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Significance, occurrence and determinants of horizontally transmissible colistin resistance in Gram negative bacteria
Kislíková, Karolína ; Skoumalová, Petra (referee) ; Márová, Ivana (advisor)
Colistin, also known as polymyxin E, is antibiotics active against most of Gram-negative bacteria. In the pas decade, emergency of multidrug-resistant bacteria led to increase of colistin administration as a last resort antibiotic for human infections. The first plasmid-mediated colistin resistance gene mcr-1 was identified in 2015 in animals in China and after first detection, additional mcr genes: mcr-2, mcr-3, mcr-4, mcr-5, mcr-6, mcr-7 a mcr-8 were described throughout the world. The aim of this thesis was to clarify whether there is horizontal transmission colistin resistance encoded by the mcr genes in gram-negative bacteria isolated from the environment, animals and their breeding and food. The mcr-1 gene was detected in 2 strains Escherichia coli isolated from waste water. The mcr-4 gene was detected in 1 strain Shewanella putrefaciens isolate obtained from the lake. The environment is the most important source and way of spreading this type of resistance in the Czech Republic.
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Antimicrobial resistance in clinical isolates of Clostridioides difficile derived from hospitalised patients in the Czech Republic and Slovakia.
Zíková, Jaroslava ; Krůtová, Marcela (advisor) ; Najmanová, Lucie (referee)
Clostridioides difficile is one of the most common pathogens of healthcare-associated colitis (CDI). However, in recent years there has been an increasing number of reported cases in the community. Causative strain characterization allows us to track the occurrence and spread of certain C. difficile types. To update the current CDI epidemiological situation, between October and November 2021, 342 C. difficile isolates or stool samples from CDI patients for culture were sent from 23 Czech (n=200) and 17 Slovak (n=142) hospitals. All C. difficile isolates were characterized by ribotyping and toxin genes detection. From 342 isolates, 52 different ribotyping profiles were identified. The frequent ribotypes detected were 001, 176, 014, 018 and 020. Genes for toxins A and B were found in all isolates. Genes for binary toxins were detected in 43 (21,5 %) Czech isolates and in 117 (82,4 %) Slovak isolates. Further, selected isolates (n=140, 40,9 %) were subjected to whole-genome sequencing (WGS) and antimicrobial susceptibility testing to 17 antibiotics (E-test). Multilocus sequencing typing determined 30 different sequence types from the 39 included ribotypes. All C. difficile isolates were susceptible to vancomycin, tetracycline, amoxicillin, and meropenem. The most frequently detected antimicrobial...
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Detail analysis on antibiotic and heavy-metal resistance genes and horizontal gene transfer traits in anaerobic bacteria
Vancová, Kateřina ; Schwarzerová, Jana (referee) ; Čejková, Darina (advisor)
This thesis deals with a detail analysis on antibiotic and heavy-metal resistance genes and horizontal gene transfer traits in anaerobic bacteria. Antimicrobial resistance (AMR) in bacteria is a growing threat to public health globally. In these bacteria, AMR genes are often associated with mobile genetic elements (MGEs), which promote their mobility, enabling them to rapidly spread throughout a bacterial community. The work describes the horizontal gene transfer, the issue of antimicrobial resistance and the database for the detection of AMR genes and MGEs. After that, the detection and analysis of AMR genes and MGEs in anaerobic bacteria was done. Almost half of them contained at least 1 gene coding for antibiotic or heavy-metal resistance, 112 different genes overall. Then, 66 different MGEs were detected, 4 of which carried 6 different AMR detected genes.
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Detail analysis on antibiotic and heavy-metal resistance genes and horizontal gene transfer traits in anaerobic bacteria
Vancová, Kateřina ; Schwarzerová, Jana (referee) ; Čejková, Darina (advisor)
This thesis deals with a detail analysis on antibiotic and heavy-metal resistance genes and horizontal gene transfer traits in anaerobic bacteria. Antimicrobial resistance (AMR) in bacteria is a growing threat to public health globally. In these bacteria, AMR genes are often associated with mobile genetic elements (MGEs), which promote their mobility, enabling them to rapidly spread throughout a bacterial community. The work describes the horizontal gene transfer, the issue of antimicrobial resistance and the database for the detection of AMR genes and MGEs. After that, the detection and analysis of AMR genes and MGEs in anaerobic bacteria was done. Almost half of them contained at least 1 gene coding for antibiotic or heavy-metal resistance, 112 different genes overall. Then, 66 different MGEs were detected, 4 of which carried 6 different AMR detected genes.
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Isolation of Quorum Sensing Inhibitory compounds from cyanobacteria
MACHO, Markéta
Overuse of antibiotics has led to the development of resistance in many medically relevant human pathogens, posing a threat to human health. The recent decline in the discovery of novel antibiotics together with development of multi-antibiotic resistant strains demands a search of an alternative approach. Anti-virulence therapy poses significantly lower pressure on developing resistance given its focus on disarming the pathogen rather than eradicating it. Advancement in the field of bacterial cell-to-cell communication (Quorum Sensing, QS) and its molecular mechanism regulating the production of virulence factors in many clinically relevant human pathogens led to the discovery of Quorum Sensing inhibitory (QSI) molecules. Cyanobacteria are recognized as a prolific source of natural bioactive compounds with great pharmacological potential. The aim of this study was to screen cyanobacterial extracts for QSI activity in search of potential anti-virulence drugs. 45 cyanobacterial strains were randomly selected from the in-house culture collection of Centre Algatech, extracted, and fractionated to generate 1575 fractions for QSI evaluation. Strains 3, 16, and 113 exhibited the highest inhibitory potential against both used biosensors, E. coli pSB401 and E. coli pSB1075. The obtained results open a future prospect to isolate and elucidate the lead molecule responsible for QSI activity.
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Antimicrobial consumption in children aged 0-14, international comparison
Laštík, Jozef ; Křížová, Eva (advisor)
Antibiotics are nedůležitějším means that the company has in the fight against bacterial infections. The discovery of penicillin by Sir A.Flemingem in 1928 , its isolation Chaine and Floreym in 1940 and subsequent clinical use have meant that until serious or fatal bacterial infectious diseases are today curable . In the following years there have been many more antibiotics or chemotherapeutics , which expands treatment options microbial infections . The high popularity of antibiotics in clinical practice over the course of a few decades taken their toll. Substantial consumption of antimicrobial agents and their misuse has led to the emergence of bacterial resistance with which the discovery of antibiotics planned. Adverse the result is a reduced capacity in the selection of antibiotic therapy in the causal infection. This poses a huge risk to the current population , but especially for the next generation . It may even occur to the fact that the antibiotics used today lost due to bacterial resistance efficiency, and we will not be able to fight against bacteria . One of the branches of medicine where there permanently increased consumption of antibiotics , pediatrics . Children have limited immune mechanisms , and therefore constitute a population that is more susceptible to infections. Most often ,...
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A comparative analysis of the isolates of Clostridioides difficile derived from different sources.
Eretová, Veronika ; Krůtová, Marcela (advisor) ; Ježek, Petr (referee)
Clostridioides difficile infections (CDI) are generally perceived as healtcare associated infections. However, there has been recently reported an increase of CDI incidence in the community. The occurrence of C. difficile has been described also in animals, food and the environment water and soil. The aim of this thesis was to characterize C. difficile isolates derived from different sources using molecular methods. The results were discussed with available data from Czech human C. difficile isolates. A total of 135 C. difficile isolates from the following sources were analyzed: pigs n = 57, calves n = 44, horses n = 18, water n = 15 and hedgehog. Using PCR ribotyping, 22 distinct ribotyping profiles were identified, the most frequently detected ribotypes were: 033, 011, 126, 078. Both toxigenic and non-toxigenic ribotypes were detected, including binary toxin-producing strains. The most frequently detected antimicrobial resistances were to ciprofloxacin, clindamycin, and erythromycin. All ribotypes and sequence types identified in the C. difficile isolates from animals and the environment, has been found also in C. difficile isolates from humans which confirms the role of animals and the environment as a source for C. difficile. However, no epidemic ribotype 001 and 176 that dominate the current...
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Significance, occurrence and determinants of horizontally transmissible colistin resistance in Gram negative bacteria
Kislíková, Karolína ; Skoumalová, Petra (referee) ; Márová, Ivana (advisor)
Colistin, also known as polymyxin E, is antibiotics active against most of Gram-negative bacteria. In the pas decade, emergency of multidrug-resistant bacteria led to increase of colistin administration as a last resort antibiotic for human infections. The first plasmid-mediated colistin resistance gene mcr-1 was identified in 2015 in animals in China and after first detection, additional mcr genes: mcr-2, mcr-3, mcr-4, mcr-5, mcr-6, mcr-7 a mcr-8 were described throughout the world. The aim of this thesis was to clarify whether there is horizontal transmission colistin resistance encoded by the mcr genes in gram-negative bacteria isolated from the environment, animals and their breeding and food. The mcr-1 gene was detected in 2 strains Escherichia coli isolated from waste water. The mcr-4 gene was detected in 1 strain Shewanella putrefaciens isolate obtained from the lake. The environment is the most important source and way of spreading this type of resistance in the Czech Republic.
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Antimicrobial consumption in children aged 0-14, international comparison
Laštík, Jozef ; Křížová, Eva (advisor)
Antibiotics are nedůležitějším means that the company has in the fight against bacterial infections. The discovery of penicillin by Sir A.Flemingem in 1928 , its isolation Chaine and Floreym in 1940 and subsequent clinical use have meant that until serious or fatal bacterial infectious diseases are today curable . In the following years there have been many more antibiotics or chemotherapeutics , which expands treatment options microbial infections . The high popularity of antibiotics in clinical practice over the course of a few decades taken their toll. Substantial consumption of antimicrobial agents and their misuse has led to the emergence of bacterial resistance with which the discovery of antibiotics planned. Adverse the result is a reduced capacity in the selection of antibiotic therapy in the causal infection. This poses a huge risk to the current population , but especially for the next generation . It may even occur to the fact that the antibiotics used today lost due to bacterial resistance efficiency, and we will not be able to fight against bacteria . One of the branches of medicine where there permanently increased consumption of antibiotics , pediatrics . Children have limited immune mechanisms , and therefore constitute a population that is more susceptible to infections. Most often ,...
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