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Abstract. Potential pathogens of foodborne toxic infections -bacterial contaminants Bacillus cereus isolated from plant raw materials and food products from the Ukrainian region were investigated. When determining of the proportion of isolated bacilli from the plant samples, it was established that the epidemiologically significant microorganisms of Bacillus cereus as agents of food poisoning are the second largest. The average value of contaminated samples of Ukrainian plant raw materials and processed products with Bacillus cereus is 36.2 %. The ability of Bacillus cereus strains identified by a complex of morphological, tinctorial, cultural and biochemical properties, to produce specific emetic and enterotoxins was studied. Molecular genetic diagnosis and detection of the toxin-producing ability of isolated 42 Bacillus cereus strains showed both the possibility of their rapid identification and the presence of specific toxicity genes. Multiplex polymerase chain reaction (PCR) was carried out with specific primers to detect toxicity determined of various bacilli genes: nheA, hblD, cytK, cesВ. The distribution of toxigenic genes is significantly different among the Bacillus cereus isolates from various sources. The nheA, hblD and cytK enterotoxin genes were detected in 100, 83.3 and 61.9 % of the investigated strains of Bacillus cereus, respectively. The cesB gene encoding emetic toxin was detected in 4.8 % of strains. Molecular-genetic PCR-method confirmed that all the isolated strains belong to the Bacillus cereus group, and the ability to produce toxins can be attributed to five groups. The main toxins that produce the investigated Bacillus cereus strains were nhe and hbl enterotoxins encoded by the corresponding genes of nheA and hblD. The enterotoxic type of Bacillus cereus was predominant in Ukrainian region. Studies of domestic plant food raw materials and products have confirmed the need to improve microbiological control of product safety by introducing accelerated specific diagnostics of contaminants by molecular genetics methods.Key words: toxin-producing Bacillus cereus, enterotoxins, emetic toxin, molecular genetic diagnosis, polymerase chain reaction, food safety. Анотація. Досліджено потенційні збудники харчових токсикоінфекцій -токсигенні бацилярні контамінанти Bacillus cereus, виділені з рослинної сировини і продукції харчової промисловості українського регіону. Середнє зна-чення контамінованості Bacillus cereus зразків української рослинної сировини і продуктів її переробки становить 36,2 %. Вивчено здатність штамів Bacillus cereus, ідентифікованих за комплексом морфологічних, тінкторіальних, ку-льтуральних та біохімічних властивостей, продукувати характерні еметичний (блювотний) і ентеротоксини. Молеку-лярно-генетична діагностика і виявлення токсинпродукучої здатності виділених 42 штамів Bacillus cereus показали як можливість їх швидкої ідентифікації, так і наявність характерних генів токсичності. Мультиплексну полімеразну лан-цюгову реакцію (ПЛР) проводили зі специфічними праймерами для вияв...

Recently, possible co-application of probiotics and antibiotics has been widely discussed. This form of combined therapy, because of its commonly recognised advantage, is widely used to prevent antibiotic-associated diarrhoea and induced dysbiosis. Due to the increased application of lactobacilli as probiotics, EFSA has developed a number of requirements concerning their safety and functionality. Every commercial probiotic should be able to obtain the Qualified Presumption of Safety status (QPS). Though QPS is a status attributed to species, individual species differ greatly in their genome content, including those belonging to the genus Lactobacillus. Infectious bacteria and strains that may possess genes responsible for virulence or antibiotic resistance should not be used lest pathogenic genes be passed on to other species. The human gastrointestinal tract, due to the immense amount of bacteria and the close contact between them, is a possible place for gene transfer. The main hazard is the transfer of antibiotic resistance determinants from commensal bacteria and the emergence of resistance to common microbial infections, which can prevent successful antibiotic treatment. A condition of using bacterial strains as probiotics is their safety, in particular, the absence of antibiotic resistance determinants. The purpose of the work was to determine the antibiotic sensitivity/resistance of lactobacilli isolated from different sources in the Odesa region. By the disc diffusion method, it has been determined how sensitive the 13 lactobacilli strains isolated from auto-fermented vegetables, raw meat, and newborn children’s gastrointestinal tract are to 15 antibiotics with different mechanisms of action. It has been established that the sensitivity/resistance depended on the strain and specific antibiotic. An obvious feature of the strains under study was their higher sensitivity to antibiotics that inhibited the synthesis of protein and nucleic acids, as opposed to antibiotics that affected the synthesis of the cell wall and cytoplasmic membrane. The results of the comprehensive research have allowed selecting the Lactobacillus spp. strains O1, B4, 175, M2, and M3 as the most promising for the creation of probiotic preparations.

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Purpose. To evaluate the effectiveness of bacteriocin of Enterococcus italicusONU 547 and essential oils individually and in combination against indicatorstrains of opportunistic pathogens. Methods. The antagonistic activity of essential oils and bacteriocin was determined by the optical density of the bacterial suspension of test strains (Salmonella enterica NCTC 6017, Escherichia coli АТСС 25922, Pseudomonas aeruginosa АТСС 27853, Pseudomonas putida KT 2440, Enterococcus faecalis АТСС 29212, Klebsiella pneumoniae АТСС 10031,Staphylococcus aureus АТСС 25923). The index of fractional inhibitory activity(FIC) was calculated by adding the FIC values of bacteriocin E. italicus ONU 547and the studied essential oils. The results. The maximum antimicrobial effect was caused by the essential oils of Anisum officinalis and Melissa officinalis, which suppressed the growth of test strains more than 50.0%. When using bacteriocin of E. italicus ONU 547 suppression of viability of indicator strains did not exceed 30.0%. Experimental combinations of essential oils and bacteriocin caused 4 types of consequences: synergy effect; additive effect; antagonistic effect; interactiveeffect (no interaction effect). In most cases, the combined action of bacteriocinand essential oils caused an additive effect. Conclusions. This study demonstrated the potential of using different combinations of natural antimicrobial compounds. The obtained results provide grounds for further development and optimization ofcombinations of essential oils and probiotic strains of microorganisms for use in food and pharmaceutical biotechnology.