Dissociated forms of moraxella isolated from the affected eyes of cattle

Abstract

The dissociation phenomenon of epizootic cultures of Moraxella was studied. The study was conducted in economic entities of Almaty region of the Republic of Kazakhstan for 233 heads of cattle with clinical signs of keratoconjunctivitis. Isolation of the causative agent of Moraxella was performed by bacteriological washes from the conjunctival sacs of the eyes of animals. The laboratory study was carried out according to the approved methodological guidelines. It was found that bacteria of the genus Moraxella dissociate when grown on a solid nutrient medium for more than 6 hours in a thermostat at 37 °C. The bacteria were studied by the following methods: staining according to White-Wilson, thermoagglutination and acriflavine assay. When evaluating the grown colonies according to White-Wilson, the optimal dilution for crystal violet was found to be 1 : 2000, and for gentian violet stain 1 : 1000. In this case, the colonies in the S-form have a dark purple color with a metallic tint, and the dissociated colonies in the R-form do not stain. In the presence of dissociated cells, precipitation (thermoagglutination), sediment formation and clearing of the supernatant fluid at 90 °C for 30 minutes were noted. The suspension of undissociated colonies remained cloudy. When weighing microbial cells isolated by a bacterial loop from individual grown colonies in a solution of acriflavine, dissociated bacteria stick together to form conglomerates. When studying the antigenic activity of the S-, R- forms of Moraxella, it was revealed that the activity of the S-antigen significantly exceeded that of the R-forms. Data on the dissociation of Moraxella cultures can be used for the development of diagnostic and prophylactic drugs against moraxellosis in cattle.