Staphylococcus aureus is one of the most important microorganism in the process of raw milk production and has significance for people’s health as it causes dangerous microbial contamination of dairy production. Furthermore, raw milk and the environment of livestock farms may be potential vehicles for distribution of antibiotic-resistant strains of S. aureus. The aim of the present study was to establish antibiotic sensitivity profiles of S. aureus depending on its origin from dairy farms, with a special focus on methicillin-resistant isolates. A total of 165 samples were collected for investigation in the period 2014–2016 from 5 dairy farms in Ukraine. All samples were analyzed for the presence of S. aureus using the Baird Parker Agar with Egg Yolk Tellurite Emulsion. Typical staphylococcal colonies were examined morphologically and for presence of coagulase and hemolysin activities. From these, positive samples for S. aureus were 62 (37.6%): 4 (6.5%) raw milk, 17 (77.4%) swabs of udder skin, 18 (29.0%) milk from cows with subclinical mastitis and 21 (33.9%) environmental samples. The standard disk diffusion method was used to determine sensitivity of S. aureus isolates to 10 antibiotics. The antimicrobial sensitivity profiles of S. aureus isolates showed differences between them, which depends on the origin of the isolates. Our results demonstrated that most of S. aureus isolates were resistant to penicillin, oxacillin and vancomycin. Of the 62 S.aureus isolates, 20 (32.3%) and 5 (8.1%) were found to be multiresistant to 3 different antibiotics, 6 (9.8%) isolates to 4 antibiotics, 12 (19.4%) and 3 (4.8%) to 5 antibiotics (P10, OX1, VA5, L10, TE30 and P10, OX1, VA5, CIP10, TE30 respectively). All isolates resistant to penicillin and oxacillin were typed by mec A gene in PCR with two primers (MecA147-F and MecA147-R). The results show that 66.7% of these isolates yielded a mecA product. The information obtained from this study is useful for understanding the prevalence of S. aureus and its antibiotic sensitivity in dairy farms and can be useful for local and national monitoring or for designing specific control programs of methicillin- and multiresistance isolates present in the food chain of milk production.

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The foodborne pathogens cause serious public health problems in each country. In this regard, microbiological investigation is included in food safety management of the food chain. Molecular methods and mostly polymerase chain reaction (PCR) are considered highly sensitive, specific and rapid methods for pathogens detection from raw material and food. This study describes the using of specially designed and highly specific primers for PCR to identify 5 common and especially dangerous causeve agents of food poisoning and disease and to determine their level of distribution in food of animal and plant origin. The studies included the identification of methicillin-resistant Staphylococcus aureus (MRSA) and Cronobacter spp. (E. sakazakii) from raw milk, Shiga toxin-producing strains of Escherichia coli (STEC) from beef and swine carcasses, Bacillus cereus and Clostridium perfringens from various types of plant and animal raw materials and products of its processing - fruits, vegetables, berries, dried and preserved products, food concentrates, half-canned food. A total of 397 food samples were investigated to detect these pathogens using classical bacteriological methods and PCR. It was found that the distribution of foodborne pathogens in the studied products of animal and plant origin was as follows: Staphylococcus aureus (MRSA) and Cronobacterspp. (E. sakazakii) in raw cow milk in 6.5% and 19.4% of cases, respectively; shiga-toxin-producing Escherichia coli (STEC) from beef and pork carcasses in 8.1% and 5.7%; Bacillus cereus and Clostridium perfringens from different types of plant and animal raw materials and their processing products averages 27.5 % and 7.7 %, respectively. The advantages of molecular biological methods to which the PCR method relates, include their speed, as well as the specificity of identification of microorganisms by the features of genetic regions of genes that carry information about their pathogenicity factors. It has been found that the rate of detection of these pathogens when using the PCR method in comparison with classical methods increases at least 5-9 times. This data will be useful for assessing microbiological risk and will help authorities develop strategies to reduce consumer health risks.

Staphylococcus aureus is a pathogenic microorganism that causes a wide range of infectious diseases of humans and animals. Staphylococcus aureus produces a large number of toxins, in particular enterotoxins, which enter the body together with food and cause disorders in the gastrointestinal tract. Moreover, S. aureus has several mechanisms of antibiotic resistance, which greatly complicates prevention of bacteria spread as community-acquired and nosocomial infections. The aim of the work was to determine and compare the differences in size of methicillin-resistant strains of S. aureus with different resistance mechanisms by scanning electron microscopy (SEM). Methods. Disc diffusion method was used to establish the mechanism of antibiotic resistance of the obtained isolates. After description of antibiotic resistant and selection of S. aureus isolates with resistance to penicillin and oxicilin, an SEM of the strains and a further comparison of their morphological characteristics, in particular cell size, with the help of Djmaizer v.5.1.10 software was carried out. Results. 54 isolates of S. aureus, obtained from various environmental objects, dairy farms and food products, were tested. PCR revealed sequences of the mecA gene, which is responsible for bacteria resistance to beta-lactams. We determined the cells size of S. aureus isolates resistant to penicillin and oxycillin and performed a comparative analysis of their morphological characteristics using SEM. Conclusions. In the course of the study, it was found that S. aureus isolates with mecA gene (mecA+) have smaller cell size than S. aureus isolates without mecA gene (mecA-).

Honey is natural product, which is produced by honeybees and due to contain of minerals, vitamins, simple sugars, organic acids, antioxidants and enzymes, it is considered as product with good nutritional and therapeutic properties. All beneficial characteristics of honey are reduced if it is contaminated with extraneous chemicals include pesticides. The purpose of this research was to study pesticides residues accumulation in the flowers of different types of melliferous plants, bee pollen and honey obtained from Odessa Region during 2015–2017 years. A total of 121 samples of flowers of melliferous plants and trees, 78 samples of bee pollen and 104 samples of honey were investigated with gas-liquid chromatography method. We found that all investigated samples were positive to such organochlorine pesticides as α, β, γ–isomers of hexachlorocyclohexane and dichlorodiphenyltrichloromethylmethane and its derivatives in different concentration. Our studies determined that high level of organochlorine pesticides was in samples of sunflower flowers whith average concentrations of α, β, γ–isomers of hexachlorocyclohexane 7.51±0.04 μg/kg, and DDT 6.98±0.02 μg/kg. Flowers of buckwheat and others field herbs (including as wild herbs as fodder crops) had even less concentration of these pesticides. Besides, the obtained results show that in the flowers of fruit trees (cherry, apple, pear, cherry, peach, cherry plum) had less concentration of studied pesticides in compere to forest trees (white acacia, linden). The results of bee pollen and honey samples examination have shown the same situation. The highest concentration of α, β, γ–isomers of hexachlorocyclohexane and dichlorodiphenyltrichloromethylmethane was in sample from sunflower origine with average consentration 3.52±0.05 and 3.77±0.03 μg/kg in bee pollen, 2.74±0.01 and 2.53±0.03μg/kg in honey respectively. However, the detected concentrations of pesticide residues in all samples were lower than the maxim admissibile limits, according to national and EU standards. Despite this, we suggest that regularly monitoring of pesticide residues in melliferous plants and apiculture products at national level need to grantee of quality and safety of honey and protection of consumers` health.