ulceration of the cornea, deformation of the eyeball in the form of keratoglobus or keratoconus, partial or complete loss of vision of the affected eye of the animal. The main causative agents of keratoconjunctivitis are Moraxella bovis and Moraxella bovoculi. Due to the development of multidrug resistance to various antimicrobial chemotherapeutic drugs, there is a need to search for alternative antibacterial agents, which can include bacteriophages. In this work, the goal was to isolate bacteriophages specific to Moraxella bovis and Moraxella bovoculi. For this purpose, 13 samples were selected from a livestock farm in the Moscow region. According to the results of the spot test, two bacteriophages were obtained from the samples, one had specificity only to Moraxella bovoculi, the second had lytic activity as to Moraxella bovoculi, and to Moraxella bovis. The activity according to the Appelman method ranged from 10^-6 and 10^-7 for Moraxella bovoculi and 10^-4 for Moraxella bovis. According to the Grazia method, the yield was 3.2×10⁷ ; 4×10⁶ for M. bovoculi and 2×10⁴ plaque-forming units for M. bovis. The specificity of the lytic spectrum was confirmed in cultures of Pseudomonas aeruginosa, Staphylococcus aureus and Pasteurella multocida.