The results of studies of cultural-morphological, enzymatic and biochemical properties of bacteria of the genus Staphylococcus isolated from samples of biological material from domestic animals and humans are highlighted in the dissertation. The sensitivity to antibiotics of staphylococcal isolates obtained from the milk of cows with mastitis, from pigs, cats, dogs and humans was studied. The
ability of selected bacteria of the genus Staphylococcus to form biofilms was studied. Molecular genetic studies were conducted in order to identify determinants of pathogenicity - genes that cause resistance to methicillin and the formation of biofilms. The effectiveness of the use of different culture media for the recovery of lyophilized strains of staphylococci and the accumulation of their biomass for the purpose of producing standard antigens has been clarified. It was established that the frequency of staphylococci release was: from milk 41,0 %, from pigs 74,1 %, dogs and cats 56,8 %. Coagulase-positive staphylococci predominated among isolates isolated from pigs (45,3 %) and humans (57,9 %), while coagulase-negative ones were isolated from milk (94,2 %) and from companion animals (92,0 %). More often, the ability to hemolysis of erythrocytes was found in staphylococci isolated from pigs (71,0 %), companion animals (84,0 %) and humans (100 %). It was established that polyresistant staphylococci made up 34,2 % of cultures isolated from milk; more than 50,0 %, strains isolated from pigs; 32 % - companion animals and 21,0 % from people. During the study of
staphylococci isolated from milk, it was established that the coagulase-positive strain "133" had simultaneous resistance to 9 out of 13 studied antibiotics, excluding vancomycin, chloramphenicol, gentamicin and tobramycin. Another coagulase-positive strain "136" was resistant to 5 out of 13 studied antibiotics, excluding oxacillin, vancomycin, chloramphenicol, tobramycin, norfloxacin, ciprofloxacin, tetracycline, doxycycline. Coagulase-negative strain "114" was resistant to 9 out of 13 studied antibiotics, namely: benzylpenicillin, oxacillin, ampicillin, erythromycin, tetracycline, doxycycline, norfloxacin, ciprofloxacin, chloramphenicol. among the studied 18 coagulase-positive Staphylococcus spp. 100 % of cultures isolated from pigs were resistant to benzylpenicillin, ampicillin, norfloxacin and ciprofloxacin; to sparfloxacin - 97 %, to ofloxacin - 95,3 %, to levofloxacin - 93,3 %, to lincomycin - 92 %, to gatifloxacin - 87 % of cultures, lomefloxacin - 87% of cultures, to pefloxacin 70 % of moderately resistant and resistant cultures , to tetracycline 52 %, to doxycycline - 28,5 %, to clindamycin - 42 %, to oxacillin moderately resistant and resistant 9 %. The coagulase-negative strain "17" was isolated from cats, which was resistant to 10 out of 13 studied antibiotics with the exception of levofloxacin, fusidic acid and was moderately resistant to doxycillin. Also, strain "30" resistant to 9 out of 13 studied antibiotics, except for chloramphenicol and fluoroquinolones, was isolated from cats. 35,7 % of the strains isolated from cats were sensitive to all studied groups of antibiotics. Strain "19" was sensitive to benzylpenicillin, ampicillin, oxacillin, erythromycin and at the same time resistant to 9 other antibiotics; strain "33" was resistant to benzylpenicillin, gentamicin, tobramycin and fusidic acid and at the same time sensitive to the remaining 9 antibiotics. Among coagulase-negative strains isolated from dogs, one strain "38" was resistant to 12 studied antibiotics except doxycycline. One strain "25" resistant to the group of penicillins and erythromycin and two strains "23" "36" resistant to the group of penicillins were also isolated. Only 27,2 % of studied staphylococcal isolates were sensitive to antibiotics from all groups. 19 strains of staphylococci isolated from patients of one of the hospitals with signs of nosocomial bacterial infections, it was found that 72,7 % (8 out of 11) of coagulase-positive and 100 % of coagulase-negative (8) cultures were resistant to benzylpenicillin staphylococci. 21,1 % of the studied strains were resistant to oxacillin (1 - coagulase-positive and 3 coagulase-negative). The coagulase-positive strain "2" showed simultaneous resistance to penicillin antibiotics, macrolides, and fusidic acid. Coagulase-negative staphylococci "14" "19" were resistant to 12 studied antibiotics except vancomycin and chloramphenicol, and strain "17" was resistant to 11 studied antibiotics except doxycycline, vancomycin and chloramphenicol. The high ability to form biofilms of staphylococci isolated from companion animals (88,0 %) and from sick people (68,4 %) was studied.
