Abstract
In the last decade, many researchers have noted a significant increase in various pathologies in domestic and farm animals caused by saprophytic fungal species. Clinically, they manifest themselves as local lesions of the skin and coat, or are accompanied by systemic lesions of the internal organs of animals. Fungi of the genus Alternaria are most often associated with plant pathologies, although cases of animal diseases caused by the representatives of this genus have been described in the scientific literature. The purpose of the work was to isolate the fungus A. alternata on special nutrient media, to study its cultural, morphological and biological properties. For this purpose, samples of biological material were taken from a horse with clinical signs of skin damage. Molecular genetic studies, species identification and determination of the biological properties of the isolated culture were carried out using approved methodological recommendations and determinants of pathogenic and conditionally pathogenic fungi. The cultural, morphological (phenotypic), keratinolytic, biochemical, and molecular genetic properties of an opportunistic species of the microscopic fungus A. alternata have been studied. The isolate was assigned the number 15.23.7.1H; it formed a greenish-brown airy and various shades of black substrate mycelium. Its microstructures were represented by coffee-brown mycelium and conidia. Biochemical properties were characterized by the ability to absorb mannitol and urea, poor absorption of glucose, and the inability to break down sucrose, maltose, lactose, casein, gelatin, and peptone. It had pronounced β-hemolytic and keratinolytic activity. Molecular genetic studies have established the identity of the nucleotide sequences of isolate 15.23.7.1H of A. alternata with the strain sequences published in GenBank. Its nucleotide sequences are deposited in the GenBank database under the number PV793443.1.