Tularemie patří mezi celosvětově rozšířené zoonózy a i přes její relativně nízkou incidenci v našich podmínkách by neměla být v rámci diferenciální diagnostiky opomíjena. V popisované kazuistice bychom chtěli upozornit na klíště jako možný vektor přenosu ulceroglandulární formy tularemie u dětí a současně vyzvednout výhody metody PCR, která může být použita jako časná a spolehlivá metoda detekce obtížně kultivovatelné bakterie Francisella tularensis.

Tularaemia is a widespread zoonosis, which should be considered in differential diagnostics of lymphadenopathy despite of relatively low incidence of the disease. In the presented case we would like to point out a tick bite as a possible way of transmission of an ulceroglandular form of tularaemia in children as well as underline PCR method as an early and reliable form of detection.

• MeSH
• antibakteriální látky MeSH
• ciprofloxacin aplikace a dávkování   terapeutické užití   MeSH
• Francisella tularensis patogenita   MeSH
• lidé MeSH
• lymfadenopatie chirurgie   etiologie   MeSH
• nemoci přenášené klíšťaty diagnóza   farmakoterapie   patologie   MeSH
• obličej abnormality   chirurgie   patologie   MeSH
• předškolní dítě MeSH
• tularemie * diagnóza   farmakoterapie   patologie   MeSH
• zoonózy diagnóza   farmakoterapie   patologie   MeSH
• Check Tag
• lidé MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• kazuistiky MeSH

Bacteria that are highly virulent, expressing high infectivity, and able to survive nebulization, pose great risk to the human population. One of these is Francisella tularensis, the etiological agent of tularemia. F. tularensis is a subject of intense scientific interest due to the fact that vaccines for its immunoprophylaxis in humans are not yet routinely available. One of the substantial obstacles in developing such vaccines is our insufficient knowledge of processes that initiate and regulate the expression of effective protective immunity against intracellular bacteria. Here, we present data documenting the different pattern of cellular behavior occurring in an environment unaffected by microbiota using the model of germ-free mice mono-associated with F. tularensis subsp. holarctica strain LVS in comparison with a classic specific-pathogen-free murine model during early stages of infection.

• MeSH
• bakteriální vakcíny imunologie   MeSH
• cytokiny metabolismus   MeSH
• Francisella tularensis imunologie   patogenita   MeSH
• gnotobiologické modely imunologie   MeSH
• interakce hostitele a patogenu imunologie   MeSH
• mikrobiota MeSH
• modely nemocí na zvířatech MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• organismy bez specifických patogenů imunologie   MeSH
• peritoneum mikrobiologie   patologie   MeSH
• přirozená imunita MeSH
• slezina mikrobiologie   patologie   MeSH
• tularemie imunologie   mikrobiologie   patologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

D-alanyl-D-alanine carboxypeptidase, product of dacD gene in Francisella, belongs to penicillin binding proteins (PBPs) and is involved in remodeling of newly synthetized peptidoglycan. In E. coli, PBPs are synthetized in various growth phases and they are able to substitute each other to a certain extent. The DacD protein was found to be accumulated in fraction enriched in membrane proteins from severely attenuated dsbA deletion mutant strain. It has been presumed that the DsbA is not a virulence factor by itself but that its substrates, whose correct folding and topology are dependent on the DsbA oxidoreductase and/or isomerase activities, are the primary virulence factors. Here we demonstrate that Francisella DacD is required for intracellular replication and virulence in mice. The dacD insertion mutant strain showed higher sensitivity to acidic pH, high temperature and high osmolarity when compared to the wild-type. Eventually, transmission electron microscopy revealed differences in mutant bacteria in both the size and defects in outer membrane underlying its SDS and serum sensitivity. Taken together these results suggest DacD plays an important role in Francisella pathogenicity.

• MeSH
• antibakteriální látky farmakologie   MeSH
• buněčná stěna metabolismus   MeSH
• Francisella tularensis účinky léků   růst a vývoj   patogenita   MeSH
• karboxypeptidasa štěpící D-Ala-D-Ala vazby serinového typu genetika   metabolismus   MeSH
• kultivované buňky MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• peptidoglykan biosyntéza   MeSH
• proteindisulfidisomerasy genetika   MeSH
• proteiny vázající penicilin genetika   metabolismus   MeSH
• transmisní elektronová mikroskopie MeSH
• tularemie mikrobiologie   patologie   MeSH
• virulence genetika   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

The success of pathogens depends on their ability to circumvent immune defences. Francisella tularensis is one of the most infectious bacteria known. The remarkable virulence of Francisella is believed to be due to its capacity to evade or subvert the immune system, but how remains obscure. Here, we show that Francisella triggers but concomitantly inhibits the Toll-like receptor, RIG-I-like receptor, and cytoplasmic DNA pathways. Francisella subverts these pathways at least in part by inhibiting K63-linked polyubiquitination and assembly of TRAF6 and TRAF3 complexes that control the transcriptional responses of pattern recognition receptors. We show that this mode of inhibition requires a functional type VI secretion system and/or the presence of live bacteria in the cytoplasm. The ability of Francisella to enter the cytosol while simultaneously inhibiting multiple pattern recognition receptor pathways may account for the notable capacity of this bacterium to invade and proliferate in the host without evoking a self-limiting innate immune response.

• MeSH
• adaptorové proteiny signální transdukční genetika   MeSH
• adaptorové proteiny vezikulární transportní genetika   MeSH
• faktor 3 asociovaný s receptory TNF metabolismus   MeSH
• faktor 6 asociovaný s receptory TNF metabolismus   MeSH
• Francisella tularensis imunologie   patogenita   MeSH
• imunitní únik imunologie   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• přirozená imunita imunologie   MeSH
• protein MyD88 genetika   MeSH
• receptory rozpoznávající vzory antagonisté a inhibitory   MeSH
• sekreční systém typu VI metabolismus   MeSH
• tularemie imunologie   mikrobiologie   patologie   MeSH
• ubikvitinace imunologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Francisella tularensis the etiological agent of tularaemia is one of the most infectious human pathogen known. Our knowledge about its key virulence factors has increased recently but it still remains a lot to explore. One of the described essential virulence factors is membrane lipoprotein FTS_1067 (nomenclature of F. tularensis subsp. holarctica strain FSC200) with homology to the protein family of disulphide oxidoreductases DsbA. Lipoprotein consists of two different domains: the C-terminal DsbA_Com1-like domain (DSBA-like) and the N-terminal FKBP-type peptidyl-prolyl cis/trans isomerases (FKBP_N-like). To uncover the biological role of these domains, we created bacterial strain with deletion of the DSBA-like domain. This defect in gene coding for lipoprotein FTS_1067 led to high in vivo attenuation associated with the ability to induce host protective immunity. Analyses performed with the truncated recombinant protein showed that the absence of DSBA-like domain revealed the loss of thiol/disulphide oxidoreductase activity and, additionally, confirmed the role of the FKBP_N-like domain in the FTS_1067 oligomerization and chaperone-like function. Finally, we verified that only full-length form of FTS_1067 recombinant protein possesses the isomerase activity. Based on our results, we proposed that for the correct FTS_1067 protein function both domains are needed.

• MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• faktory virulence genetika   metabolismus   MeSH
• Francisella tularensis genetika   růst a vývoj   patogenita   MeSH
• lipoproteiny genetika   metabolismus   MeSH
• membránové proteiny genetika   metabolismus   MeSH
• modely nemocí na zvířatech MeSH
• mutantní proteiny genetika   metabolismus   MeSH
• myši inbrední BALB C MeSH
• sekvenční delece MeSH
• tularemie mikrobiologie   patologie   MeSH
• virulence MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Francisella tularensis is a highly infectious bacterium that causes the potentially lethal disease tularemia. This extremely virulent bacterium is able to replicate in the cytosolic compartments of infected macrophages. To invade macrophages and to cope with their intracellular environment, Francisella requires multiple virulence factors, which are still being identified. Proteins containing tetratricopeptide repeat (TPR)-like domains seem to be promising targets to investigate, since these proteins have been reported to be directly involved in virulence-associated functions of bacterial pathogens. Here, we studied the role of the FTS_0201, FTS_0778, and FTS_1680 genes, which encode putative TPR-like proteins in Francisella tularensis subsp. holarctica FSC200. Mutants defective in protein expression were prepared by TargeTron insertion mutagenesis. We found that the locus FTS_1680 and its ortholog FTT_0166c in the highly virulent Francisella tularensis type A strain SchuS4 are required for proper intracellular replication, full virulence in mice, and heat stress tolerance. Additionally, the FTS_1680-encoded protein was identified as a membrane-associated protein required for full cytopathogenicity in macrophages. Our study thus identifies FTS_1680/FTT_0166c as a new virulence factor in Francisella tularensis.

• MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• cytosol mikrobiologie   MeSH
• faktory virulence genetika   metabolismus   MeSH
• Francisella tularensis genetika   růst a vývoj   fyziologie   MeSH
• genetické lokusy * MeSH
• genový knockout MeSH
• inzerční mutageneze MeSH
• makrofágy mikrobiologie   MeSH
• modely nemocí na zvířatech MeSH
• myši inbrední BALB C MeSH
• tularemie mikrobiologie   patologie   MeSH
• virulence MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: Francisella tularensis is a biological agent exploitable for bioterrorism and biological warfare purposes due to serious pathogenic progression and easy dissemination. Despite intensive research in the past, some adverse consequences remain unclear. One consequence of this pathogen is oxidative stress. AIMS: The aim of this study was to undertake ex vivo assays for monitoring the disease in mice and increase our knowledge of the oxidative stress induced by tularemia. METHODS: The mouse BALB/c model was chosen and the animals were infected by a dose 10(4) CFU of F. tularensis. After five days, the animals were euthanized. Blood immediately processed in plasma, spleen and liver were sampled from the cadavers. Oxidative stress markers, cytokines and histopathological were undertaken. RESULTS: There was a significant link between oxidative stress and tularemia. Particularly elevated levels of malondialdehyde and decreased levels of low molecular weight antioxidants were found in the liver and spleen of tularemia-infected animals. The histopathological findings correlated well with the oxidative stress markers. The liver and spleen were proven to be significantly at risk from the disease and an association between stress and neutrophils in the affected organs was found. The histopathology excluded risk to other organs such as the kidney and or heart. CONCLUSIONS: Oxidative stress plays a significant role in tularemia infection in mice and this was confirmed by the histology.

• MeSH
• antioxidancia metabolismus   MeSH
• cytokiny metabolismus   MeSH
• Francisella tularensis MeSH
• játra metabolismus   patologie   MeSH
• modely nemocí na zvířatech MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• oxidační stres fyziologie   MeSH
• slezina metabolismus   patologie   MeSH
• tularemie metabolismus   patologie   patofyziologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Tacrine is an inhibitor of enzyme acetylcholinesterase (AChE). In the past, it was used for the treatment of cognitive dysfunction during vascular dementia and Alzheimer disease. Some works have concluded that AChE inhibitors can modulate immune response, and for this reason, we decided to investigate the immune response to a model bacterial disease – tularemia – for which both innate and specific immunity are necessary to resolve the disease. We used 64 BALB/c mice divided into eight groups exposed variously to saline, tacrine in a dose of 20.0–500 μg/kg, infection with tularemia and infection with the contemporary application of tacrine. The mice were euthanized three days after the start of the experiment. We proved a significant reduction in the levels of interleukin-6 (IL-6) and interferon gamma (IFN-γ) in a dose response manner in the infected animals in the course of tularemia. Moreover, tacrine caused a significant increase of the bacterial burden in the liver and spleen. We can conclude that tacrine can aggravate tularemia: that it increases the accessibility of acetylcholine and in this way stimulates the cholinergic anti-inflammatory pathway. The results represent a substantial contribution to the field of inflammation control in the nervous system and it is an advancement of the inflammatory therapy issue.

• MeSH
• bakteriální nálož statistika a číselné údaje   MeSH
• cholinesterasové inhibitory farmakologie   škodlivé účinky   terapeutické užití   MeSH
• imunologická odpověď na dávku * MeSH
• interleukin-18 krev   MeSH
• interleukin-6 krev   MeSH
• játra mikrobiologie   MeSH
• modely nemocí na zvířatech MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• přirozená imunita MeSH
• slezina mikrobiologie   MeSH
• studie případů a kontrol MeSH
• takrin * farmakologie   škodlivé účinky   terapeutické užití   MeSH
• tularemie * farmakoterapie   patologie   MeSH
• zánět farmakoterapie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

• MeSH
• hantavirové infekce etiologie   patologie   prevence a kontrola   přenos   MeSH
• hlodavci * parazitologie   růst a vývoj   MeSH
• leptospiróza etiologie   patologie   prevence a kontrola   přenos   MeSH
• lidé MeSH
• mor etiologie   klasifikace   patologie   prevence a kontrola   přenos   MeSH
• přenos infekční nemoci * prevence a kontrola   MeSH
• salmonelóza etiologie   klasifikace   prevence a kontrola   přenos   MeSH
• tularemie etiologie   patologie   prevence a kontrola   přenos   MeSH
• tyfus endemický přenášený blechami etiologie   patologie   prevence a kontrola   přenos   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH

Francisella tularensis is the causative agent of tularemia. It is an intracellular pathogen with the ability to survive within phagosomes and induce pyroptotic cell death. In this study, we attempted to prove whether oxidative imbalance plays a significant role in tularemia pathogenesis. In our experimental model, we subcutaneously infected female BALB/c mice (dose 10(5) CFU of F. tularensis LVS). Liver, spleen, and blood were collected from mice at regular intervals from days 1-15 after infection. The bacterial burden was assessed by a cultivation test. The burden was unchanging from the 2(nd) to 6(th) day after infection. The bacterial burden corresponded to the plasmatic level of IFN-γ, IL-6, and liver malondialdehyde. After the phase of acute bacteraemia and the innate immunity reaction, the levels of reduced glutathione and total low molecular weight antioxidants decreased significantly and the activity of caspase-3 increased in the liver. The level of reduced glutathione decreased to 25% of the original level, and the total level of low molecular weight antioxidants was less than 50% of the initial amount. The demonstrated effects of tularemia-induced pathology had a more extensive impact on the liver than on the spleen.

• MeSH
• antioxidancia analýza   MeSH
• bakteriální nálož MeSH
• Francisella tularensis patogenita   MeSH
• interferon gama krev   MeSH
• interleukin-6 krev   MeSH
• játra mikrobiologie   MeSH
• krev mikrobiologie   MeSH
• malondialdehyd analýza   MeSH
• modely nemocí na zvířatech MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• oxidační stres MeSH
• slezina mikrobiologie   MeSH
• tularemie mikrobiologie   patologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH