pathogen isolates Dotaz Zobrazit nápovědu
Spomedzi 162 humánnych izolátov rodu Trichosporon autorka podľa „kľúčových“ znakov (Guého etal. 1992, 1994) identifikovala ako dominantné T. mucoides (41 %) a T. asahii (33 %). Druhy T. inkin,T. ovoides a aj nepatogénny T. pullulans boli v sledovanom súbore zriedkavé. Do pôvodne najčastejšie uvádzaného druhu T. cutaneum patrilo menej než 10 % z celkového počtu izolátov. Variabilnosť fyziologických a biochemických znakov nedovolila presné zaradenie 5 % izolovaných kmeňovTrichosporon. Diskovou difúznou metódou sa potvrdila rezistencia testovaných kmeňov voči 5-fluorocytozínu a inhibícia polyénovými a azolovými antimykotikami.
Among 162 human isolates of Trichosporon the author isolated according to „crucial“ signs (Guéhoet al. 1992, 1994) the following as dominant: T. mucoides (41%) and T. asahii (33%), T. inkin, T. ovoidesand others as well as non-pathogenic T. pullulans were rare in their investigation. To the originallymost frequently reported type T. cutaneum belonged less than 10% of the total number of isolates.The variability of physiological and biological signs did not make classification of 5% isolatedTrichosporon strains possible. The disc diffusion method confirmed resistance of the tested strainsto 5-fluorocytosine, and inhibition by polyenie and azole antimycotics.
V súbore 487 klinických izolátov Salmonella Enteritidis sa okrem fágotypu hodnotili markery virulencie – hydrofóbnosť bunkového povrchu baktérií, motilita, tvorba biofilmu ako aj prítomnosť sérovar–špecifického 60kb plazmidu virulencie. Najčastejší fágotyp bol PT8 (48,3%), a ďalšie fágotypy boli PT13a (7,2%), PT15 (6,4%), PT4 (4,5%). 31 kmeňov (6,4%) bolo netypovateľných. Na základe získaných výsledkov z hodnotenia jednotlivých markerov virulencie, 128 kmeňov (26,3%) bolo hydrofóbnych v teste adherencie na xylén, pričom najväčší počet kmeňov s vysokou hydrofóbnosťou sa zistil medzi fágotypmi PT9a (84,6%), PT25 (81,8%), PT15 (54,8%) a PT8 (23,4%). Motilita ≥ 50 mm bola u 294 (60,4%) kmeňov a viditeľný biofilm rôzneho stupňa v skúmavkovom teste tvorilo 448 kmeňov (91,9%). Schopnosť tvorby biofilmu in vitro poukazuje na vysoký virulenčný potenciál študovaných kmeňov. Sérovar-špecifický 60 kb plazmid virulencie obsahovalo 467 (95,9%) kmeňov. Jasná korelácia medzi fágotypom a jednotlivými markermi virulencie v študovanom súbore kmeňov sa nezistila. Získané in vitro výsledky naznačujú flexibilitu Salmonella Enteritidis v infikovaní hostiteľa.
A set of 487 clinical isolates of Salmonella Enteritidis were phage typed and analyzed for virulence markers, i.e. bacterial cell surface hydrophobicity, motility, biofilm formation and the presence of a 60 kb serovar-specific virulence plasmid. The most frequent phage type was PT8 (48.3%), followed by PT13a (7.2%), PT15 (6.4%), and PT4 (4.5%). Thirty-one (6.4%) strains were non-typeable. As many as 128 (26.3%) strains showed hydrophobicity in the hydrocarbon xylene adherence assay, with the highest percentages of highly hydrophobic strains being found among the following phage types: PT9a (84.6%), PT25 (81.8%), PT15 (54.8%) and PT8 (23.4%). Motility ≥ 50 mm was observed in 294 (60.4%) strains and visible biofilm was formed in the test tube assay in different degrees by 448 (91.9%) strains. The capacity of in vitro biofilm formation is indicative of a high virulence potential of the study strains. The 60 kb serovar-specific virulence plasmid was present in 467 (95.9%) strains. Clear correlation between phage types and particular virulence markers was not revealed in the study set of strains. The obtained in vitro results are suggestive of flexibility of Salmonella Enteritidis in infecting the host.
- MeSH
- biologické markery analýza MeSH
- fagotypizace klasifikace metody statistika a číselné údaje MeSH
- faktory virulence analýza izolace a purifikace klasifikace MeSH
- finanční podpora výzkumu jako téma MeSH
- plazmidy analýza imunologie izolace a purifikace MeSH
- Salmonella enteritidis izolace a purifikace klasifikace patogenita MeSH
- Publikační typ
- srovnávací studie MeSH
- Geografické názvy
- Slovenská republika MeSH
Classical virulence analysis is based on discovering virulence phenotypes of isolates with regard to a composition of resistance genes in a differential set of host genotypes. With such a vision, virulence phenotypes are usually treated in a genetic manner as one of two possible alleles, either virulence or avirulence in a binary locus. Therefore, population genetics metrics and methods have become prevailing tools for analyzing virulence data at multiple loci. However, a basis for resolving binary virulence phenotypes is infection type (IT) data of host-pathogen interaction that express functional traits of each specific isolate in a given situation (particular host, environmental conditions, cultivation practice, and so on). IT is determined by symptoms and signs observed (e.g., lesion type, lesion size, coverage of leaf or leaf segments by mycelium, spore production and so on), and assessed by IT scores at a generally accepted scale for each plant-pathogen system. Thus, multiple IT profiles of isolates are obtained and can be subjected to analysis of functional variation within and among operational units of a pathogen. Such an approach may allow better utilization of the information available in the raw data, and reveal a functional (e.g., environmental) component of pathogen variation in addition to the genetic one. New methods for measuring functional variation of plant-pathogen interaction with IT data were developed. The methods need an appropriate assessment scale and expert estimations of dissimilarity between IT scores for each plant-pathogen system (an example is presented). Analyses of a few data sets at different hierarchical levels demonstrated discrepancies in results obtained with IT phenotypes versus binary virulence phenotypes. The ability to measure functional IT-based variation offers promise as an effective tool in the study of epidemics caused by plant pathogens.
Aphanomyces astaci, the causal agent of the crayfish plague, has recently been confirmed to infect also freshwater-inhabiting crabs. We experimentally tested the resistance of freshwater shrimps, another important decapod group inhabiting freshwaters, to this pathogen. We exposed individuals of two Asian shrimp species, Macrobrachium dayanum and Neocaridina davidi, to zoospores of the pathogen strain isolated from Procambarus clarkii, a known A. astaci carrier likely to get into contact with shrimps. The shrimps were kept in separate vessels up to seven weeks; exuviae and randomly chosen individuals were sampled throughout the experiment. Shrimp bodies and exuviae were tested for A. astaci presence by a species-specific quantitative PCR. The results were compared with amounts of A. astaci DNA in an inert substrate to distinguish potential pathogen growth in live specimens from persisting spores or environmental DNA attached to their surface. In contrast to susceptible crayfish Astacus astacus, we did not observe mortality of shrimps. The amount of detected pathogen DNA was decreasing steadily in the inert substrate, but it was still detectable several weeks after zoospore addition, which should be considered in studies relying on molecular detection of A. astaci. Probably due to moulting, the amount of A. astaci DNA was decreasing in N. davidi even faster than in the inert substrate. In contrast, high pathogen DNA levels were detected in some non-moulting individuals of M. dayanum, suggesting that A. astaci growth may be possible in tissues of this species. Further experiments are needed to test for the potential of long-term A. astaci persistence in freshwater shrimp populations.
- MeSH
- Aphanomyces genetika fyziologie MeSH
- Decapoda (Crustacea) genetika mikrobiologie MeSH
- interakce hostitele a patogenu * MeSH
- odolnost vůči nemocem genetika MeSH
- Palaemonidae genetika mikrobiologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The psychrophilic (cold-loving) fungus Pseudogymnoascus destructans was discovered more than a decade ago to be the pathogen responsible for white-nose syndrome, an emerging disease of North American bats causing unprecedented population declines. The same species of fungus is found in Europe but without associated mortality in bats. We found P. destructans was infected with a mycovirus [named Pseudogymnoascus destructans partitivirus 1 (PdPV-1)]. The virus is bipartite, containing two double-stranded RNA (dsRNA) segments designated as dsRNA1 and dsRNA2. The cDNA sequences revealed that dsRNA1 dsRNA is 1,683 bp in length with an open reading frame (ORF) that encodes 539 amino acids (molecular mass of 62.7 kDa); dsRNA2 dsRNA is 1,524 bp in length with an ORF that encodes 434 amino acids (molecular mass of 46.9 kDa). The dsRNA1 ORF contains motifs representative of RNA-dependent RNA polymerase (RdRp), whereas the dsRNA2 ORF sequence showed homology with the putative capsid proteins (CPs) of mycoviruses. Phylogenetic analyses with PdPV-1 RdRp and CP sequences indicated that both segments constitute the genome of a novel virus in the family Partitiviridae. The purified virions were isometric with an estimated diameter of 33 nm. Reverse transcription PCR (RT-PCR) and sequencing revealed that all US isolates and a subset of Czech Republic isolates of P. destructans were infected with PdPV-1. However, PdPV-1 appears to be not widely dispersed in the fungal genus Pseudogymnoascus, as non-pathogenic fungi P. appendiculatus (1 isolate) and P. roseus (6 isolates) tested negative. P. destructans PdPV-1 could be a valuable tool to investigate fungal biogeography and the host-pathogen interactions in bat WNS.
- MeSH
- Ascomycota izolace a purifikace virologie MeSH
- Chiroptera mikrobiologie MeSH
- dvouvláknová RNA genetika izolace a purifikace MeSH
- fylogeneze MeSH
- mykoviry genetika fyziologie ultrastruktura MeSH
- RNA virová genetika izolace a purifikace MeSH
- sekvence aminokyselin MeSH
- sekvence nukleotidů MeSH
- virové proteiny chemie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Geografické názvy
- Česká republika MeSH
- Spojené státy americké MeSH
Anticipating how epidemics will spread across landscapes requires understanding host dispersal events that are notoriously difficult to measure. Here, we contrast host and virus genetic signatures to resolve the spatiotemporal dynamics underlying geographic expansions of vampire bat rabies virus (VBRV) in Peru. Phylogenetic analysis revealed recent viral spread between populations that, according to extreme geographic structure in maternally inherited host mitochondrial DNA, appeared completely isolated. In contrast, greater population connectivity in biparentally inherited nuclear microsatellites explained the historical limits of invasions, suggesting that dispersing male bats spread VBRV between genetically isolated female populations. Host nuclear DNA further indicated unanticipated gene flow through the Andes mountains connecting the VBRV-free Pacific coast to the VBRV-endemic Amazon rainforest. By combining Bayesian phylogeography with landscape resistance models, we projected invasion routes through northern Peru that were validated by real-time livestock rabies mortality data. The first outbreaks of VBRV on the Pacific coast of South America could occur by June 2020, which would have serious implications for agriculture, wildlife conservation, and human health. Our results show that combining host and pathogen genetic data can identify sex biases in pathogen spatial spread, which may be a widespread but underappreciated phenomenon, and demonstrate that genetic forecasting can aid preparedness for impending viral invasions.
- MeSH
- Bayesova věta MeSH
- biologická evoluce * MeSH
- Chiroptera virologie MeSH
- genom virový MeSH
- interakce hostitele a patogenu * MeSH
- mikrosatelitní repetice genetika MeSH
- rabies epidemiologie MeSH
- roční období MeSH
- typy dědičnosti genetika MeSH
- virus rabies genetika MeSH
- zeměpis MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Geografické názvy
- Peru epidemiologie MeSH
Grampozitívne baktérie Enterococcus faecalis a E. faecium sú komensálne organizmy, ktoré sa pod vplyvom selekčného tlaku menia na pôvodcov infekčných ochorení. Z dôvodu prirodzenej rezistencie a efektívnych mechanizmov prenosu genetického materiálu je terapia enterokokových ochorení náročná. V antiinfekčnej terapii majú významné postavenie aminoglykozidy. Baktericídny účinok, vhodné farmakokinetické vlastnosti a synergické pôsobenie s beta-laktámami a glykopeptidmi podporujú ich používanie v terapeutickej praxi. K hlavným mechanizmom rezistencie voči aminoglykozidom patrí enzymatická inaktivácia antibiotika aminoglykozid=modifikujúcimi enzýmami (AGMEs), ktoré sa líšia schopnosťou inaktivovať rozdielne spektrum aminoglykozidov. K patogenite enterokokov prispievajú nemalou mierou aj faktory virulencie, ktorých participácia v patogenéze infekčných ochorení je zatiaľ nedostatočne objasnená. Vlastnosti enterokokov ako produkcia beta-hemolyzínu (Hly), želatinázy (Gel), agregačnej substancie (AS) a syntéza enterokokového povrchového proteínu (Esp) patria medzi najčastejšie študované potenciálne faktory virulencie.
Enterococcus faecalis and E. faecium are grampositive commensal bacteria that may become pathogenic under the selection pressure. In view of natural resistance and effective mechanisms of genetic transfer, the treatment of enterococcal diseases is rather complicated. Aminoglycosides are clinically relevant antimicrobials that are frequently prescribed in practice since having good pharmacokinetics and showing synergism with beta-lactam and glycopeptides. One of the major mechanisms involved in aminoglycoside resistance is inactivation of the antibiotic agent by aminoglycoside-modifying enzymes (AGMEs) differing in the capacity for inactivation of specific types of aminoglycosides. The factors of virulence are also involved in enterococcal pathogenicity but their role in the pathogenesis of infectious diseases remains unclear. Production of betahemolysin (Hly), gelatinase (Gel), and aggregation substance (AS), and synthesis of enterococcal surface protein (Esp) are among the most frequently studied potential virulence factors.
The oomycete Aphanomyces astaci causes mass mortalities of European crayfish. Different species of North American crayfish, original hosts of this parasite, seem to carry different strains of A. astaci. So far, four distinct genotype groups have been recognised using Random Amplification of Polymorphic DNA (RAPD-PCR). We succeeded in isolating A. astaci from the spiny-cheek crayfish Orconectes limosus, a widespread invader in Europe, and confirmed that this species carries a novel A. astaci genotype. Improving knowledge on the diversity of this parasite may facilitate identification of genotypes in mass mortalities of European crayfish, thus tracing the sources of infection.
- MeSH
- Aphanomyces klasifikace genetika patogenita MeSH
- DNA fungální analýza MeSH
- druhová specificita MeSH
- fylogeneze MeSH
- genetická variace MeSH
- genotyp MeSH
- infekce veterinární MeSH
- interakce hostitele a patogenu MeSH
- severní raci mikrobiologie fyziologie MeSH
- technika náhodné amplifikace polymorfní DNA MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Bakteriální zoonózy představují i v současnosti závažný medicínský problém. K méně častým, ale závažným zoonózám patří maltská horečka způsobená bakterií Brucella melitensis. Předkládaná kazuistika popisuje případ relapsu importované maltské horečky u mladého muže. Diagnóza byla vedle čtyř sérologických testů verifikována přímým průkazem původce v hemokultuře. Izolát Brucella melitensis byl identifikován metodou polymerázové řetězové reakce a metodou hmotností spektrometrie MALDI-TOF.
Bacterial zoonoses still represent a serious medical problem. One of the less frequent but severe zoonoses is brucellosis caused by the bacterium Brucella melitensis. The presented case report describes relapsing imported brucellosis in a young male. In addition to four serological tests, the diagnosis was confirmed by direct detection of the pathogen in blood culture. The isolate of Brucella melitensis was identified using the MALDI-TOF BioTyper method and subsequently also by PCR.
- Klíčová slova
- MALDI-TOF, alimentární infekce, zoonóza,
- MeSH
- Brucella melitensis izolace a purifikace MeSH
- brucelóza diagnóza mikrobiologie MeSH
- cestování MeSH
- lidé MeSH
- mladý dospělý MeSH
- Check Tag
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
