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Inhibition of the etiological agent of American foulbrood disease using selected essential oils
ZÁLABSKÁ, Adéla
Americal foulbrood disease, caused by etiological agent Paenibacillus larvae is serious disease which affects honey bee that is prohibited to treat with antibiotic in the Czech Republic. If the disease occurs in hive, it is a legal requirement to burn the hive. Essential oils have antimicrobial aktivity and their use can help fighting this dangerous disease. The aim of the bachelor thesis was to verify the bactericidal effect of selected essential oils on the causative agent of the americal foulbrood disease P. Larvae. Another stated aim was to determine the minimum inhibitory and bactericidal concentrations of the selected essential oils. A total of 11 essential oils were used and evaluated both alone and in combination with other essential oils. The evaluation was carried oud on microtiter plates using spectophotometer and on agar medium in petri dishes. The most effective essential oil was garlic oil (Allium sativum bulb oil), which had minimum and bactericidal concentration values of 32 ?l/mg. Other very effective plant essential oils include cinnamon essential oil (Cinnamomum zeylanicum bark oil). The least effective essential oils are carrot oil (Daucus carota sativa seed oil), thyme oils (Thymus serpyllum oil, Thymus vulgaris flower/leaf oil) or oregano oil (Origanum vulgare).
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Impact of honey processing on its antimicrobial activity on bacteria Escherichia coli
ŠTEFANOVÁ, Kateřina
In the theoretical part of my bachelor thesis, I discuss honey, its chemical composition, physical properties and use in medicine, where I mainly describe the antimicrobial activity. Next, I briefly describe the characteristics and pathogenic strains of bacteria Escherichia coli. The aim of the work was to test the handling and processing of honey for its antimicrobial activity. Two indicators of antimicrobial activity were determined, namely the Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) against gram-negative bacteria E. coli. These parameters were tested on 6 samples of extracted honey and then after drying for 12 hours, heating in a water bath at 50 °C until liquefaction (approximately 1 hour) and after heating in a microwave oven at 250 W until liquefaction. The Broth microdilution assay method with spectrophotometric evaluation was used to determine the MIC. MBC was determined by streaking and culturing the bacterium on an agar medium. In addition, the water content and electrical conductivity of the dialed and dried honey samples were determined. The results showed that all of the mentioned processing methods negatively affected the antimicrobial activity, with the worst results being after microwave treatment. Since honey is routinely heat treated in practice, these results can help to choose the most gentle treatment method.
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