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Screening výskytu genů rezistence u izolátů E. coli ze selat
Havranová, Daniela
Escherichia coli, especially its pathogenic strains, is a common cause of diarrheal disease in weaned piglets, which can lead to deaths and thus reduced pig production. To prevent these problems, previously piglets were given antibiotics and later high doses of zinc oxide after weaning. But bacteria have been found to be able to develop resistance to both antibiotics and high doses of zinc. There is also environmental contamination with both antibiotics and zinc, which is why there have been legislative restrictions on both substances. Other alternatives to these substances are being sought, and phosphate-based zinc nanoparticles could be one of them. This Bachelor thesis, therefore, focuses on determining the presence of antibiotic resistance genes in E. coli isolates from piglet faeces after weaning, fed on zinc oxide and zinc phosphate-based nanoparticles. Furthermore, a screening methodology for selected resistance genes was proposed and the incidence rates of aminoglycoside resistance genes, colistin and ꞵ-lactam antibiotics were established among isolates. Zinc oxide supplementation has the lowest impact on the development of resistance to ꞵ-lactam antibiotics in terms of the frequency of E. coli positive isolates. ZnO feed supplementation has been capped since 2022 and the use of its low concentrations can still lead to the development of resistance not only to antibiotics. Therefore, it is important to control these characteristics of the population of the gut microbiome piglets. In determining colistin resistance, ZnA supplementation appeared to be the least effective for reducing the resistance. The effect of ZnO and ZnC supplementation could not be determined due to the absence of samples from all sampling days. By determining resistance to aminoglycosides, it was found that bacteria from a single corresponding sample had resistance due to their innate genetic makeup. Thus, it was not obtained through the zinc supplemented feed.
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Riziko kontaminace průsakových vod nežádoucími mikroorganismy při závlahách vyčištěnými odpadními vodami
Růžička, Daniel
This diploma thesis deals with the risk of contamination of seepage water by unde-sirable microorganisms during irrigation by treated waste water. In the literature review, the thesis deals with legislation dealing with irrigation of treated wastewater in the Czech republic, types and quality of wastewater, soil charac-teristics affecting the movement of water in the soil, types and effects of irrigation on the soil environment. In the part "Material and methods" is described the sampling of model soil for the implementation of container experiments and collection of treated wastewater used for irrigation. There is also described the technical design of the container experiment, its preparation and methodology for the determination of the examined organisms in the collected samples of leachate. By determining the concentrations of Escherichia coli and other coliform orga-nisms in the seepage water samples, the natural occurrence of coliform organisms in the soil was determined. During irrigation with treated wastewater from Doubravník, an average loss of 99.0 % of the original E. coli content in the irrigation dose was observed. Meanwhile this value in the second case (treated wastewater obtained from Modřicce), was 87.7 %. Thus, the ability of the soil to change the microbiological quality of irrigation water was confirmed, towards reducing the concentrations of fecal contaminant indica-tor organisms, and thus reducing the risk of contamination of seepage water by patho-gens possibly contained in treated wastewater used for irrigation.
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Testování antimikrobiální aktivity obalových materiálů s rostlinnými extrakty proti E. coli a koliformním bakteriím
Šabršula, Jan
This dissertation deals with evaluation and testing of food packiging materials antimicrobial aktivity that contain plant extracts and help in the fight against Eschericia coli and other coliform bacteria. This dissertation is divided into several parts. The first half of the work contains a literature review publishing about packaging materials containing plant extracts. It is also focused on literature review on the coliform bacteria, especially Escherichia coli genus, describes these microorganisms and their metabolic products, the effects of metabolic products which may negatively affect human health. Another part deals with measures to prevent undesirable microorganisms. The second half of the work has been engaged in actual testing of packaging materials containing plant extracts on relevant model organisms or directly on food. Data, acquired by testing are processed, compared with the figures in the available literatures and are listed at the end of work.
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Sérotypizace patogenních Escherichia coli u selat po odstavu
Valentová, Šárka
One of the most serious threats to pig farming is post-weaning diarrhea which causes huge economic losses worldwide. Diarrhea is often associated with the proliferation of pathogenic Escherichia coli in piglet gut. Some E. coli serotypes are much more likely to be involved in the development of the disease than other serotypes. Antimicrobial zinc oxide is widely used in the current pig industry due to its effective function in alleviating diarrhea and promoting the growth of weaned piglets. However, piglets consume higher levels of zinc, the excreted residues of which raise concerns about environmental pollution. It is therefore important to look for new alternatives that could be effective at lower concentrations. The aim of this thesis is to summarize knowledge about pathogenic E. coli in animals with a focus on piglets after weaning. The research also mentions the intestinal microbiome of pigs and piglets with emphasis on the effect of weaning. Then, E. coli and its virulence factors and serotypes are characterized further on. The thesis then describes infectious diseases caused by pathogenic E. coli and various antimicrobial agents which serve to suppress these diseases. The experimental part includes serotyping of E. coli obtained from piglets after weaning. First, the multiplex-PCR (polymerase chain reaction) method was optimized and then used to determine the occurrence of serotypes O139, O147, O149 and O157. Of the 153 samples tested, the O-serotype was determined in 97 of them. The dominant serotype O149 was detected 56 times. The results were verified by serotyping with commercial antisera and by DNA sequencing of randomly selected PCR products.
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Výskyt patogenních mikroorganismů u microgreens
Kupčíková, Veronika
Microgreens are a newly emerging type of salad crop with characteristics similar to seed sprouts. This thesis is focused on the presence of pathogenic microorganisms in microgreens and possible negative consequences of these pathogens on human health. The theoretical part of this thesis describes the technology used for growing microgreens, microbial risks of microgreens and the characteristics of chosen pathogens, furthermore it looks at the content of health beneficial nutrients in microgreens and the legislation associated with microgreens. The practical part of this thesis includes a statistical evaluation of the levels of pathogens found in the acquired microgreen samples. The quantities of microorganisms, Escherichia coli, coliform bacteria, mold and enterobacteriacea were measured in the samples and the results were compared to previous scientific researches on this topic. The results are also confronted with the current applicable legislation.
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Escherichia coli-induced central nervous system infection and its impact to neurotransmitters' signaling in the host brain.
Lokočová, Gabriela ; Luptáková, Dominika (advisor) ; Krempaská, Katarína (referee)
Dissemination of microbial pathogens to the central nervous system (CNS) is one of the most severe and life-threatening complications of neurological disorders, especially in neonates. Microbial pathogen-induced CNS meningitis and encephalitis develop through several steps of host-pathogen interactions, including a high level of bacteremia (bacterial blood count >103 mL-1 ), mucosal colonization by the pathogen, microbial invasion of the intravascular space, and inoculation into the cerebrospinal fluid (CSF), leading to penetration of CNS barriers and inflammation of meninges and brain parenchyma. Neuroinfectious diseases are associated with acute changes in mental and motor function that are followed by chronic neurological dysfunction that can persist long after the recovery from the infection event. Increased expression of cytokines and chemokines by brain cells and CNS compartment-dependent infiltration of leukocytes and neutrophils modulate brain metabolism and function via an effect on neuronal signaling by neurotransmitters. This work aims to summarize the current knowledge about the CNS infections induced by Escherichia coli and brain region-specific neuromodulatory changes with focus on the glutamatergic, dopaminergic, and serotonergic pathway that may be further involved in host's...
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Interaction of non-thermal plasma at atmospheric pressure (CAPP) with non-pathogenic bacteria
Chobotská, Barbora ; Brázda, Václav (referee) ; Kozáková, Zdenka (advisor)
The subject of this bachelor thesis is the study of decontamination effects of cold atmospheric pressure plasma (CAP) on selected bacteria Escherichia coli and Staphylococcus epidermidis. A non-thermal microwave plasma torch was used. The plasma torch was connected to the software in the computer, which allowed its movement over the treated area. The used power fluctuated between 12–13 W and argon (gas purity 4.6) was chosen as the working gas with a constant flow rate of 5 l/min Inhibition efficacy was observed depending on the type of the selected treatment. The chosen treatment parameters included the effect of speed, direction, and treatment time for both studied bacteria. The aim was to achieve the highest decontamination of the treated area and to determine which of these parameters appeared to be the most significant. No obvious difference (between the treatment directions) was found in the overall decontamination of the treated area for studied bacteria Escherichia coli. The negative effect of speed was only observed for the fastest speed used in the case of gram-positive Staphylococcus epidermidis. The most significant parameter was found to be the treatment time, where a significant decrease in colony growth was observed with increasing treatment time. Furthermore, a repeated treatment was done, where the inoculum was prepared from the already treated bacteria. By this set of experiments, possible development of microbial resistance against the plasma treatment was tested. The results showed that there was no significant increase in the number of colonies even after the repeated treatment. It was also observed that the gram-positive bacteria Staphylococcus epidermidis showed lower decontamination effect evaluated via the number of colonies than the gram-negative bacteria Escherichia coli for all treatment types studied.
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Impact of honey enrichment on its antimicrobial activity by bioactive substances against Escherichia coli
ŠEBESTOVÁ, Lucie
The main aim of this bachelor's thesis is to determine the Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) of both native honeys and honeys enriched with selected essential oils on the growth of Escherichia coli. In the theoretical part of the bachelor's thesis, bacteria Escherichia coli is briefly characterized, including its pathogenic strains and antibiotic resistance. Furthermore, honey is described, including its chemical composition and physiological effects. Additionally, essential oils are generally described, including their antimicrobial properties, along with a brief description of each selected oil. In the methodological part of the bachelor's thesis, procedures for preparing mediums, agar, inoculum, and the determination of their minimum inhibitory and bactericidal concentrations are described. MIC was measured spectrophotometrically in 96 well microtiter plates. MBC was determined by inoculation from the plate onto Mueller-Hinton agar followed by a 24hour incubation. A total of 3 native honeys were tested, which were then enriched with 8 selected essential oils. Essential oils with the addition of dimethyl sulfoxide (DMSO) were also tested. The results of the obtained data are statistically evaluated, graphically presented, and compared with scientific sources.
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