Intestinal microbiomes of calves in dysbacteriosis

In young farm animals, intestinal dysbiosis is a consequence of non-observance of the conditions of keeping and feeding, as well as the irrational use of antibacterial drugs. With this pathology, opportunistic microflora dominates in the gastrointestinal tract, in particular, bacteria belonging to the Enterobacteriaceae family. The species composition of bacteria isolated from 14 calves kept in unfavorable conditions in the early postnatal period (5-10 days) with intestinal dysbiosis was studied. Calves are kept in different premises of the same livestock farm in the Omsk region. Rectal swabbings were used as material for bacteriological research. 4 types of opportunistic microorganisms belonging to the Enterobacteriaceae family (E.coli of enteropathogenic serotypes O2, O33, O117 and O78, Proteus mirabilis, Citrobacter freundii and Providencia rettgeri), 2 species of microorganisms of the Enterococcaceae family Enterococcaceae genus (Enterocoсcus faecium and Enterocoсcus faecalis), as well as Pseudomonas aeruginosa were identified. The abovementioned cultures of microorganisms were identified using both classical and modern microbiological methods. The most accurate biochemical identification of Providencia rettgeri was carried out using the RapID ONE System kit. The pathogenicity of microorganisms was determined by setting a bioassay on white mice. The most pathogenic cultures were E.coli cultures of enteropathogenic serotypes O2 and O33, Enterococus faecalis and Pseudomonas aeruginosa. Using the disk-diffusion method, the sensitivity of the isolated cultures to 14 antibiotics used in veterinary medicine was determined. On the basis of this study, antibacterial drugs with the largest zone of inhibition of the growth of microorganisms - lincomycin, cefuroxime and fosfomycin - are recommended for effective therapy of sick calves.