Infection with Borrelia burgdorferi often triggers pathophysiologic perturbations that are further augmented by the inflammatory responses of the host, resulting in the severe clinical conditions of Lyme disease. While our apprehension of the spatial and temporal integration of the virulence determinants during the enzootic cycle of B. burgdorferi is constantly being improved, there is still much to be discovered. Many of the novel virulence strategies discussed in this review are undetermined. Lyme disease spirochaetes must surmount numerous molecular and mechanical obstacles in order to establish a disseminated infection in a vertebrate host. These barriers include borrelial relocation from the midgut of the feeding tick to its body cavity and further to the salivary glands, deposition to the skin, haematogenous dissemination, extravasation from blood circulation system, evasion of the host immune responses, localization to protective niches, and establishment of local as well as distal infection in multiple tissues and organs. Here, the various well-defined but also possible novel strategies and virulence mechanisms used by B. burgdorferi to evade obstacles laid out by the tick vector and usually the mammalian host during colonization and infection are reviewed.

• Klíčová slova
• Borrelia burgdorferi, Lyme disease, clinical manifestations, pathogenicity, tick-borne disease, virulence determinants,
• MeSH
• Borrelia burgdorferi * genetika   MeSH
• faktory virulence MeSH
• lidé MeSH
• lymeská nemoc * MeSH
• savci MeSH
• virulence MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• faktory virulence MeSH

Catalase is one of the most abundant enzymes on Earth. It decomposes hydrogen peroxide, thus protecting cells from dangerous reactive oxygen species. The catalase-encoding gene is conspicuously absent from the genome of most representatives of the family Trypanosomatidae. Here, we expressed this protein from the Leishmania mexicana Β-TUBULIN locus using a novel bicistronic expression system, which relies on the 2A peptide of Teschovirus A. We demonstrated that catalase-expressing parasites are severely compromised in their ability to develop in insects, to be transmitted and to infect mice, and to cause clinical manifestation in their mammalian host. Taken together, our data support the hypothesis that the presence of catalase is not compatible with the dixenous life cycle of Leishmania, resulting in loss of this gene from the genome during the evolution of these parasites.

• Klíčová slova
• Leishmania, catalase, dixeny, evolution, virulence,
• MeSH
• faktory virulence genetika   metabolismus   MeSH
• katalasa genetika   metabolismus   MeSH
• kultivované buňky MeSH
• Leishmania mexicana genetika   růst a vývoj   patogenita   MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• protozoální proteiny genetika   MeSH
• Psychodidae parazitologie   MeSH
• stadia vývoje genetika   MeSH
• Teschovirus genetika   MeSH
• virulence MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• faktory virulence MeSH
• katalasa MeSH
• protozoální proteiny MeSH

BACKGROUND: Bacteria of the genus Enterococcus are a normal part of the intestinal microflora but also important nosocomial pathogens. An alarming fact is increasing resistance to antimicrobial agents such as vancomycin (VRE). Enterococci frequently produce numerous virulence factors, e.g. gelatinase, surface protein, adhesins and sex pheromones. Their genes, with respect to vancomycin resistance, are studied. MATERIAL AND METHODS: In 108 isolates obtained from various clinical samples (except for stools) taken from patients in the University Hospital Olomouc and divided into VRE (n = 54) and control, vancomycin-susceptible (n = 54) groups, the prevalence of genes for gelatinase (gelE), surface protein (esp) and sex pheromones (cpd, cob and ccf) was investigated. For genetic detection, real-time PCR was used. RESULTS: In the control group of vancomycin-susceptible enterococci, only six isolates (11.1 %) showed none of the studied virulence factors. The most prevalent gene was ccf (77.7 %, n = 42), followed by cpd in 66.6 % (36), gelE in 55.5 % (30), esp in 46.3 % (25) and cob in 38.9 % (21). In the VRE group, 17 isolates (31.5%) contained none of the studied genes. More prevalent was esp in 62.9 % (34), substantially less frequent were cpd in 5.6 % (3), cob in 5.6 % (3), ccf in 5.6 % (3) and gelE in 3.7 % (2). CONCLUSIONS: In VRE a smaller occurence, i.e. four out of the five studied virulence factors, were detected. The lower prevalence of genes for virulence factors was probably due to their species representation (substantially higher frequency of Enterococcus faecium in which these genes are mostly much less prevalent).

• MeSH
• Enterococcus účinky léků   genetika   metabolismus   MeSH
• faktory virulence genetika   MeSH
• lidé MeSH
• rezistence na vankomycin * genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• Názvy látek
• faktory virulence MeSH

The nucleoid-associated HU proteins are small abundant DNA-binding proteins in bacterial cell which play an important role in the initiation of DNA replication, cell division, SOS response, control of gene expression and recombination. HU proteins bind to double stranded DNA non-specifically, but they exhibit high affinity to abnormal DNA structures as four-way junctions, gaps or nicks, which are generated during DNA damage. In many pathogens HU proteins regulate expression of genes involved in metabolism and virulence. Here, we show that the Francisella tularensis subsp. holarctica gene locus FTS_0886 codes for functional HU protein which is essential for full Francisella virulence and its resistance to oxidative stress. Further, our results demonstrate that the recombinant FtHU protein binds to double stranded DNA and protects it against free hydroxyl radicals generated via Fenton's reaction. Eventually, using an iTRAQ approach we identified proteins levels of which are affected by the deletion of hupB, among them for example Francisella pathogenicity island (FPI) proteins. The pleiotropic role of HU protein classifies it as a potential target for the development of therapeutics against tularemia.

• Klíčová slova
• DNA binding protein, FPI, Francisella, HU protein, nucleoid-associated protein, virulence,
• MeSH
• bakteriální proteiny metabolismus   MeSH
• delece genu MeSH
• DNA vazebné proteiny metabolismus   MeSH
• DNA metabolismus   MeSH
• faktory virulence metabolismus   MeSH
• Francisella tularensis růst a vývoj   fyziologie   MeSH
• fyziologický stres MeSH
• oxidační stres MeSH
• stanovení celkové genové exprese MeSH
• vazba proteinů MeSH
• virulence MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální proteiny MeSH
• DNA vazebné proteiny MeSH
• DNA MeSH
• faktory virulence MeSH
• histone-like protein HU, bacteria MeSH Prohlížeč

Copper plays a fundamental role in aerobic metabolism, but its role is double-edged, given its toxicity. Our understanding of copper metabolism in parasites remains rudimentary, despite its significance in virulence. Here we discuss how parasitic protists control copper homeostasis and show the potential key players identified by our bioinformatic analysis.

• Klíčová slova
• bioinformatic analysis, copper, parasitic protists,
• MeSH
• Eukaryota MeSH
• faktory virulence metabolismus   MeSH
• měď metabolismus   MeSH
• paraziti * metabolismus   MeSH
• virulence MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• faktory virulence MeSH
• měď MeSH

American foulbrood is a quarantine disease of the honeybee Apis mellifera L. in many countries and contributes greatly to colony losses. We performed a label-free proteomics study of exoprotein fractions produced in vitro by Paenibacillus larvae reference strains of the ERIC I-IV genotypes. A quantitative comparison was performed of previous studied protein-based virulence factors and many newly identified putative virulence factors. Among the multiple proteases identified, key virulence factors included the microbial collagenase ColA and immune inhibitor A (InhA, an analog of the Bacillus thuringiensis protein InhA). Both of these virulence factors were detected in ERICs II-IV but were absent from ERIC I. Furthermore, the different S-layer proteins and polysaccharide deacetylases prevailed in ERICs II-IV. Thus, the expression patterns of these virulence factors corresponded with the different speeds at which honeybee larvae are known to be killed by ERICs II-IV compared to ERIC I. In addition, putative novel toxin-like proteins were identified, including vegetative insecticidal protein Vip1, a mosquitocidal toxin, and epsilon-toxin type B, which exhibit similarity to homologs present in Bacillus thuringiensis or Lysinibacillus sphaericus. Furthermore, a putative bacteriocin similar to Lactococcin 972 was identified in all assayed genotypes. It appears that P. larvae shares virulence factors similar to those of the Bacillus cereus group. Overall, the results provide novel information regarding P. larvae virulence potential, and a comprehensive exoprotein comparison of all four ERICs was performed for the first time. The identification of novel virulence factors can explain differences in the virulence of isolates.

• Klíčová slova
• ADP-ribosylating toxin, American foulbrood, Apis mellifera, Bacillus thuringiensis, S-layer protein, bacteriocin, immune inhibitor A, microbial collagenase ColA, mosquitocidal toxin, polysaccharide deacetylase,
• MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• faktory virulence genetika   metabolismus   MeSH
• genotyp MeSH
• Paenibacillus larvae genetika   MeSH
• proteomika * MeSH
• včely mikrobiologie   MeSH
• virulence MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální proteiny MeSH
• faktory virulence MeSH

Fungal infections are currently a serious health concern. Life-threatening conditions that occur mainly in immunocompromised patients are largely caused by representatives of the genus Candida. The most common causative agent is the yeast Candida albicans, but in recent years there has been a significant shift towards Candida glabrata and other so-called non-albicans Candida yeasts (e.g. Candida tropicalis or Candida parapsilosis). Invasive infections caused by the multidrug-resistant yeast Candida auris are associated with high mortality. There are several differences between C. glabrata and other causative agents of candidiasis in biological characteristics and virulence factors. The innate increased resistance to azoles along with the ability to rapidly acquire resistance to other groups of antifungal agents is a dangerous combination which makes it difficult to manage Candida infections. A better understanding of the virulence factors and mechanisms of resistance to antifungal agents can benefit the management of Candida infections. Equally important is the search for new target sites for antifungal therapy. The present work briefly summarizes the existing knowledge in this area.

• Klíčová slova
• Candida glabrata, antifungal resistance, biofilm, ergosterol, virulence,
• MeSH
• antifungální látky farmakologie   terapeutické užití   MeSH
• Candida glabrata * MeSH
• Candida MeSH
• faktory virulence MeSH
• fungální léková rezistence MeSH
• kandidóza * farmakoterapie   mikrobiologie   MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• virulence MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antifungální látky MeSH
• faktory virulence MeSH

The nosocomial pathogen Pseudomonas aeruginosa is equipped with a large arsenal of cell-associated and secreted virulence factors which enhance its invasive potential. The complex relationships among virulence determinants have hitherto not been fully elucidated. In the present study, 175 catheter-related isolates were observed for the presence of selected virulence factors, namely extracellular enzymes and siderophore production, biofilm formation, resistance to antibiotics, and motility. A high percentage of the strains produced most of the tested virulence factors. A positive correlation was identified between the production of several exoproducts, and also between the formation of both types of biofilm. An opposite trend was observed between the two types of biofilm and the production of siderophores. Whereas the relationship between the submerged biofilm production (i.e. the biofilm formed on the solid surface below the water level) and the siderophore secretion was negative, the production of air-liquid interface (A-L) biofilm (i.e. the biofilm floating on the surface of the cultivation medium) and the siderophore secretion were positively correlated. All correlations were statistically significant at the level P = 0.05 with the correlation coefficient γ ≥ 0.50. Our results suggest that: (1) the co-production of the lytic enzymes and siderophores can play an important role in the pathogenesis of the catheter-related infections and should be taken into account when the virulence potential is assessed; (2) biofilm-positive strains are capable of forming both submerged and non-attached A-L biofilms; and (3) the different micro-environment in the submerged biofilm and A-L biofilm layers have opposite consequences for the production of other virulence factors.

• Klíčová slova
• Pseudomonas aeruginosa, antibiotic resistance, biofilm, blood stream, urinary tract, virulence factors,
• MeSH
• bakteriální léková rezistence MeSH
• biofilmy růst a vývoj   MeSH
• dítě MeSH
• dospělí MeSH
• enzymy metabolismus   MeSH
• faktory virulence analýza   genetika   MeSH
• katétrové infekce mikrobiologie   MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• lokomoce MeSH
• mladiství MeSH
• mladý dospělý MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• pseudomonádové infekce mikrobiologie   MeSH
• Pseudomonas aeruginosa genetika   izolace a purifikace   patogenita   fyziologie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• siderofory metabolismus   MeSH
• virulence MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• enzymy MeSH
• faktory virulence MeSH
• siderofory MeSH

Healthcare quality improvement brings about an increasing number of invasive diagnostic and therapeutic procedures and thus also an increasing number of high-risk patients prone to hospital infections. Pseudomonas aeruginosa is one of the most commonly isolated nosocomial species and the treatment of the infection is often long and problematic, with frequent recurrences. The pathogenesis of Pseudomonas infection is associated with a range of virulence factors. In the present study, 93 catheter isolates of Pseudomonas aeruginosa were screened for the biofilm formation, motility and secretion of selected extracellular products. A high rate of the strains tested were producers of hemolysins, LasB elastase, and pyoverdines (> 70%). The biofilm formation was detected in 80% of isolates and formation of aerated biofilm was present in 90% of isolates with a positive correlation found between the two types of biofilm formation (p = 0.00583; gamma = 0.551). All strains showed swarming motility, 95% of strains showed swimming motility, and 75% of strains showed twitching motility. Among the virulence factors studied, only pyocyanin and pyochelin were produced by a lower proportion of isolates (< 25%). A positive correlation was seen between the production of some extracellular molecules (pyochelin and pyocyanin, pyocyanin and LasB elastase, and LasB elastase and haemolysins), between biofilm formation and formation of aerated biofilm, and between formation of aerated biofilm and pigments (pyoverdine and pyocyanin) production. On the other hand, a negative correlation was found between biofilm production and LasB elastase production and between the production of biofilm under immersion and pigments (pyoverdine and pyocyanin) production. All correlations are significant at the level p = 0.05, with the correlation coefficient gamma > 0.50.

• MeSH
• bakteriální proteiny analýza   MeSH
• biofilmy MeSH
• faktory virulence analýza   MeSH
• hemolyziny analýza   MeSH
• katétrové infekce mikrobiologie   MeSH
• lidé MeSH
• metaloendopeptidasy analýza   MeSH
• oligopeptidy analýza   MeSH
• pseudomonádové infekce mikrobiologie   MeSH
• Pseudomonas aeruginosa izolace a purifikace   patogenita   fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• bakteriální proteiny MeSH
• faktory virulence MeSH
• hemolyziny MeSH
• metaloendopeptidasy MeSH
• oligopeptidy MeSH
• pseudolysin, Pseudomonas aeruginosa MeSH Prohlížeč
• pyoverdin MeSH Prohlížeč

Nosocomial infections associated with biofilm formation have been a serious problem in recent years. Up to 32 % of them are urinary tract infections in patients with long-dwelling catheters. Catheters represent an ideal surface for bacterial adhesion, facilitating easier colonization of the urinary tract. Important pathogens causing these infections are bacteria of the genus Proteus that colonize catheters not only by biofilm formation but also using other virulence factors. Those were developed for survival in the host organism and are also used by bacteria to infect the host or fight the defence mechanisms. The study focused on the following selected virulence factors: swimming, swarming and twitching motility, swarming motility across various types of urinary catheters, biofilm formation in various media, formation of biofilm on catheters, haemolysin and urease production. A total of 102 strains isolated from urinary catheters and 50 strains isolated from stools were analyzed. In twitching motility, a difference between strains isolated from catheters and stools was statistically significant (p = 0.012). In swimming and swarming motility, the difference was not significant (p = 0.074 and p = 0.809, respectively). In motility across various catheter types, a statistically significant difference was found in strains isolated from both catheters and stools (p « 0.01 in both cases). For biofilm formation analyses, BHI and BHI with 4 % glucose were used. In BHI, biofilm was produced by all strains, with 65% of catheter strains and 88 % of strains from stools being strong producers. Similarly, all strains produced biofilm in BHI with 4 % glucose, with strong producers in 94 % and 92 % of strains isolated from catheters and stools, respectively. In formation of biofilm on catheters, there was a statistical difference between strains from catheters and stools (p = 0.00008). All strains isolated from both catheters and stools produced urease; no difference in urease production was statistically significant (p = 0.653). On agar with washed sheep erythrocytes, haemolysin production was not detected in any of the isolated strains. The quantitative method using horse erythrocytes revealed haemolysis production in three strains isolated from catheters.

• MeSH
• biofilmy MeSH
• faktory virulence analýza   MeSH
• infekce močového ústrojí mikrobiologie   MeSH
• infekce spojené se zdravotní péčí mikrobiologie   MeSH
• katetrizace močového měchýře škodlivé účinky   MeSH
• kontaminace zdravotnického vybavení MeSH
• lidé MeSH
• Proteus mirabilis izolace a purifikace   patogenita   fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• faktory virulence MeSH