The thesis is devoted to the study of the properties of Salmonella spp., Citrobacter spp., St. aureus, as causative agents of toxic infections and toxicoses. An analysis of state reports of veterinary medicine and the sanitary and epidemiological service for 2006–2015 showed that among the recognized pathogens of salmonella toxin infections in the territory of the Odessa region, predominantly S. Choleraesuis, S. Dublin, S. Anatum, S. Enteritidis, S. Typhimurium и S. Gallinarum-Pullorum.
Experimental cultures of S. Gallinаrum-Pullorum, S. Enteritidis, S. Dublin, S. Derby и S. Moscow, S. Typhimurium biovar а, which are isolated from food products, possessed typical morphological, tinctorial, cultural and biochemical properties, as well as antigenic structure, according to the determinant of bacteria Bergi (2005). The cultures of S. Typhimurium biovars b and c differed from their inherent phenotypic features: the absence of reduction of sulfite to iron sulphide on bismuth-sulfite agar (BSA), reduced enzymatic activity with respect to arabinose, mannitol and dulcite, antigenic structure was monophasic (O:1,4,5,12; H:i:-). Virulence of monophasic S. Typhimurium biovar b for white mice showed longer. Having infected monophasic cultures of S. Typhimurium mice, the antigenic structure of them was restored, the enzymatic properties were activated, but the culture characteristics on the BSA did not change.
29.4 % of raw milk samples contaminated St. aureus in a concentration of 4.7 ± 0.4 lg CFU/cm3. St. aureus was detected in 60.0 % of positive samples with mastidine test (3.0 ± 0.18–5.8 ± 0.45 lg CFU/cm3) and in 20.0 % of negative mastidin samples (1.2 ± 0.02–3.6 ± 0.19 lg CFU/cm3). Epizootic cultures St. aureus, which were isolated from food, had 9 traditional factors of pathogenicity in 5.6 % of cases, and the remaining 13 variations of 5–8 factors. In highly virulent cultures, plasmocoagulase was detected for 1–4 h, lecithinase in 24 h, and hemolysin for
9–18 h.
The contamination of food products by the bacteria of the genus Citrobacter is 22.6 %, and animal feed — 36.8 %. In cultures of cytobacteria virulence factors (DNA-ase, lecithinase, hemolysin) are defined, their ability to cause symptoms of toxicinfections in white mice (37.9 % of cases) and death with signs of poisoning (11.0 %) is proved. The regimes for their inactivation at 85 ± 1 °C for 10 min and 95 ± 1 °C for 2 min, UV irradiation for 40 min and sensitivity to a number of antibiotics were determined. A high degree of antagonism of Citrobacter spp. to the reference strains, S. marcescens, L. іnnocua to a lesser extent to E. faecalis, Eb. aerogenes, P. vulgaris and St. aureus. Cultures of C. freundii and C. rodentium showed an inhibitory effect on the E. coli reference strain and vice versa, the E. coli strain suppressed the growth of C. koseri, C. farmeri and C. braakii. There was no antagonism tо S. Typhimurium, K. pneumoniae, S. flexneri, L. monocytogenes, Ps. aeruginosa and B. cereus. Between the bacteria of the genera Citrobacter, Salmonella and St. aureus in associations there is a synergy is manifested by increased resistance to antibiotics in comparison with their monocultures, intensive manifestation of hemolytic, lecithinase and DNAase activity of C. freundii, but the synthesis of hemolysins and coagulase is suppressed St. aureus.
In experienced Citrobacter spp. in 100 % of cases the enzyme pyrrolidonyl peptidase is produced irrespective of the species, and Salmonella spp. do not own such an enzyme.
