virulence complexity
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Contributions to microbiology, ISSN 1420-9519 vol. 12
VII, 278 s. : il., tab., grafy ; 24 cm
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.
- MeSH
- bakteriální léková rezistence MeSH
- biofilmy růst a vývoj MeSH
- dítě MeSH
- dospělí MeSH
- enzymy sekrece 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
Rinovírusy paria medzi najčastejšie sa vyskytujúcich pôvodcov respiračných ochorení rozličného charakteru od „bežného prechladnutia“ až po klinicky závažné bronchiolitídy či pneumónie u dojčiat a batoliat. Problematika vzťahu rinovírusových infekcií u predisponovaných jedincov, najmä detí v dojčenskom a batolivom veku s následným rizikom rozvoja bronchiálnej astmy bola za posledné dve dekády predmetom mnohých klinických štúdií. Početné zložité a komplexné interakcie rinovírusov s epiteliálnymi bunkami a jednotlivými zložkami imunitného systému ešte nie sú dostatočne a podrobne ozrejmené. Niektoré špecifické patomechanizmy a ich následky, ktoré indukuje vstup a replikácia rinovírusov v bunkách respiračného epitelu, sú už známe. Z klinického pohľadu je vynakladaná čoraz väčšia snaha čo najexaktnejšie identifikovať vonkajšie a vnútorné faktory, ktoré v kontexte opakovaných rinovírusových infekcií predisponujú nositeľa k rekurentným vírusmi indukovaným bronchospazmom a rizikom nadobudnutia astmy. V prvej časti prehľadového príspevku sú rinovírusy analyzované z virologického a epidemiologického hľadiska s prihliadnutím na determinujúce vonkajšie faktory rinovírusových infekcií.
Rhinoviruses are one of the most common causative agents of respiratory diseases from common cold to clinically severe bronchiolitis and pneumonia in infants and toddlers. The relationship of rhinovirus infections in predisposed individuals, especially infants and toddlers, with subsequent risk of bronchial asthma development has been the aim of many clinical studies over the last two decades. The multiple complex and involved interactions of rhinoviruses with epithelial cells and various elements of the immune system have not yet been sufficiently and extensively understood. Some specific pathomechanisms and their consequences induced by the entry and replication of rhinoviruses in respiratory epithelial cells are already known. From a clinical point of view, increasing effort is being devoted to identifying extrinsic and intrinsic factors that, in the context of recurrent rhinovirus infections, predispose the host to recurrent virus-induced bronchospasm and risk of asthma development. In this first part of the review, rhinoviruses are analysed from a virological and epidemiological point of view, with consideration of the determining external factors of rhinovirus infections.
- MeSH
- bronchiální astma * epidemiologie virologie MeSH
- dítě MeSH
- lidé MeSH
- náchylnost k nemoci * mikrobiologie MeSH
- replikace viru fyziologie MeSH
- Rhinovirus * fyziologie klasifikace MeSH
- virulence MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- Publikační typ
- přehledy MeSH
The tetratricopeptide repeat (TPR) structural motif is known to occur in a wide variety of proteins present in prokaryotic and eukaryotic organisms. The TPR motif represents an elegant module for the assembly of various multiprotein complexes, and thus, TPR-containing proteins often play roles in vital cell processes. As the TPR profile is well defined, the complete TPR protein repertoire of a bacterium with a known genomic sequence can be predicted. This provides a tremendous opportunity for investigators to identify new TPR-containing proteins and study them in detail. In the past decade, TPR-containing proteins of bacterial pathogens have been reported to be directly related to virulence-associated functions. In this minireview, we summarize the current knowledge of the TPR-containing proteins involved in virulence mechanisms of bacterial pathogens while highlighting the importance of TPR motifs for the proper functioning of class II chaperones of a type III secretion system in the pathogenesis of Yersinia, Pseudomonas, and Shigella.
This study was aimed to examine the genetic characteristics of 44 Streptococcus suis type 2 (SS2) isolates and the virulence attributes of 23 representative isolates. Multilocus sequence typing revealed five sequence types (ST1, ST7, ST28, ST86, and ST162) with 19 isolates assigned to ST7 (43.2%), 14 to ST1 (31.8%), and 9 to ST28 (20.5%). PCR typing of the pilus gene clusters classified the isolates into three types: A (72.7%), B (22.7%), and N (4.5%). All isolates of pilus types A and N were assigned to the ST1 complex containing ST1, ST7, and ST86, while those of type B belonged to the ST27 complex comprising ST28 and ST162. Only two strains had the putative pathogenicity island 89-kb cluster (89K) and were of type N. The type B strains had a significantly lower adhesion, were more readily killed by macrophage, and had lower virulence to mice than those of types A and N. We conclude that SS2 strains of both ST1 and ST27 complexes, parallel to pilus types A and B, were prevalent in the pig populations in Zhejiang Province, and ST7 and ST1 strains were the predominant genotypes in the diseased pigs with pneumonia.
- MeSH
- bakteriální proteiny genetika metabolismus MeSH
- faktory virulence genetika metabolismus MeSH
- fylogeneze MeSH
- genotyp MeSH
- molekulární sekvence - údaje MeSH
- myši inbrední BALB C MeSH
- myši MeSH
- nemoci prasat mikrobiologie MeSH
- prasata MeSH
- Streptococcus suis klasifikace genetika izolace a purifikace patogenita MeSH
- streptokokové infekce mikrobiologie veterinární MeSH
- virulence MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Čína MeSH
Antibiotic resistance is currently a serious health problem. Since the discovery of new antibiotics no longer seems to be a sufficient tool in the fight against multidrug-resistant infections, adjuvant (combination) therapy is gaining in importance as well as reducing bacterial virulence. Silymarin is a complex of flavonoids and flavonolignans known for its broad spectrum of biological activities, including its ability to modulate drug resistance in cancer. This work aimed to test eleven, optically pure silymarin flavonolignans for their ability to reverse the multidrug resistance phenotype of Staphylococcus aureus and reduce its virulence. Silybin A, 2,3-dehydrosilybin B, and 2,3-dehydrosilybin AB completely reversed antibiotic resistance at concentrations of 20 μM or less. Both 2,3-dehydrosilybin B and AB decreased the antibiotic-induced gene expression of representative efflux pumps belonging to the major facilitator (MFS), multidrug and toxic compound extrusion (MATE), and ATP-binding cassette (ABC) families. 2,3-Dehydrosilybin B also inhibited ethidium bromide accumulation and efflux in a clinical isolate whose NorA and MdeA overproduction was induced by antibiotics. Most of the tested flavonolignans reduced cell-to-cell communication on a tetrahydrofuran-borate (autoinducer-2) basis, with isosilychristin leading the way followed by 2,3-dehydrosilybin A and AB, which halved communication at 10 μM. Anhydrosilychristin was the only compound that reduced communication based on acyl-homoserine lactone (autoinducer 1), with an IC50 of 4.8 μM. Except for isosilychristin and anhydrosilychristin, all of the flavonolignans inhibited S. aureus surface colonization, with 2,3-dehydrosilybin A being the most active (IC50 10.6 μM). In conclusion, the selected flavonolignans, particularly derivatives of 2,3-dehydrosilybin B, 2,3-dehydrosilybin AB, and silybin A are non-toxic modulators of S. aureus multidrug resistance and can decrease the virulence of the bacterium, which deserves further detailed research.
Burkholderia cepacia complex (Bcc) bacteria have gained notoriety as pathogens in cystic fibrosis (CF) because they are difficult to identify and treat, and also have the ability to spread between CF individuals. Of the 17 formally named species within the complex, Burkholderia multivorans and Burkholderia cenocepacia dominate in CF. Multilocus sequence typing has proven to be a very useful tool for tracing the global epidemiology of Bcc bacteria and has shown that B. cenocepacia strains with high transmissibility, such as the ET-12 strain (ST-28) and the Czech strain (ST-32), have spread epidemically within CF populations in Canada and Europe. The majority of research on the molecular pathogenesis of Bcc bacteria has focused on the B. cenocepacia ET-12 epidemic lineage, with gene mutation, genome sequence analysis and, most recently, global gene expression studies shedding considerable light on the virulence and antimicrobial resistance of this pathogen. These studies demonstrate that the ability of B. cenocepacia to acquire foreign DNA (genomic islands, insertion sequences and other mobile elements), regulate gene expression via quorum sensing, compete for iron during infection, and mediate antimicrobial resistance and inflammation via its membrane and surface polysaccharides are key features that underpin the virulence of different strains. With the wealth of molecular knowledge acquired in the last decade on B. cenocepacia strains, we are now in a much better position to develop strategies for the treatment of pathogenic colonization with Bcc and to answer key questions on pathogenesis concerning, for example, the factors that trigger the rapid clinical decline in CF patients.
- MeSH
- bakteriální léková rezistence MeSH
- bakteriální polysacharidy fyziologie MeSH
- Burkholderia cenocepacia klasifikace genetika izolace a purifikace patogenita MeSH
- Burkholderia cepacia komplex klasifikace genetika izolace a purifikace patogenita MeSH
- cystická fibróza genetika mikrobiologie MeSH
- exprese genu MeSH
- infekce bakteriemi rodu Burkholderia komplikace epidemiologie mikrobiologie MeSH
- infekce dýchací soustavy komplikace epidemiologie mikrobiologie MeSH
- lidé MeSH
- molekulární epidemiologie MeSH
- multilokusová sekvenční typizace metody MeSH
- mutace MeSH
- quorum sensing MeSH
- rozptýlené repetitivní sekvence MeSH
- virulence genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Geografické názvy
- Evropa MeSH
- Kanada MeSH
A rather fast and complicated progression of an infection caused by some strains of Staphylococcus aureus could be associated with the expression and co-action of virulence factor complexes in these strains. This study screened the antibiotic susceptibility and prevalence of virulence markers in isolates of meticillin-resistant S. aureus (MRSA) obtained from patients hospitalized at the University Hospital in Olomouc, Czech Republic. A total of 100 isolates was screened for 13 genes encoding extracellular virulence determinants (tst, pvl, eta, etb, sea, seb, sec, sed, see, seg, seh, sei and sej) and for their distribution in sample types. Eighty-nine isolates were positive for at least one of the genes. Genes for etb, pvl, see and seh were not detected in any of the MRSA isolates. No statistically significant differences in the occurrence of the determinants studied among sample types were found.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální proteiny genetika MeSH
- DNA bakterií analýza izolace a purifikace MeSH
- faktory virulence genetika MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- nemocnice univerzitní MeSH
- polymerázová řetězová reakce MeSH
- prevalence MeSH
- pulzní gelová elektroforéza MeSH
- rezistence na methicilin MeSH
- stafylokokové infekce epidemiologie mikrobiologie MeSH
- Staphylococcus aureus genetika izolace a purifikace patogenita účinky léků MeSH
- virulence genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
