Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| vaccination with an attenuated strain of francisella novicida prevents t-cell depletion and protects mice infected with the wild-type strain from severe sepsis. | francisella tularensis is the causative agent of zoonotic tularemia, a severe pneumonia in humans, and francisella novicida causes a similarly severe tularemia in mice upon inhalation. the correlates of protective immunity, as well as the virulence mechanisms of this deadly pathogen, are not well understood. in the present study, we compared the host immune responses of lethally infected and vaccinated mice to highlight the host determinants of protection from this disease. intranasal infection ... | 2009 | 19635830 |
| evidence for the presence of francisella and spotted fever group rickettsia dna in the tick amblyomma fimbriatum (acari: ixodidae), northern territory, australia. | ticks (n = 252) were collected from five wild-caught reptile species during routine trapping in the djukbinj national park and fogg dam reserve, northern territory, australia. pooling of ticks (one to four ticks per pool), according to sex or host animal, resulted in 187 samples used for screening for the presence of rickettsia species via molecular methods. rickettsia dna was detected via the amplification of the glta, ompa, and ompb genes in 57 (34%) of the 187 tick samples, all of which conta ... | 2009 | 19645299 |
| vaccination with a defined francisella tularensis subsp. novicida pathogenicity island mutant (deltaiglb) induces protective immunity against homotypic and heterotypic challenge. | francisella tularensis, an intracellular gram-negative bacterium, is the causative agent of tularemia and a potential bioweapon. currently, there is no licensed vaccine against this organism. we have characterized the efficacy of a defined f. tularensis subsp. novicida mutant (deltaiglb) as a live attenuated vaccine against pneumonic tularemia. replication of the iglb mutant (kkf235) in murine macrophages was significantly lower than the wild type novicida strain u112, and exhibited an ld(50) gr ... | 2009 | 19651173 |
| the 58-kilodalton major virulence factor of francisella tularensis is required for efficient utilization of iron. | we investigated the role of the 58-kda ftt0918 protein in the iron metabolism of francisella tularensis. the phenotypes of schu s4, a prototypic strain of f. tularensis subsp. tularensis, and the delta ftt0918 and delta fsla isogenic mutants were analyzed. the gene product missing in the delta fsla mutant is responsible for synthesis of a siderophore. when grown in broth with various iron concentrations, the two deletion mutants generally reached lower maximal densities than schu s4. the delta f ... | 2009 | 19651867 |
| loops and networks in control of francisella tularensis virulence. | francisella tularensis is a highly infectious, gram-negative bacterium responsible for the disease tularemia in a broad variety of animals, including humans. f. tularensis intracellular multiplication occurs mainly in macrophages. however, f. tularensis is able to infect many other cell types, including other phagocytic (dendritic cells, polymorphonuclear leukocytes) and nonphagocytic (alveolar epithelial cells, hepatocytes, endothelial cells and fibroblasts) cells. the ability of professional p ... | 2009 | 19659427 |
| the role of birds in dissemination of francisella tularensis: first direct molecular evidence for bird-to-human transmission. | during a recent large tularemia outbreak in bulgaria we found several cases that were remote from the main focus. one case had an unusual mode of transmission. a hunter acquired tularemia through a nail scratch from a buzzard (buteo buteo) and consequently developed a typical ulceroglandular form of the disease. the diagnosis was confirmed by serological methods and successful cultivation. comparative strain typing was performed by high-resolution multi-locus variable-number tandem repeat analys ... | 2010 | 19664305 |
| diversity of francisella species in environmental samples from martha's vineyard, massachusetts. | we determined whether francisella spp. are present in water, sediment, and soil from an active tularemia natural focus on martha's vineyard, massachusetts, during a multiyear outbreak of pneumonic tularemia. environmental samples were tested by polymerase chain reaction (pcr) targeting francisella species 16s rrna gene and succinate dehydrogenase a (sdha) sequences; evidence of the agent of tularemia was sought by amplification of francisella tularensis-specific sequences for the insertion eleme ... | 2010 | 19669828 |
| identification of francisella tularensis live vaccine strain cuzn superoxide dismutase as critical for resistance to extracellularly generated reactive oxygen species. | francisella tularensis is an intracellular pathogen whose survival is in part dependent on its ability to resist the microbicidal activity of host-generated reactive oxygen species (ros) and reactive nitrogen species (rns). in numerous bacterial pathogens, cuzn-containing superoxide dismutases (sodc) are important virulence factors, localizing to the periplasm to offer protection from host-derived superoxide radicals (o(2)(-)). in the present study, mutants of f. tularensis live vaccine strain ( ... | 2009 | 19684141 |
| real-time pcr strategy and detection of bacterial agents of lymphadenitis. | the aim of this study was to compare 16 s rrna gene amplification and sequencing with a systematic real-time pcr assay screening strategy that includes all common known pathogens recovered from lymph node biopsy specimens. lymph node biopsy samples sent to our laboratory from january 2007 to december 2008 were tested in the study. lymph nodes were screened for the presence of any bacteria by pcr amplification and sequencing targeting the 16 s rrna gene and also by a specific real-time pcr strate ... | 2009 | 19685089 |
| [tularemia]. | tularemia is a zoonotic disease caused by francisella tularensis. the etiological agent is transmitted to man by direct contact with infected animals, air, water or contaminated food, or through hematophagous vectors. in portugal, in 1998, after an outbreak in spain, the direcção geral de saúde issued a warning, alerting the clinicians to the possibility of the disease spreading throughout the national territory. in this work, an epidemiological review of tularemia is made in order to contribute ... | 2009 | 19686629 |
| francisella tularensis induces ubiquitin-dependent major histocompatibility complex class ii degradation in activated macrophages. | the intracellular bacterium francisella tularensis survives and replicates within macrophages, ultimately killing the host cell. resolution of infection requires the development of adaptive immunity through presentation of f. tularensis antigens to cd4+ and cd8+ t cells. we have previously established that f. tularensis induces macrophage prostaglandin e2 (pge2) production, leading to skewed t-cell responses. pge2 can also downregulate macrophage major histocompatibility complex (mhc) class ii e ... | 2009 | 19703975 |
| francisella tularensis induces extensive caspase-3 activation and apoptotic cell death in the tissues of infected mice. | although francisella tularensis subsp. tularensis is known to cause extensive tissue necrosis, the pathogenesis of tissue injury has not been elucidated. to characterize cell death in tularemia, c57bl/6 mice were challenged by the intranasal route with type a f. tularensis, and the pathological changes in infected tissues were characterized over the next 4 days. at 3 days postinfection, well-organized inflammatory infiltrates developed in the spleen and liver following the spread of infection fr ... | 2009 | 19703976 |
| cgug: in silico proteome and genome parsing tool for the determination of "core" and unique genes in the analysis of genomes up to ca. 1.9 mb. | viruses and small-genome bacteria (~2 megabases and smaller) comprise a considerable population in the biosphere and are of interest to many researchers. these genomes are now sequenced at an unprecedented rate and require complementary computational tools to analyze. "coregenesuniquegenes" (cgug) is an in silico genome data mining tool that determines a "core" set of genes from two to five organisms with genomes in this size range. core and unique genes may reflect similar niches and needs, and ... | 2009 | 19706165 |
| a possible novel francisella genomic species isolated from blood and urine of a patient with severe illness. | two identical isolates were recovered in pure culture from the blood and urine of a patient suffering from severe septicaemia associated with obstructive pyelonephritis secondary to lithotripsy. preliminary phenotypic and genotypic characterizations based on serological, biochemical and sequence analyses following pcr amplification of selected gene regions indicate that this organism represents a potential new francisella genomic species. | 2010 | 19709068 |
| [prevalence of epidemic outbreak of tularemia in the hospital universitario río hortega (spain) in the year 2007]. | this present research study presents the analytic results of an outbreak of tularemia (francisella tularensis) that occurred in the northwest areas of castilla y león in northern spain in late june 2007. | 2009 | 19709538 |
| [tularemia as a pediatric problem]. | the diagnosis of tularemia is based on the clinical picture, and epidemics are brief and local. in children, recognition of tularaemia may be challenging, as an inflamed mosquito bite mark may be covered under the hair, and lymph node enlargement is associated with other febrile diseases as well. half of the children have vesicopapular skin changes. fluoroqinolones and aminoglycosides area effective against francisella tularensis in vitro, and the efficacy of treatment seems to be the better the ... | 2009 | 19711573 |
| tularemia. | tularemia is a potentially fatal multi-systemic disease of humans and other animals caused by the bacterial pathogen francisella tularensis. the disease can be transmitted by ticks, biting flies, water exposure, food, and aerosols and occurs around the northern hemisphere including north america, europe, and asia. there are several defined species and subspecies, including f. tularensis subsp. tularensis (jellison type a) which is pathogenic for rabbits and occurs in north america, f. tularensis ... | 2010 | 19713053 |
| editorial: proinflammatory cytokines in pneumonic tularemia: too much too late? | 2009 | 19720615 | |
| substituted diphenyl ethers as a broad-spectrum platform for the development of chemotherapeutics for the treatment of tularaemia. | the national institute of allergy and infectious disease classifies francisella tularensis as a category a priority pathogen. despite the availability of drugs for treating tularaemia, the mortality in naturally acquired cases can still approach 30%. in addition, the usefulness of existing drugs for treatment in response to exposure or for prophylaxis is limited because of toxicity and delivery concerns. the aim of this study was to assess the efficacy of the lead alkyl-substituted diphenyl ethe ... | 2009 | 19734171 |
| innate immune response during yersinia infection: critical modulation of cell death mechanisms through phagocyte activation. | yersinia pestis, the etiological agent of plague, is one of the most deadly pathogens on our planet. this organism shares important attributes with its ancestral progenitor, yersinia pseudotuberculosis, including a 70-kb virulence plasmid, lymphotropism during growth in the mammalian host, and killing of host macrophages. infections with both organisms are biphasic, where bacterial replication occurs initially with little inflammation, followed by phagocyte influx, inflammatory cytokine producti ... | 2009 | 19734471 |
| global transcriptional response to spermine, a component of the intramacrophage environment, reveals regulation of francisella gene expression through insertion sequence elements. | tularemia is caused by the category a biodefense agent francisella tularensis. this bacterium is associated with diverse environments and a plethora of arthropod and mammalian hosts. how f. tularensis adapts to these different conditions, particularly the eukaryotic intracellular environment in which it replicates, is poorly understood. here, we demonstrate that the polyamines spermine and spermidine are environmental signals that alter bacterial stimulation of host cells. genomewide analysis sh ... | 2009 | 19749055 |
| a novel role for plasmin-mediated degradation of opsonizing antibody in the evasion of host immunity by virulent, but not attenuated, francisella tularensis. | opsonization by abs represents a critical component of the host immune response against many pathogens. the mechanisms by which virulent microbes evade this protective response are not completely understood. in disease mediated by francisella tularensis, ab can effectively protect against infections with attenuated strains, for example, lvs, but not virulent strains such as schus4. thus, it is likely that schus4 has mechanisms, which are not present in lvs, that allow evasion of opsonization by ... | 2009 | 19752236 |
| complete genome sequence of francisella tularensis subspecies holarctica ftnf002-00. | francisella tularensis subspecies holarctica ftnf002-00 strain was originally obtained from the first known clinical case of bacteremic f. tularensis pneumonia in southern europe isolated from an immunocompetent individual. the ftnf002-00 complete genome contains the rd(23) deletion and represents a type strain for a clonal population from the first epidemic tularemia outbreak in spain between 1997-1998. here, we present the complete sequence analysis of the ftnf002-00 genome. the complete genom ... | 2009 | 19756146 |
| differentiation of gram-negative bacterial aerosol exposure using detected markers in bronchial-alveolar lavage fluid. | the identification of biosignatures of aerosol exposure to pathogens has the potential to provide useful diagnostic information. in particular, markers of exposure to different types of respiratory pathogens may yield diverse sets of markers that can be used to differentiate exposure. we examine a mouse model of aerosol exposure to known gram negative bacterial pathogens, francisella tularensis novicida and pseudomonas aeruginosa. mice were subjected to either a pathogen or control exposure and ... | 2009 | 19756149 |
| rela regulates virulence and intracellular survival of francisella novicida. | analysis of the genome of francisella tularensis has revealed few regulatory systems, and how the organism adapts to conditions in different niches is poorly understood. the stringent response is a global stress response mediated by (p)ppgpp. the enzyme rela has been shown to be involved in generation of this signal molecule in a range of bacterial species. we investigated the effect of inactivation of the rela gene in francisella by generating a mutant in francisella novicida. under amino acid ... | 2009 | 19762448 |
| francisella novicida forms in vitro biofilms mediated by an orphan response regulator. | francisella tularensis is associated with water and waterways and infects many species of animals, insects, and protists. the mechanism francisella utilizes to persist in the environment and in tick vectors is currently unknown. we have demonstrated for the first time that francisella novicida, a model organism of f. tularensis, forms a biofilm in vitro. selected f. novicida transposon mutants were tested for their ability to form biofilm compared to the wildtype f. novicida strain. mutation of ... | 2010 | 19763680 |
| survival of secondary lethal systemic francisella lvs challenge depends largely on interferon gamma. | although survival of primary infection with the live vaccine strain (lvs) of francisella tularensis depends on interferon gamma (ifn-gamma), the relative importance of ifn-gamma to secondary protective immunity in vivo has not been clearly established. here we examine the role of ifn-gamma in t cell priming and expression of vaccine-induced protection against lethal intraperitoneal challenge of mice. large amounts of ifn-gamma were detected between days 3 and 7 in the sera of lvs-immunized mice, ... | 2010 | 19781659 |
| francisella asiatica sp. nov. isolated from farmed tilapia (oreochromis sp.) and elevation of francisella philomiragia subsp. noatunensis to species rank as francisella noatunensis comb. nov., sp. nov. | bacterial isolates from diseased farmed tilapia (oreochromis sp.) from costa rica (pq 1104), atlantic salmon (salmo salar) from chile (pq 1106) and three-line grunt (parapristipoma trilineatum) from japan (ehime-1) were characterized by phenotypic and molecular taxonomic methods. these isolates were gram-negative, oxidase negative, non-motile, strictly aerobic cocco-bacilli, produced h2s from cysteine supplemented media, which is phenotypically consistent with the genus francisella. comparison o ... | 2009 | 19783606 |
| description of francisella hispaniensis sp. nov., isolated from human blood, reclassification of francisella novicida (larson et al. 1955) olsufiev et al. 1959 as francisella tularensis subsp. novicida comb. nov. and emended description of the genus francisella. | strain fhsp1t, isolated from human blood in spain in 2003, was studied for its taxonomic allocation. by 16s rrna and reca gene sequencing, the strain was shown to belong to the genus francisella. in the 16s rrna gene sequence, francisella sp. fhsp1t shared similarity of more than 99% with strains of francisella tularensis subspecies and francisella novicida u112t, 98% with francisella piscicida gm2212t and 98.4% with francisella philomiragia atcc 25015t. in the reca gene sequence, francisella sp ... | 2010 | 19783615 |
| francisella tularensis novicida proteomic and transcriptomic data integration and annotation based on semantic web technologies. | this paper summarises the lessons and experiences gained from a case study of the application of semantic web technologies to the integration of data from the bacterial species francisella tularensis novicida (fn). fn data sources are disparate and heterogeneous, as multiple laboratories across the world, using multiple technologies, perform experiments to understand the mechanism of virulence. it is hard to integrate these data sources in a flexible manner that allows new experimental data to b ... | 2009 | 19796400 |
| proteome analysis of an attenuated francisella tularensis dsba mutant: identification of potential dsba substrate proteins. | francisella tularensis (f. tularensis) is highly infectious for humans via aerosol route and untreated infections with the highly virulent subsp. tularensis can be fatal. our knowledge regarding key virulence determinants has increased recently but is still somewhat limited. surface proteins are potential virulence factors and therapeutic targets, and in this study, we decided to target three genes encoding putative membrane lipoproteins in f. tularensis lvs. one of the genes encoded a protein w ... | 2009 | 19799467 |
| generation of heterogeneous memory t cells by live attenuated tularemia vaccine in humans. | there is very limited evidence concerning the phenotype, function, and homing characteristics of memory t (t(m)) cells elicited by vaccination against intracellular bacteria in humans. here we studied t(m) subsets elicited by exposure to francisella tularensis in humans as a model of immunity to intracellular bacteria. to this end, t(m) cells were evaluated in two groups: (1) subjects immunized with live attenuated tularemia vaccine by skin scarification and (2) tularemia naturally infected subj ... | 2009 | 19799845 |
| [severe tularaemia mimicking glandular tuberculosis during adalimumab therapy]. | tularaemia is an anthropozoonosis, transmitted by small mammals (hares) and arthropods (ticks, horseflies). the causative agent is francisella tularensis, a facultatively intracellular gram-negative bacillus. we report a case of tularaemia in its ulceroglandular form occurring during methotrexate and adalimumab treatment (humira) for rheumatoid arthritis. | 2009 | 19801257 |
| programmed cell death and the pathogenesis of tissue injury induced by type a francisella tularensis. | francisella tularensis is a highly virulent bacterial species that causes various forms of tularemia in humans. the urgency in understanding the pathogenesis of these diseases has stimulated unprecedented interest in this bacterial species over the past few years. recent findings underscore a number of important distinctions between the francisella ssp. and emphasize the importance of using type a f. tularensis strains when characterizing pathophysiological responses that are relevant to the let ... | 2009 | 19811540 |
| whole genome single nucleotide polymorphism based phylogeny of francisella tularensis and its application to the development of a strain typing assay. | a low genetic diversity in francisella tularensis has been documented. current dna based genotyping methods for typing f. tularensis offer a limited and varying degree of subspecies, clade and strain level discrimination power. whole genome sequencing is the most accurate and reliable method to identify, type and determine phylogenetic relationships among strains of a species. however, lower cost typing schemes are necessary in order to enable typing of hundreds or even thousands of isolates. | 2009 | 19811647 |
| [a patient with a fever and an eschar caused by tularemia]. | a 38-year-old man presented at the first-aid department complaining of fever, general malaise and a painful left groin. the complaints had started shortly after an active holiday in finland. physical examination showed enlarged left sided inguinal lymph nodes and a marked eschar on the left lower leg. in terms of differential diagnosis a rickettsia or a tularemia infection were considered. the pathogen for tularemia, francisella tularensis subspecies holarctica, was isolated in wound discharge f ... | 2009 | 19818182 |
| francisella tularensis type a strains cause the rapid encystment of acanthamoeba castellanii and survive in amoebal cysts for three weeks postinfection. | francisella tularensis, the causative agent of the zoonotic disease tularemia, has recently gained increased attention due to the emergence of tularemia in geographical areas where the disease has been previously unknown and to the organism's potential as a bioterrorism agent. although f. tularensis has an extremely broad host range, the bacterial reservoir in nature has not been conclusively identified. in this study, the ability of virulent f. tularensis strains to survive and replicate in the ... | 2009 | 19820161 |
| humans and evolutionary and ecological forces shaped the phylogeography of recently emerged diseases. | the development of human civilizations and global commerce has led to the emergence and worldwide circulation of many infectious diseases. anthrax, plague and tularaemia are three zoonotic diseases that have been intensely studied through genome characterization of the causative species and phylogeographical analyses. a few highly fit genotypes in each species represent the causative agents for most of the observed disease cases. together, mutational and selective forces create highly adapted pa ... | 2009 | 19820723 |
| environmental and intracellular regulation of francisella tularensis ripa. | francisella tularensis is a highly virulent, facultative intracellular pathogen and the etiologic agent of the zoonotic disease tularemia. ripa is a cytoplasmic membrane protein that is conserved among francisella species and is required for intracellular growth. f. tularensis ripa deletion mutants escape the phagosome of infected cells, but unlike wild type organisms fail to replicate in the host cell cytoplasm. | 2009 | 19821974 |
| aged mice display an altered pulmonary host response to francisella tularensis live vaccine strain (lvs) infections. | aging is a complex phenomenon that has been shown to affect many organ systems including the innate and adaptive immune systems. the current study was designed to examine the potential effect of immunosenescence on the pulmonary immune response using a francisella tularensis live vaccine strain (lvs) inhalation infection model. f. tularensis is a gram-negative intracellular pathogen that can cause a severe pneumonia. in this study both young (8-12 week old) and aged (20-24 month old) mice were i ... | 2010 | 19825409 |
| water-borne outbreak of oropharyngeal and glandular tularemia in georgia: investigation and follow-up. | in november 2006, an outbreak of waterborne tularemia occurred in an eastern region in the republic of georgia. outbreak investigation revealed 26 cases: 21 oropharyngeal and 5 glandular tularemia cases. | 2009 | 19826763 |
| bacillus anthracis, francisella tularensis and yersinia pestis. the most important bacterial warfare agents - review. | there are three most important bacterial causative agents of serious infections that could be misused for warfare purposes: bacillus anthracis (the causative agent of anthrax) is the most frequently mentioned one; however, fracisella tularensis (causing tularemia) and yersinia pestis (the causative agent of plague) are further bacterial agents enlisted by centers for disease control and prevention into the category a of potential biological weapons. this review intends to summarize basic informa ... | 2009 | 19826916 |
| [the time course of changes in cell immunological parameters during administration of live dry plague vaccine]. | the study of the time course of changes in cell immunological parameters by a magnetic separation technique in human beings during the administration of plague vaccine in relation to the immunological load revealed the higher blood levels of all t lymphocyte subpopulations on day 14 after vaccination. these changes are most typical of a primary vaccinated cohort. the increased frequency of plague vaccine administration and multiple immunizations with live plague, anthrax, and tularemia vaccines ... | 2009 | 19827193 |
| development of real-time pcr assays for the specific detection of francisella tularensis ssp. tularensis, holarctica and mediaasiatica. | real-time polymerase chain reaction (pcr) assays were developed to detect francisella tularensis (ft), the causative agent of tularaemia in humans. two real-time pcrs (ftt0376 and ftt0523) were designed in genetic sequences identified by the insignia genome comparison tool (http://insignia.cbcb.umd.edu/) as being unique to pathogenic subspecies of f. tularensis. both pcrs identified all pathogenic f. tularensis subspecies but did not cross react with avirulent francisella philomiragia or f. tula ... | 2010 | 19833196 |
| [identification and characterization of the francisella sp. strain 08hl01032 isolated in air condition systems]. | to identify and characterize the strain 08h101032 was isolated from air condition systems in the routine investigations of legionella in guangzhou, china, in 2008. | 2009 | 19835160 |
| effect of dehydrated storage on the survival of francisella tularensis in infant formula. | francisella tularensis is a gram-negative bacterium that can cause gastrointestinal or oropharyngeal tularemia in humans from ingestion of contaminated food or water. despite the potential for accidental or intentional contamination of foods with f. tularensis, there are few studies on the long-term survivability of this organism in food matrices. infant formula has previously been implicated as a vehicle for the transmission of a variety of bacterial pathogens in infants. in this study, we inve ... | 2009 | 19835784 |
| crystal structures of the histidine acid phosphatase from francisella tularensis provide insight into substrate recognition. | histidine acid phosphatases catalyze the transfer of a phosphoryl group from phosphomonoesters to water at acidic ph using an active-site histidine. the histidine acid phosphatase from the category a pathogen francisella tularensis (fthap) has been implicated in intramacrophage survival and virulence, motivating interest in understanding the structure and mechanism of this enzyme. here, we report a structure-based study of ligand recognition by fthap. the 1.70-a-resolution structure of fthap com ... | 2009 | 19836403 |
| francisella tularensis vaccines. | francisella tularensis has attracted attention historically as a biological weapon, due to its high infectivity in aerosols, and the severity of disease in humans. there is no licensed vaccine currently available, although an attenuated live vaccine strain (lvs) was identified in the middle of the last century and has been successfully used to protect humans. efforts are underway to determine the basis of attenuation of lvs, and to understand the immunity required for protection. alternative app ... | 2009 | 19837286 |
| the presence of cd14 overcomes evasion of innate immune responses by virulent francisella tularensis in human dendritic cells in vitro and pulmonary cells in vivo. | francisella tularensis is a gram-negative bacterium that causes acute, lethal disease following inhalation. we have previously shown that viable f. tularensis fails to stimulate secretion of proinflammatory cytokines following infection of human dendritic cells (hdc) in vitro and pulmonary cells in vivo. here we demonstrate that the presence of the cd14 receptor is critical for detection of virulent f. tularensis strain schus4 by dendritic cells, monocytes, and pulmonary cells. addition of solub ... | 2010 | 19841074 |
| interleukin-17 is required for t helper 1 cell immunity and host resistance to the intracellular pathogen francisella tularensis. | the importance of t helper type 1 (th1) cell immunity in host resistance to the intracellular bacterium francisella tularensis is well established. however, the relative roles of interleukin (il)-12-th1 and il-23-th17 cell responses in immunity to f. tularensis have not been studied. the il-23-th17 cell pathway is critical for protective immunity against extracellular bacterial infections. in contrast, the il-23-th17 cell pathway is dispensable for protection against intracellular pathogens such ... | 2009 | 19853481 |
| acid phosphatases do not contribute to the pathogenesis of type a francisella tularensis. | the intracellular pathogen francisella tularensis is the causative agent of tularemia, a zoonosis that can affect humans with potentially lethal consequences. essential to francisella virulence is its ability to survive and proliferate within phagocytes through phagosomal escape and cytosolic replication. francisella spp. encode a variety of acid phosphatases, whose roles in phagosomal escape and virulence have been documented yet remain controversial. here we have examined in the highly virulen ... | 2010 | 19858304 |
| francisella virulence: significant advances, ongoing challenges and unmet needs. | francisella tularensis, the causative agent of tularemia, is an organism of concern as a potential biowarfare agent. progress towards understanding the molecular basis of pathogenicity has been hampered by a lack of tools with which to manipulate the pathogen. however, the availability of genome sequence data for a range of strains and the development of a range of plasmids and mutagenesis protocols for use in francisella has resulted in a huge advance in understanding. no licensed vaccine is ye ... | 2009 | 19863250 |
| cell biology and molecular ecology of francisella tularensis. | francisella tularensis is a highly infectious intracellular bacterium that causes the fulminating disease tularemia, which can be transmitted between mammals by arthropod vectors. genomic studies have shown that the f. tularensis has been undergoing genomic decay with the most virulent strains having the lowest number of functional genes. entry of f. tularensis into macrophages is mediated by looping phagocytosis and is associated with signalling through syk tyrosine kinase. within macrophages a ... | 2010 | 19863554 |
| possible interaction between a rodenticide treatment and a pathogen in common vole (microtus arvalis) during a population peak. | a common vole (microtus arvalis) population peak in northern spain in 2007 was treated with large scale application of chlorophacinone, an anticoagulant rodenticide of the indandione family. voles found dead and trapped alive were collected in treated and untreated areas. residues of chlorophacinone were analyzed in liver of voles by hplc-uv. also, the presence of the pathogen francisella tularensis was analyzed by pcr in samples of vole spleen. chlorophacinone (82-3800 ng/g; wet weight liver) w ... | 2009 | 19863999 |
| small molecule control of virulence gene expression in francisella tularensis. | in francisella tularensis, the sspa protein family members mgla and sspa form a complex that associates with rna polymerase (rnap) to positively control the expression of virulence genes critical for the intramacrophage growth and survival of the organism. although the association of the mgla-sspa complex with rnap is evidently central to its role in controlling gene expression, the molecular details of how mgla and sspa exert their effects are not known. here we show that in the live vaccine st ... | 2009 | 19876386 |
| utilization of an unstable plasmid and the i-scei endonuclease to generate routine markerless deletion mutants in francisella tularensis. | we engineered an efficient system to make francisella tularensis deletion mutations using an unstable, poorly maintained plasmid to enhance the likelihood of homologous recombination. for counterselection, we adapted a strategy using i-scei, which causes a double-stranded break in the integrated suicide vector, forcing a second recombination to mediate allelic replacement. | 2010 | 19879904 |
| phagosomal retention of francisella tularensis results in tirap/mal-independent tlr2 signaling. | tlr2 plays a central role in the activation of innate immunity in response to ft, the causative agent of tularemia. we reported previously that ft lvs elicited strong, dose-dependent nf-kappab reporter activity in tlr2-expressing human embryo kidney 293 t cells and that ft lvs-induced murine macrophage proinflammatory cytokine gene and protein expression is tlr2-dependent. we demonstrated further that ft can signal through tlr2 from within the phagosome and that phagosomal retention of ft leads ... | 2010 | 19889726 |
| francisella tularensis subsp. novicida isolated from a human in arizona. | francisella tularensis is the etiologic agent of tularemia and is classified as a select agent by the centers for disease control and prevention. currently four known subspecies of f. tularensis that differ in virulence and geographical distribution are recognized:tularensis (type a), holarctica (type b), mediasiatica, and novicida. because of the select agent status and differences in virulence and geographical location, the molecular analysis of any clinical case of tularemia is of particular ... | 2009 | 19895698 |
| gallium disrupts iron uptake by intracellular and extracellular francisella strains and exhibits therapeutic efficacy in a murine pulmonary infection model. | francisella tularensis requires iron (fe) for growth, but the biologic sources of fe for this organism are largely unknown. we found that francisella sp. growing in broth culture or within human macrophages can acquire fe from the two major host fe-binding proteins, lactoferrin (lf) and transferrin (tf). fe acquisition is a potential target for novel therapies. gallium (ga) is a transition metal that interferes with cellular fe metabolism by competing with fe for uptake/utilization. growth of ei ... | 2010 | 19917753 |
| an outbreak of holarctica-type tularemia in pediatric patients. | holarctica-type tularemia is endemic in the northern hemisphere. despite recurrent epidemics tularemia is not well known in children and the pediatric cases are often misdiagnosed. | 2010 | 19918211 |
| vaccines against tularemia. | francisella tularensis is a category a select agent for which vaccine and countermeasure development are a priority. in the past eight years, renewed interest in this pathogen has led to the generation of an enormous amount of new data on both the pathogen itself and its interaction with host cells. this information has fostered the development of various vaccine candidates including acellular subunit, killed whole cell and live attenuated. this review summarizes the progress and promise of thes ... | 2009 | 19923904 |
| regulation of apoptosis and anti-apoptosis signalling by francisella tularensis. | francisella tularensis induces apoptosis within macrophages but the temporal and spatial modulation through activation of caspase-1, caspase-3, and the anti-apoptosis nuclear transcription factor b (nf-kappab) is not known. whether escape of the bacteria into the cytosol is sufficient and/or essential for activation of nf-kappab is not known. our results show that f. tularensis subsp. novicida induces sustained nuclear translocation of nf-kappab at early time points after infection of human mono ... | 2010 | 19925880 |
| restricted cytosolic growth of francisella tularensis subsp. tularensis by ifn-gamma activation of macrophages. | the intracellular bacterium francisella tularensis ensures its survival and proliferation within phagocytes of the infected host through phagosomal escape and cytosolic replication, to cause the disease tularemia. the cytokine interferon-gamma (ifn-gamma) is important in controlling primary infections in vivo, and in vitro intracellular proliferation of francisella in macrophages, but its actual effects on the intracellular cycle of the bacterium are ambiguous. here, we have performed an extensi ... | 2010 | 19926654 |
| interleukin-17 kick-starts t helper 1 cell differentiation. | in this issue of immunity, lin et al. (2009) implicate interleukin-17 in the regulation of t helper 1 (th1) cell immunity against francisella tularensis. these findings add a unique twist to the cytokine regulation of t cell differentiation and function. | 2009 | 19932069 |
| tlr-dependent control of francisella tularensis infection and host inflammatory responses. | francisella tularensis is the causative agent of tularemia and is classified as a category a select agent. recent studies have implicated tlr2 as a critical element in the host protective response to f. tularensis infection, but questions remain about whether tlr2 signaling dominates the response in all circumstances and with all species of francisella and whether f. tularensis pamps are predominantly recognized by tlr2/tlr1 or tlr2/tlr6. to address these questions, we have explored the role of ... | 2009 | 19936231 |
| akt and ship modulate francisella escape from the phagosome and induction of the fas-mediated death pathway. | francisella tularensis infects macrophages and escapes phago-lysosomal fusion to replicate within the host cytosol, resulting in host cell apoptosis. here we show that the fas-mediated death pathway is activated in infected cells and correlates with escape of the bacterium from the phagosome and the bacterial burden. our studies also demonstrate that constitutive activation of akt, or deletion of ship, promotes phago-lysosomal fusion and limits bacterial burden in the host cytosol, and the subse ... | 2009 | 19936232 |
| working toward the future: insights into francisella tularensis pathogenesis and vaccine development. | francisella tularensis is a facultative intracellular gram-negative pathogen and the etiological agent of the zoonotic disease tularemia. recent advances in the field of francisella genetics have led to a rapid increase in both the generation and subsequent characterization of mutant strains exhibiting altered growth and/or virulence characteristics within various model systems of infection. in this review, we summarize the major properties of several francisella species, including f. tularensis ... | 2009 | 19946137 |
| contributions of francisella tularensis subsp. novicida chitinases and sec secretion system to biofilm formation on chitin. | francisella tularensis, the zoonotic cause of tularemia, can infect numerous mammals and other eukaryotes. although studying f. tularensis pathogenesis is essential to comprehending disease, mammalian infection is just one step in the ecology of francisella species. f. tularensis has been isolated from aquatic environments and arthropod vectors, environments in which chitin could serve as a potential carbon source and as a surface for attachment and growth. we show that f. tularensis subsp. novi ... | 2010 | 19948864 |
| mechanisms of bacterial virulence in pulmonary infections. | to consider the relevance to severe human lung infections of recently discovered virulence mechanisms of staphylococcus aureus and francisella tularensis. | 2010 | 19956071 |
| tick-borne agents in rodents, china, 2004-2006. | a total of 705 rodents from 6 provinces and autonomous regions of mainland people's republic of china were tested by pcrs for tick-borne agents (anaplasma phagocytophilum, borrelia burgdorferi sensu lato, spotted fever group rickettsiae, and francisella tularensis). infection rates were 5.5%, 6.7%, 9.1% and 5.0%, respectively. eighteen (2.6%) rodents of 10 species were positive for 2 or 3 agents. sequence analysis of pcr products confirmed the presence and genotypes of detected agents. these fin ... | 2009 | 19961668 |
| landscape epidemiology of tularemia outbreaks in sweden. | summer outbreaks of tularemia that occurred from 1995 through 2005 in 2 locations in sweden affected 441 persons. we performed an epidemiologic investigation of these outbreaks using a novel strategy, involving high-resolution genotyping of francisella tularensis isolates obtained from 136 patients (using 18 genetic markers developed from 6 f. tularensis genome sequences) and interviews with the patients. strong spatial associations were found between f. tularensis subpopulations and the places ... | 2009 | 19961673 |
| identification of francisella tularensis cluster in central and western europe. | we conducted a molecular analysis of francisella tularensis strains isolated in switzerland and identified a specific subpopulation belonging to a cluster of f. tularensis subsp. holarctica that is widely dispersed in central and western continental europe. this subpopulation was present before the tularemia epidemics on the iberian peninsula. | 2009 | 19961699 |
| [pandora's box: pathogens in ixodes ricinus ticks in central europe]. | among the various species of hard ticks, ixodes ricinus is the most frequently found tick throughout europe. as with other ixodid ticks, the developmental cycle runs through three stages. in each stage a blood meal is required in order to develop to the next stage. ixodes ricinus has been found to feed on more than 300 different vertebrate species. usually, larval ticks feed on small mammals such as mice and become infected with various microorganisms and viruses, of which some are substantial p ... | 2009 | 19998007 |
| eradication of intracellular francisella tularensis in thp-1 human macrophages with a novel autophagy inducing agent. | autophagy has been shown recently to play an important role in the intracellular survival of several pathogenic bacteria. in this study, we investigated the effect of a novel small-molecule autophagy-inducing agent, ar-12, on the survival of francisella tularensis, the causative bacterium of tularemia in humans and a potential bioterrorism agent, in macrophages. | 2009 | 20003180 |
| a novel brain heart infusion broth supports the study of common francisella tularensis serotypes. | francisella tularensis schu s4, lvs and u112 have become model organisms for the study of francisella pathogenesis, and represent a cross section of the different f. tularensis subspecies. both schu s4 and lvs are fastidious organisms, requiring medium fortified with supplements and nutrients for enhanced growth. chamberlains defined medium, tryptone soy broth supplemented with cysteine (tsbc), and cation-adjusted mueller-hinton broth (camhb) supplemented with 2% isovitalex are typically used in ... | 2010 | 20005265 |
| identification, cloning, expression, and purification of francisella lpp3: an immunogenic lipoprotein. | the severe and fatal human disease, tularemia, results from infection with the gram-negative pathogen francisella tularensis. identification of surface outer membrane proteins, specifically lipoproteins, has been of interest for vaccine development and understanding the initiation of disease. we sought to identify francisella live vaccine strain lipoproteins that could be a component of a subunit vaccine and have adjuvant properties as tlr2 agonists. we have identified a membrane lipoprotein of ... | 2010 | 20006480 |
| a rapid multiplex assay for nucleic acid-based diagnostics. | we have developed a rapid (under 4 hours), multiplex, nucleic acid assay, adapted to a microsphere array detection platform. we call this assay multiplex oligonucleotide ligation-pcr (mol-pcr). unlike other ligation-based assays that require multiple steps, our protocol consists of a single tube reaction, followed by hybridization to a luminex microsphere array for detection. we demonstrate the ability of this assay to simultaneously detect diverse nucleic acid signatures (e.g., unique sequences ... | 2010 | 20006656 |
| kinetic characterization and phosphoregulation of the francisella tularensis 1-deoxy-d-xylulose 5-phosphate reductoisomerase (mep synthase). | deliberate and natural outbreaks of infectious disease underscore the necessity of effective vaccines and antimicrobial/antiviral therapeutics. the prevalence of antibiotic resistant strains and the ease by which antibiotic resistant bacteria can be intentionally engineered further highlights the need for continued development of novel antibiotics against new bacterial targets. isoprenes are a class of molecules fundamentally involved in a variety of crucial biological functions. mammalian cells ... | 2009 | 20011597 |
| francisella tularensis t-cell antigen identification using humanized hla-dr4 transgenic mice. | there is no licensed vaccine against the intracellular pathogen francisella tularensis. the use of conventional mouse strains to screen protective vaccine antigens may be problematic, given the differences in the major histocompatibility complex (mhc) binding properties between murine and human antigen-presenting cells. we used engineered humanized mice that lack endogenous mhc class ii alleles but that express a human hla allele (hla-dr4 transgenic [tg] mice) to identify potential subunit vacci ... | 2010 | 20016043 |
| differential ability of novel attenuated targeted deletion mutants of francisella tularensis subspecies tularensis strain schu s4 to protect mice against aerosol challenge with virulent bacteria: effects of host background and route of immunization. | francisella tularensis subspecies tularensis is a highly virulent facultative intracellular pathogen of humans and a potential biological weapon. a live vaccine strain, f. tularensis lvs, was developed more than 50 years ago by pragmatic attenuation of a strain of the less virulent holarctica subspecies. lvs was demonstrated to be highly effective in human volunteers who were exposed to intradermal challenge with fully virulent subsp. tularensis, but was less effective against aerosol exposure. ... | 2010 | 20018266 |
| the genome of the amoeba symbiont "candidatus amoebophilus asiaticus" reveals common mechanisms for host cell interaction among amoeba-associated bacteria. | protozoa play host for many intracellular bacteria and are important for the adaptation of pathogenic bacteria to eukaryotic cells. we analyzed the genome sequence of "candidatus amoebophilus asiaticus," an obligate intracellular amoeba symbiont belonging to the bacteroidetes. the genome has a size of 1.89 mbp, encodes 1,557 proteins, and shows massive proliferation of is elements (24% of all genes), although the genome seems to be evolutionarily relatively stable. the genome does not encode pat ... | 2010 | 20023027 |
| assessment of low-molecular-weight antioxidants in francisella tularensis infected hosts: comparison of two rodents with different susceptibility to tularemia. | bacterium francisella tularensis is the causative agent of tularemia disease. it is a zoonosis accompanied with high mortality when untreated. small rodents and hares, in particular, are natural reservoirs of tularemia. despite physiological similarity of common hosts, tularemia exerts different mortality rates. the pathogenesis of tularemia is still not fully understood. the main pathway is associated with proliferation in macrophages after activation by reactive oxygen species in phagosomes. | 2009 | 20027169 |
| genome sequence of the endosymbiont rickettsia peacockii and comparison with virulent rickettsia rickettsii: identification of virulence factors. | rickettsia peacockii, also known as the east side agent, is a non-pathogenic obligate intracellular bacterium found as an endosymbiont in dermacentor andersoni ticks in the western usa and canada. its presence in ticks is correlated with reduced prevalence of rickettsia rickettsii, the agent of rocky mountain spotted fever. it has been proposed that a virulent sfg rickettsia underwent changes to become the east side agent. we determined the genome sequence of r. peacockii and provide a compariso ... | 2009 | 20027221 |
| a real-time pcr array for hierarchical identification of francisella isolates. | a robust, rapid and flexible real-time pcr assay for hierarchical genetic typing of clinical and environmental isolates of francisella is presented. typing markers were found by multiple genome and gene comparisons, from which 23 canonical single nucleotide polymorphisms (cansnps) and 11 canonical insertion-deletion mutations (canindels) were selected to provide phylogenetic guidelines for classification from genus to isolate level. the specificity of the developed assay, which uses 68 wells of ... | 2009 | 20027310 |
| a tolc mutant of francisella tularensis is hypercytotoxic compared to the wild type and elicits increased proinflammatory responses from host cells. | the highly infectious bacterium francisella tularensis is a facultative intracellular pathogen and the causative agent of tularemia. tolc, which is an outer membrane protein involved in drug efflux and type i protein secretion, is required for the virulence of the f. tularensis live vaccine strain (lvs) in mice. here, we show that an lvs deltatolc mutant colonizes livers, spleens, and lungs of mice infected intradermally or intranasally, but it is present at lower numbers in these organs than in ... | 2010 | 20028804 |
| inhibition of acpa phosphatase activity with ascorbate attenuates francisella tularensis intramacrophage survival. | acid phosphatase activity in the highly infectious intracellular pathogen francisella tularensis is directly related with the ability of these bacteria to survive inside host cells. pharmacological inactivation of acid phosphatases could potentially help in the treatment of tularemia or even be utilized to neutralize the infection. in the present work, we report inhibitory compounds for three of the four major acid phosphatases produced by f. tularensis schu4: acpa, acpb, and acpc. the inhibitor ... | 2010 | 20028980 |
| real-time pcr for diagnosis of oculoglandular tularemia. | 2010 | 20031067 | |
| the unraveling panoply of francisella tularensis virulence attributes. | francisella tularensis is a highly infectious gram-negative bacterium causing the zoonotic disease tularemia. this facultative intracellular pathogen multiplies in vivo mainly inside macrophages, but has the capacity to infect and survive in many other cell types, including other phagocytic and nonphagocytic cells. in vitro, f. tularensis escapes rapidly from the phagosomal compartment and replicates in the cytoplasm of infected cells. an impressive number of novel genes related to f. tularensis ... | 2010 | 20034843 |
| mir-155 induction by f. novicida but not the virulent f. tularensis results in ship down-regulation and enhanced pro-inflammatory cytokine response. | the intracellular gram-negative bacterium francisella tularensis causes the disease tularemia and is known for its ability to subvert host immune responses. previous work from our laboratory identified the pi3k/akt pathway and ship as critical modulators of host resistance to francisella. here, we show that ship expression is strongly down-regulated in monocytes and macrophages following infection with f. tularensis novicida (f.n.). to account for this negative regulation we explored the possibi ... | 2009 | 20041145 |
| attenuation of the fish pathogen francisella sp. by mutation of the iglc* gene. | fish francisellosis is an emergent disease caused by gram-negative facultative intracellular bacteria of the genus francisella. different strains of the bacterium have caused high mortalities in warmwater and coldwater fish species. francisella sp. isolates from fish have been found to share more than 97% identity to the human pathogen francisella tularensis upon 16s ribosomal rna sequence comparison. homologue genes of the f. tularensis intracellular growth locus (igla*, iglb*, iglc*, and igld* ... | 2009 | 20043398 |
| pathological and microbiological studies of japanese hare (lepus brachyurus angustidens) naturally infected with francisella tularensis subsp. holarctica. | an adult male hare (lepus brachyurus angustidens) was discovered in a moribund condition in the bush in the mountains of aomori prefecture in japan. upon gross inspection, many ticks were found on the neck and the external ear regions, and more than half the ticks contained blood in the intestine. the skin around the tick bite wounds was alopecic and mildly thickened. at necropsy, enlargement of the cervical lymph nodes and spleen were observed. histologically, acute necrotizing splenitis, lymph ... | 2009 | 20046031 |
| the francisella tularensis pathogenicity island encodes a secretion system that is required for phagosome escape and virulence. | francisella tularensis causes the human disease tularemia. f. tularensis is able to survive and replicate within macrophages, a trait that has been correlated with its high virulence, but it is unclear the exact mechanism(s) this organism uses to escape killing within this hostile environment. f. tularensis virulence is dependent upon the francisella pathogenicity island (fpi), a cluster of genes that we show here shares homology with type vi secretion gene clusters in vibrio cholerae and pseudo ... | 2009 | 20054881 |
| [the lipoolygosaccharide o-antigen of francisella tularensis]. | 2009 | 20063802 | |
| statistical assessment of dna extraction reagent lot variability in real-time quantitative pcr. | the aim of this study was to evaluate the variability in lots of a dna extraction kit using real-time pcr assays for bacillus anthracis, francisella tularensis and vibrio cholerae. | 2010 | 20070509 |
| the effect of interferon-gamma and lipopolysaccharide on the growth of francisella tularensis lvs in murine macrophage-like cell line j774. | francisella tularensis, a causative agent of human tularemia, displaying the ability to proliferate inside the human cells. | 2009 | 20073421 |
| modulation of hepatic ppar expression during ft lvs lps-induced protection from francisella tularensis lvs infection. | it has been shown previously that administration of francisella tularensis (ft) live vaccine strain (lvs) lipopolysaccharide (lps) protects mice against subsequent challenge with ft lvs and blunts the pro-inflammatory cytokine response. | 2010 | 20082697 |
| identification of ciprofloxacin resistance by simpleprobe, high resolution melt and pyrosequencing nucleic acid analysis in biothreat agents: bacillus anthracis, yersinia pestis and francisella tularensis. | the potential for genetic modification of biological warfare agents makes rapid identification of antibiotic resistant strains critical for the implementation of suitable infection control measures. the fluorinated quinolone, ciprofloxacin, is an antibiotic effective for treating bacterial infections by inhibiting the enzyme activity of the dna type ii topoisomerases dna gyrase and topoisomerase iv. the genes that encode the subunits of dna gyrase (gyra and gyrb) and topo iv (par c and pare) con ... | 2010 | 20100564 |
| insect infection model for campylobacter jejuni reveals that o-methyl phosphoramidate has insecticidal activity. | galleria mellonella (wax moth) larvae have elsewhere been shown to be susceptible to pathogens such as francisella tularensis, burkholderia mallei, and pseudomonas aeruginosa. we report that the larvae are rapidly killed by campylobacter jejuni at 37c. three strains of c. jejuni tested, 11168h (human diarrheal isolate), g1 (human guillain-barré syndrome isolate), and 81-176 (human diarrheal isolate), were equally effective at killing g. mellonella larvae. a panel of defined mutants of c. jejuni ... | 2010 | 20113177 |
| investigating an airborne tularemia outbreak, germany. | in november 2005, an outbreak of tularemia occurred among 39 participants in a hare hunt in hesse, germany. previously reported tularemia outbreaks in germany dated back to the 1950s. we conducted a retrospective cohort study among participants and investigated the environment to identify risk factors for infection. ten participants had serologic evidence of acute francisella tularensis infection; 1 other participant died before laboratory confirmation was obtained. presence within 5 meters of t ... | 2010 | 20113553 |
| [rabbit fever--a neck tumor]. | twenty-two-year-old previously healthy male is referred to the ent clinic with a neck tumour. the patient was an animal caretaker. ultrasonic examination showed a lymph gland conglomerate on the left side of the neck. primary serologic examination was negative and the lymph tumour was removed. the biopsy showed necrotic lymphadenitis. three weeks after the first consultation the patient tests positive for f. tularensis. the patient was treated with ciprofloxacin 750 mg x 2 by the oral route for ... | 2010 | 20122334 |