| Abstract [eng] |
DNA Fingerprinting of Listeria monocytogenes Using Pulsed-field Gel Electrophoresis The aim of the study was to determine the genetic profiles of Listeria monocytogenes detected in food by the method of pulse-field gel electrophoresis. Objectives: 1. Identify L. monocytogenes strains using PulseNet standard operating procedure. 2. Perform L. monocytogenes profile analysis using “BioNumerics” software. 3. Compare the obtained L. monocytogenes strains with each other. 4. Evaluate the relatedness between strains, to determine the dependences of the food and L. monocytogenes strains. Listeriosis is a contagious disease of animals and humans caused by Listeria monocytogenes. Listeriosis is most commonly spread through food, which can be contaminated at any stage of the food chain “from farm to fork”. Appropriate and effective measures to detect and control these pathogens are necessary to reduce the prevalence of Listeria and the risk to public health. In this study, L. monocytogenes was detected in 44 products using ISO 11290-1: 2017 procedure. Through the analysis of L. monocytogenes conducted in this thesis, optimal conditions were selected using PFGE method: buffer flow rate 550 mL / min, temperature 14 ˚C, process duration AscI 15 h. 40 min, ApaI 14 h. 50 min. “BioNumerics” software generated dendrogram was used to assess the relatedness of bacterial strains. Of the 44 strains obtained, 4 strains were inseparable, 10 groups of strains were> 80% similar to each other, 13 strains had an identity of less than 80% and 3 single, least identical strains (31–36,2%). It was found that different product types (e.g. smoked meat, raw meat, etc.) will provide different strain results. Due to probable environmental contamination, only two cases of different types of products had shown the same strain results. |
