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Motility and virulence of bacterial pathogens in patients with cystic fibrosis
Benešová, Nikol ; Melter, Oto (advisor) ; Smělíková, Eva (referee)
Cystic fibrosis is an autosomal recessive disease that mainly effects the Europoid race. The disease is caused by a mutation in the cystic fibrosis transmembrane conductance regulator gene. This gene encodes the formation of chloride channel proteins. The disease leads to the formation of highly viscous secretions from the exocrine glands. The most commonly affected organ is the lung, which accumulates mucus and bacteria. Bacteria that colonize the lungs of patients with cystic fibrosis are exposed to many stress factors such as large amounts of mucus, oxidative stress, antibiotics and immune system of the host. That leads to the selection of mutants that are better adapted to the environment of the lungs. In acute infection, one of the important virulence factors for bacteria is their motility. Motility is provided by flagella and allows the bacterium to move to sites with higher nutrient content and to colonise different parts of the lung. In chronic infection, we can see changes in the genotype and phenotype of bacteria. Nonmotile mutants are selected because they activate the immune system less than motile bacteria, that helps in the persistence of bacteria in the lungs. Chronic infections lead to a higher mortality rate. The aim of this bachelor's thesis is to compare the motility of bacteria...
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Molecular identification, typing and adaptation of Achromobacter spp. during the course of chronic infection
Učíková, Barbora ; Dřevínek, Pavel (advisor) ; Nemec, Alexandr (referee)
Achromobacter spp. is an emerging pathogen, especially in chronic respiratory infections in patients with cystic fibrosis. MALDI-TOF mass spectrometry provides reliable identification only at the genus level. The nrdA gene sequence is used for species identification of representatives. Clonality studies using multilocus sequence typing can determine whether a patient is still infected with the same clone or whether reinfection with a new strain occurs over time. Time-collected isolates of Achromobacter spp. from patients with cystic fibrosis were included in our study. Patients were divided into three groups according to the time interval between collections. In the first group, the external interval between collections was approximately 10 years, in the second group 7 to 12 months, and the remaining group consisted of single isolates. In the course of chronic infection, Achromobacter spp. adapt to the exposed antibiotics and to the host. Isolates sampled at an interval of 10 years showed a higher number of mutations than isolates with a sampling interval of up to one year. During chronic infection, loss of motility occurs, which we demonstrated phenotypically at the level of motility, reduction in flagella number and changes in flagellar genes. Increased resistance was observed in some isolates by...
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