Microorganisms are not commonly found in the planktonic state but predominantly form dual- and multispecies biofilms in almost all natural environments. Bacteria in multispecies biofilms cooperate, compete or have neutral interactions according to the involved species. Here, the development of mono- and dual-species biofilms formed by Staphylococcus aureus and other foodborne pathogens such as Salmonella enterica subsp. enterica serovar Enteritidis, potentially pathogenic Raoultella planticola and non-pathogenic Escherichia coli over the course of 24, 48 and 72 h was studied. Biofilm formation was evaluated by the crystal violet assay (CV), enumeration of colony-forming units (CFU cm-2) and visualization using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). In general, Gram-negative bacterial species and S. aureus interacted in a competitive manner. The tested Gram-negative bacteria grew better in mixed dual-species biofilms than in their mono-species biofilms as determined using the CV assay, CFU ml-2enumeration, and CLSM and SEM visualization. In contrast, the growth of S. aureus biofilms was reduced when cultured in dual-species biofilms. CLSM images revealed grape-like clusters of S. aureus and monolayers of Gram-negative bacteria in both mono- and dual-species biofilms. S. aureus clusters in dual-species biofilms were significantly smaller than clusters in S. aureus mono-species biofilms.
- MeSH
- barvení a značení MeSH
- biofilmy růst a vývoj MeSH
- Enterobacteriaceae růst a vývoj fyziologie MeSH
- genciánová violeť analýza MeSH
- konfokální mikroskopie MeSH
- mikrobiální interakce * MeSH
- mikroskopie elektronová rastrovací MeSH
- počet mikrobiálních kolonií MeSH
- Staphylococcus aureus růst a vývoj fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
The genus Raoultella belongs to the family of Enterobacteriaceae. Raoultella spp. are Gram-negative, aerobic, non-motile rods. This genus can be distinguished from the genus Klebsiella, in that genus use histamine as the only source of carbon in the medium. Also, Raoultella grow at 4 °C and do not produce gas from lactose at 44.5 °C. Raoultella sp. is known to inhabit natural environments (water, soil, plants). The reservoir of Raoultella is the gastrointestinal tract and upper respiratory tract. Raoultella spp. are opportunistic bacteria, which usually cause infections of the biliary tract, pneumonia and bacteraemia in oncologic and with lower immunity patients. Raoultella planticola and Raoultella ornithinolytica are the most frequently encountered human pathogens among the genus Raoultella. In this review, the current knowledge on Raoultella infections is summarized.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální léková rezistence MeSH
- bakteriální pneumonie epidemiologie mikrobiologie patologie MeSH
- bakteriemie epidemiologie mikrobiologie patologie MeSH
- bakteriologické techniky MeSH
- cholecystitida epidemiologie mikrobiologie patologie MeSH
- Enterobacteriaceae účinky léků izolace a purifikace fyziologie MeSH
- enterobakteriální infekce epidemiologie mikrobiologie patologie MeSH
- lidé MeSH
- oportunní infekce epidemiologie mikrobiologie patologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Eukaryotes commonly host communities of heritable symbiotic bacteria, many of which are not essential for their hosts' survival and reproduction. There is laboratory evidence that these facultative symbionts can provide useful adaptations, such as increased resistance to natural enemies. However, we do not know how symbionts affect host fitness when the latter are subject to attack by a natural suite of parasites and pathogens. Here, we test whether two protective symbionts, Regiella insecticola and Hamiltonella defensa, increase the fitness of their host, the pea aphid (Acyrthosiphon pisum), under natural conditions. We placed experimental populations of two pea aphid lines, each with and without symbionts, in five wet meadow sites to expose them to a natural assembly of enemy species. The aphids were then retrieved and mortality from parasitoids, fungal pathogens and other causes assessed. We found that both Regiella and Hamiltonella reduce the proportion of aphids killed by the specific natural enemies against which they have been shown to protect in laboratory and cage experiments. However, this advantage was nullified (Hamiltonella) or reversed (Regiella) by an increase in mortality from other natural enemies and by the cost of carrying the symbiont. Symbionts therefore affect community structure by altering the relative success of different natural enemies. Our results show that protective symbionts are not necessarily advantageous to their hosts, and may even behave more like parasites than mutualists. Nevertheless, bacterial symbionts may play an important role in determining food web structure and dynamics.
- MeSH
- Enterobacteriaceae fyziologie MeSH
- genetická zdatnost MeSH
- houby fyziologie MeSH
- interakce hostitele a parazita MeSH
- interakce hostitele a patogenu * MeSH
- mšice genetika mikrobiologie parazitologie fyziologie MeSH
- sršňovití fyziologie MeSH
- symbióza * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Symbiosis between insects and bacteria result in a variety of arrangements, genomic modifications, and metabolic interconnections. Here, we present genomic, phylogenetic, and morphological characteristics of a symbiotic system associated with Melophagus ovinus, a member of the blood-feeding family Hippoboscidae. The system comprises four unrelated bacteria representing different stages in symbiosis evolution, from typical obligate mutualists inhabiting bacteriomes to freely associated commensals and parasites. Interestingly, the whole system provides a remarkable analogy to the association between Glossina and its symbiotic bacteria. In both, the symbiotic systems are composed of an obligate symbiont and two facultative intracellular associates, Sodalis and Wolbachia. In addition, extracellular Bartonella resides in the gut of Melophagus. However, the phylogenetic origins of the two obligate mutualist symbionts differ. In Glossina, the mutualistic Wigglesworthia appears to be a relatively isolated symbiotic lineage, whereas in Melophagus, the obligate symbiont originated within the widely distributed Arsenophonus cluster. Although phylogenetically distant, the two obligate symbionts display several remarkably similar traits (e.g., transmission via the host's "milk glands" or similar pattern of genome reduction). To obtain better insight into the biology and possible role of the M. ovinus obligate symbiont, "Candidatus Arsenophonus melophagi," we performed several comparisons of its gene content based on assignments of the Cluster of Orthologous Genes (COG). Using this criterion, we show that within a set of 44 primary and secondary symbionts, "Ca. Arsenophonus melophagi" is most similar to Wigglesworthia. On the other hand, these two bacteria also display interesting differences, such as absence of flagellar genes in Arsenophonus and their presence in Wigglesworthia. This finding implies that a flagellum is not essential for bacterial transmission via milk glands.
- MeSH
- DNA bakterií chemie genetika MeSH
- Enterobacteriaceae klasifikace genetika izolace a purifikace fyziologie MeSH
- fylogeneze MeSH
- genom bakteriální MeSH
- mikroskopie MeSH
- molekulární sekvence - údaje MeSH
- moucha tse-tse mikrobiologie fyziologie MeSH
- Phthiraptera mikrobiologie fyziologie MeSH
- sekvenční analýza DNA MeSH
- sekvenční homologie MeSH
- shluková analýza MeSH
- symbióza * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Raoultella spp. representatives are Gram-negative capsulated, nonmotile rods. These bacteria are found in the natural environment: plants, water, soil and insects. R. ornithinolytica is one of the three species of Raoultella. R. ornithinolytica is the only species within the genus which has the ability to produce ornithine decarboxylase. Human infections related to R. ornithinolytica are exceedingly rare. The present case report describes catheter-related blood stream infection caused by R. ornithinolytica and successfully treated with antibiotic therapy.
- MeSH
- antibakteriální látky aplikace a dávkování MeSH
- bakteriemie farmakoterapie mikrobiologie MeSH
- dítě MeSH
- Enterobacteriaceae genetika izolace a purifikace fyziologie MeSH
- enterobakteriální infekce farmakoterapie mikrobiologie MeSH
- katétrové infekce farmakoterapie mikrobiologie MeSH
- lidé MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH
- práce podpořená grantem MeSH
Bacteria of the genus Sodalis live in symbiosis with various groups of insects. The best known member of this group, a secondary symbiont of tsetse flies Sodalis glossinidius, has become one of the most important models in investigating establishment and evolution of insect-bacteria symbiosis. It represents a bacterium in the early/intermediate state of the transition towards symbiosis, which allows for exploring such interesting topics as: usage of secretory systems for entering the host cell, tempo of the genome modification, and metabolic interaction with a coexisting primary symbiont. In this study, we describe a new Sodalis species which could provide a useful comparative model to the tsetse symbiont. It lives in association with Melophagus ovinus, an insect related to tsetse flies, and resembles S. glossinidius in several important traits. Similar to S. glossinidius, it cohabits the host with another symbiotic bacterium, the bacteriome-harbored primary symbiont of the genus Arsenophonus. As a typical secondary symbiont, Candidatus Sodalis melophagi infects various host tissues, including bacteriome. We provide basic morphological and molecular characteristics of the symbiont and show that these traits also correspond to the early/intermediate state of the evolution towards symbiosis. Particularly, we demonstrate the ability of the bacterium to live in insect cell culture as well as in cell-free medium. We also provide basic characteristics of type three secretion system and using three reference sequences (16 S rDNA, groEL and spaPQR region) we show that the bacterium branched within the genus Sodalis, but originated independently of the two previously described symbionts of hippoboscoids. We propose the name Candidatus Sodalis melophagi for this new bacterium.
- MeSH
- DNA bakterií genetika MeSH
- Enterobacteriaceae genetika metabolismus fyziologie MeSH
- fylogeneze * MeSH
- molekulární evoluce MeSH
- moucha tse-tse mikrobiologie MeSH
- ribozomální DNA genetika MeSH
- sekvenční analýza DNA MeSH
- symbióza * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: The bacterial family Enterobacteriaceae gave rise to a variety of symbiotic forms, from the loosely associated commensals, often designated as secondary (S) symbionts, to obligate mutualists, called primary (P) symbionts. Determination of the evolutionary processes behind this phenomenon has long been hampered by the unreliability of phylogenetic reconstructions within this group of bacteria. The main reasons have been the absence of sufficient data, the highly derived nature of the symbiont genomes and lack of appropriate phylogenetic methods. Due to the extremely aberrant nature of their DNA, the symbiotic lineages within Enterobacteriaceae form long branches and tend to cluster as a monophyletic group. This state of phylogenetic uncertainty is now improving with an increasing number of complete bacterial genomes and development of new methods. In this study, we address the monophyly versus polyphyly of enterobacterial symbionts by exploring a multigene matrix within a complex phylogenetic framework. RESULTS: We assembled the richest taxon sampling of Enterobacteriaceae to date (50 taxa, 69 orthologous genes with no missing data) and analyzed both nucleic and amino acid data sets using several probabilistic methods. We particularly focused on the long-branch attraction-reducing methods, such as a nucleotide and amino acid data recoding and exclusion (including our new approach and slow-fast analysis), taxa exclusion and usage of complex evolutionary models, such as nonhomogeneous model and models accounting for site-specific features of protein evolution (CAT and CAT+GTR). Our data strongly suggest independent origins of four symbiotic clusters; the first is formed by Hamiltonella and Regiella (S-symbionts) placed as a sister clade to Yersinia, the second comprises Arsenophonus and Riesia (S- and P-symbionts) as a sister clade to Proteus, the third Sodalis, Baumannia, Blochmannia and Wigglesworthia (S- and P-symbionts) as a sister or paraphyletic clade to the Pectobacterium and Dickeya clade and, finally, Buchnera species and Ishikawaella (P-symbionts) clustering with the Erwinia and Pantoea clade. CONCLUSIONS: The results of this study confirm the efficiency of several artifact-reducing methods and strongly point towards the polyphyly of P-symbionts within Enterobacteriaceae. Interestingly, the model species of symbiotic bacteria research, Buchnera and Wigglesworthia, originated from closely related, but different, ancestors. The possible origins of intracellular symbiotic bacteria from gut-associated or pathogenic bacteria are suggested, as well as the role of facultative secondary symbionts as a source of bacteria that can gradually become obligate maternally transferred symbionts.
- MeSH
- Bayesova věta MeSH
- Buchnera genetika fyziologie MeSH
- DNA bakterií genetika MeSH
- Enterobacteriaceae genetika fyziologie MeSH
- fylogeneze MeSH
- genom bakteriální MeSH
- molekulární evoluce MeSH
- symbióza MeSH
- Wigglesworthia genetika fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Vývoj imunitního slizničního systému je výsledkem interakce s vnějším prostředím. Kojení pozitivně ovlivňuje kolonizaci GIT. Prebiotika ovlivňují pozitivně mikroflóru střevního ústrojí a mohou ovlivnit i abnormální imunologickou reaktivitu u dětí.
The development of mucosal immune system of digestive tract is by determined enviroment influences. The colonisation of digestive tract is positively regulated by breast feeding. The gut microflora is positively modulated by prebiotics. It is possible to influence the development of immunopathological reactivity in children.
- Klíčová slova
- Nutrilon HA 3,
- MeSH
- dítě MeSH
- Enterobacteriaceae fyziologie imunologie MeSH
- kojenec MeSH
- kojení MeSH
- lidé MeSH
- mateřské mléko imunologie MeSH
- náhražky mateřského mléka metabolismus MeSH
- oligosacharidy farmakologie terapeutické užití MeSH
- probiotika farmakologie terapeutické užití MeSH
- sliznice fyziologie imunologie MeSH
- Check Tag
- dítě MeSH
- kojenec MeSH
- lidé MeSH
- Publikační typ
- přehledy MeSH
V posledních desetiletích je pozorován značný nárůst alergických onemocnění u dětí. K tomuto nárůstu dochází především v ekonomicky rozvinutých zemích. Zvýšení je pozorováno ve všech skupinách alergických onemocnění. Především jde o atopický ekzém a alergickou rýmu. Nejdramatičtější je vzestup potravinové alergie a anafylaxe. Alergická onemocnění u postižených jedinců často přetrvávají do dospělého věku. Výzkumu těchto onemocnění je věnována velká pozornost. I přes to, že v posledních letech byly ve výzkumu učiněny značné pokroky, nebyly nalezeny jasné důvody, které vedou k tak dramatickému nárůstu incidence alergických onemocnění. Předpokládá se, že jde o řadu genetických vlivů a že se uplatňuje i mnoho faktorů zevního prostředí. Epidemiologické studie ukazují, že pro rozvoj onemocnění je kritickým obdobím časný kojenecký věk. Nyní je věnována pozornost vývoji strategií primární prevence.
- MeSH
- alergie prevence a kontrola MeSH
- atopická dermatitida prevence a kontrola MeSH
- Enterobacteriaceae fyziologie metabolismus MeSH
- fyziologie výživy dětí fyziologie MeSH
- fyziologie výživy kojenců fyziologie MeSH
- kojenec MeSH
- lidé MeSH
- primární prevence metody MeSH
- probiotika terapeutické užití MeSH
- rizikové faktory MeSH
- Check Tag
- kojenec MeSH
- lidé MeSH
Kontakt organismu s obrovským kvantem infekčních i neinfekčních podnětů z vnějšího prostředí se odehrává na epitelových površích sliznic a kůže. Imunitní systém sliznic zabraňuje pronikání infekčních a imunogenních složek ze sliznic do cirkulace (bariérová funkce), zajišťuje obranu proti patogenním mikrorganismům (antiinfekční úloha), zároveň však zajišťuje i nereaktivnost imunitního systému vůči neškodným složkám potravy a mikroflóry přítomným na sliznicích („orální nebo slizniční“ tolerance).
