| deep mitochondrial dna lineage divergences within alberta populations of dermacentor albipictus (acari: ixodidae) do not indicate distinct species. | the winter tick dermacentor albipictus (packard) has a single-host life cycle that allows it to reach severe infestation levels on ungulates, particularly moose. genotypic variation within these and related ticks has been a source of taxonomic confusion, although the continuity in their morphology and life history has generally been interpreted as indicating the existence of a single species. to further investigate this variation, we sequenced regions of two mitochondrial dna (mtdna) genes (coi ... | 2010 | 20695271 |
| detection of francisella tularensis in alaskan mosquitoes (diptera: culicidae) and assessment of a laboratory model for transmission. | tularemia is a zoonotic disease caused by the category a bioterrorism agent francisella tularensis. in scandinavia, tularemia transmission by mosquitoes has been widely cited in the literature. we tested >2,500 mosquitoes captured in alaska and found francisella dna in 30% of pooled samples. to examine the potential for transmission of francisella by mosquitoes, we developed a mosquito model of francisella infection. larvae of anopheles gambiae giles and aedes aegypti (l.) readily ingest f. tula ... | 2010 | 20695280 |
| the fsle homolog, ftl_0439 (fupa/b), mediates siderophore-dependent iron uptake in francisella tularensis lvs. | the gram-negative pathogen francisella tularensis secretes a siderophore to obtain essential iron by a tonb-independent mechanism. the fslabcde locus, encoding siderophore-related functions, is conserved among different francisella strains. in the virulent strain schu s4, fsle is essential for siderophore utilization and for growth under conditions of iron limitation. in contrast, we found that deletion of fsle did not affect siderophore utilization by the attenuated live vaccine strain (lvs). w ... | 2010 | 20696823 |
| histologic, immunohistochemical, microbiological, molecular biological and ultrastructural characterization of pulmonary tularemia. | tularemia is a rare zoonotic disease caused by francisella tularensis, a gram-negative bacteria. the clinical manifestations of pulmonary tularemia resemble those of other airways infections. recently, a case of pulmonary tularemia was diagnosed at tufts medical center. the purpose of the current report is to document the utility of applying several diagnostic tools, including immunohistochemistry, electron microscopy, microbiology and molecular biology in confirming the diagnosis of pulmonary t ... | 2011 | 20709464 |
| the human-bacterial pathogen protein interaction networks of bacillus anthracis, francisella tularensis, and yersinia pestis. | bacillus anthracis, francisella tularensis, and yersinia pestis are bacterial pathogens that can cause anthrax, lethal acute pneumonic disease, and bubonic plague, respectively, and are listed as niaid category a priority pathogens for possible use as biological weapons. however, the interactions between human proteins and proteins in these bacteria remain poorly characterized leading to an incomplete understanding of their pathogenesis and mechanisms of immune evasion. | 2010 | 20711500 |
| in vitro and in vivo efficacy of florfenicol for treatment of francisella asiatica infection in tilapia. | francisella asiatica is a recently described, gram-negative, facultative intracellular fish pathogen, known to be the causative agent of francisellosis in warm-water fish. francisellosis outbreaks have increased in frequency among commercial aquaculture operations and have caused severe economic losses in every case reported. the lack of effective treatments for piscine francisellosis led us to investigate the potential efficacy of florfenicol for inhibition of f. asiatica in vitro and as an ora ... | 2010 | 20713674 |
| coexistence of pathogens in host-seeking and feeding ticks within a single natural habitat in central germany. | the importance of established and emerging tick-borne pathogens in central and northern europe is steadily increasing. in 2007, we collected ixodes ricinus ticks feeding on birds (n = 211) and rodents (n = 273), as well as host-seeking stages (n = 196), in a habitat in central germany. in order to find out more about their natural transmission cycles, the ticks were tested for the presence of lyme disease borreliae, anaplasma phagocytophilum, spotted fever group (sfg) rickettsiae, francisella tu ... | 2010 | 20729315 |
| systems approach to investigating host-pathogen interactions in infections with the biothreat agent francisella. constraints-based model of francisella tularensis. | francisella tularensis is a prototypic example of a pathogen for which few experimental datasets exist, but for which copious high-throughout data are becoming available because of its re-emerging significance as biothreat agent. the virulence of francisella tularensis depends on its growth capabilities within a defined environmental niche of the host cell. | 2010 | 20731870 |
| escherichia coli mutants that synthesize dephosphorylated lipid a molecules. | the lipid a moiety of escherichia coli lipopolysaccharide is a hexaacylated disaccharide of glucosamine that is phosphorylated at the 1 and 4' positions. expression of the francisella novicida lipid a 1-phosphatase fnlpxe in e. coli results in dephosphorylation of the lipid a proximal unit. coexpression of fnlpxe and the rhizobium leguminosarum lipid a oxidase rllpxq in e. coli converts much of the proximal glucosamine to 2-amino-2-deoxygluconate. expression of the f. novicida lipid a 4'-phospha ... | 2010 | 20795687 |
| the type iv pilin, pila, is required for full virulence of francisella tularensis subspecies tularensis. | all four francisella tularensis subspecies possess gene clusters with potential to express type iv pili (tfp). these clusters include putative pilin genes, as well as pilb, pilc and pilq, required for secretion and assembly of tfp. a hallmark of tfp is the ability to retract the pilus upon surface contact, a property mediated by the atpase pilt. interestingly, out of the two major human pathogenic subspecies only the highly virulent type a strains have a functional pilt gene. | 2010 | 20796283 |
| 3-deoxy-d-manno-octulosonic acid (kdo) hydrolase identified in francisella tularensis, helicobacter pylori, and legionella pneumophila. | 3-deoxy-d-manno-octulosonic acid (kdo) is an eight-carbon sugar ubiquitous in gram-negative bacterial lipopolysaccharides (lps). although its biosynthesis is well described, no protein has yet been identified as a kdo hydrolase. however, kdo hydrolase enzymatic activity has been detected in membranes of helicobacter pylori and francisella tularensis and may be responsible for the removal of side-chain kdo from the lps core saccharides. we now report the identification of genes encoding a kdo hyd ... | 2010 | 20801884 |
| transmission dynamics of francisella tularensis subspecies and clades by nymphal dermacentor variabilis (acari: ixodidae). | in the united states, the american dog tick, dermacentor variabilis (say) is considered an important biological vector of francisella tularensis, the etiologic agent of tularemia. in this study, we evaluated the vector efficiency of nymphal d. variabilis infected as larvae with differing clades and subspecies (a1b, a2, and type b) of f. tularensis. in all cases, d. variabilis larvae were able to acquire, maintain, and transstadially transmit f. tularensis. significant replication of the bacteria ... | 2010 | 20810833 |
| matrix-assisted laser desorption ionization time-of-flight mass spectrometry: usefulness for taxonomy and epidemiology. | matrix-assisted laser desorption ionization time-of-flight (maldi-tof) mass spectrometry (ms) is a powerful tool for the species and subspecies classification of a broad spectrum of bacteria, including gram-positive bacteria such as staphylococcus, streptococcus and listeria, and gram-negative bacteria such as neisseria, salmonella, aeromonas, campylobacter and helicobacter. maldi-tof ms has also been used for the rapid identification and typing of potential bioterrorism agents, including coxiel ... | 2010 | 20825435 |
| phenotypic and genetic characterization of macrolide resistance in francisella tularensis subsp. holarctica biovar i. | francisella tularensis subsp. holarctica strains are classified as biovars i and ii, which are susceptible and naturally resistant to the macrolide erythromycin, respectively. the present study was aimed at both selecting biovar i strains with increased levels of erythromycin resistance and characterizing the underlying genetic mechanisms. | 2010 | 20837574 |
| versatile set of orthogonal protecting groups for the preparation of highly branched oligosaccharides. | a new set of orthogonal protecting groups has been developed based on the use of a diethylisopropylsilyl (deips), methylnaphthyl (nap), allyl ether, and levulinoyl (lev) ester. the protecting groups are ideally suited for the preparation of highly branched oligosaccharides and their usefulness has been demonstrated by the chemical synthesis of a β-d-man-(1→4)-d-man disaccharide, which is appropriately protected for making a range of part-structures of the unusual core region of the lipopolysacch ... | 2010 | 20845911 |
| tick-borne disease agents in various wildlife from mississippi. | because tick-borne diseases are becoming increasingly important throughout the world, monitoring their causative agents in wildlife may serve as a useful indicator of potential human exposure. we assessed the presence of known and putative zoonotic, tick-borne agents in four wildlife species in mississippi. animals were tested for exposure to or infection with ehrlichia chaffeensis, ehrlichia ewingii, borrelia lonestari, rickettsia spp., anaplasma phagocytophilum, and francisella tularensis. who ... | 2011 | 20846016 |
| tularaemia outbreaks in sakarya, turkey: case-control and environmental studies. | tularaemia is an important zoonotic disease that leads to outbreaks. this study aimed to compare the epidemiological characteristics of two tularaemia outbreaks that occurred in the sakarya region of turkey, analyse the risk factors for the development of outbreaks and identify francisella (f.) tularensis in the water samples. | 2010 | 20848064 |
| mast cell/il-4 control of francisella tularensis replication and host cell death is associated with increased atp production and phagosomal acidification. | mast cells are now recognized as effective modulators of innate immunity. we recently reported that mast cells and secreted interleukin-4 (il-4) effectively control intramacrophage replication of francisella tularensis live vaccine strain (lvs), and that mice deficient in mast cells or il-4 receptor (il-4r(-/-)) exhibit greater susceptibility to pulmonary challenge. in this study, we further evaluated the mechanism(s) by which mast cells/il-4 control intramacrophage bacterial replication and hos ... | 2011 | 20861832 |
| reciprocal analysis of francisella novicida infections of a drosophila melanogaster model reveal host-pathogen conflicts mediated by reactive oxygen and imd-regulated innate immune response. | the survival of a bacterial pathogen within a host depends upon its ability to outmaneuver the host immune response. thus, mutant pathogens provide a useful tool for dissecting host-pathogen relationships, as the strategies the microbe has evolved to counteract immunity reveal a host's immune mechanisms. in this study, we examined the pathogen francisella novicida and identified new bacterial virulence factors that interact with different parts of the drosophila melanogaster innate immune system ... | 2010 | 20865166 |
| simultaneous pathogen detection and antibiotic resistance characterization using snp-based multiplexed oligonucleotide ligation-pcr (mol-pcr). | extensive use of antibiotics in both public health and animal husbandry has resulted in rapid emergence of antibiotic resistance in almost all human pathogens, including biothreat pathogens. antibiotic resistance has thus become a major concern for both public health and national security. we developed multiplexed assays for rapid, simultaneous pathogen detection and characterization of ciprofloxacin and doxycycline resistance in bacillus anthracis, yersinia pestis, and francisella tularensis. t ... | 2010 | 20865530 |
| analysis of lipids from crude lung tissue extracts by desorption electrospray ionization mass spectrometry and pattern recognition. | a method is described using desorption electrospray ionization (desi) mass spectrometry (ms) to obtain phospholipid mass spectral profiles from crude lung tissue extracts. the measured desi mass spectral lipid fingerprints were then analyzed by unsupervised learning principal components analysis (pca). this combined approach was used to differentiate the effect(s) of two vaccination routes on lipid composition in mouse lungs. specifically, the two vaccination routes compared were intranasal (i.n ... | 2010 | 20868645 |
| [preparation of magnetic latexes and their use for the immunodetection of microbial antigens]. | the possibility of detecting antigens of plague, tularemia, and brucellosis microbes with magnetic latex (ml)-based test systems has been demonstrated. mls were prepared from latexes (polyacroleine microspheres, 1.2-1.8 +/- 0.1 microm) by exposing the particles to a 25-35%-solution of ferrous sulfate for 0.5 h and then to a 15-25%-aqueous solution of ammonia for 0.5 h in a 100 degrees c water bath and dehydrating after each operation. the possibility of preparing magnetic latex immunosorbents (m ... | 2010 | 20873177 |
| molecular detection of persistent francisella tularensis subspecies holarctica in natural waters. | tularemia, caused by the bacterium francisella tularensis, where f. tularensis subspecies holarctica has long been the cause of endemic disease in parts of northern sweden. despite this, our understanding of the natural life-cycle of the organism is still limited. during three years, we collected surface water samples (n = 341) and sediment samples (n = 245) in two areas in sweden with endemic tularemia. real-time pcr screening demonstrated the presence of f. tularenis lpna sequences in 108 (32% ... | 2010 | 20885922 |
| effects of the putative transcriptional regulator iclr on francisella tularensis pathogenesis. | francisella tularensis is a highly virulent gram-negative bacterium and is the etiological agent of the disease tularemia. iclr, a presumed transcriptional regulator, is required for full virulence of the animal pathogen, f. tularensis subspecies novicida u112 (53). in this study, we investigated the contribution of iclr to the intracellular growth, virulence, and gene regulation of human pathogenic f. tularensis subspecies. deletion of iclr from the live vaccine strain (lvs) and schus4 strain o ... | 2010 | 20921148 |
| deletion of ripa alleviates suppression of the inflammasome and mapk by francisella tularensis. | francisella tularensis is a facultative intracellular pathogen and potential biothreat agent. evasion of the immune response contributes to the extraordinary virulence of this organism although the mechanism is unclear. whereas wild-type strains induced low levels of cytokines, an f. tularensis ripa deletion mutant (lvsδripa) provoked significant release of il-1β, il-18, and tnf-α by resting macrophages. il-1β and il-18 secretion was dependent on inflammasome components pyrin-caspase recruitment ... | 2010 | 20921527 |
| a review of sentinel laboratory performance: identification and notification of bioterrorism agents. | the anthrax incident of 2001 in the united states prompted the college of american pathologists (cap), the association of public health laboratories, and the centers for disease control and prevention to develop exercises for laboratory response network (lrn) sentinel laboratories. | 2010 | 20923306 |
| [tularemia]. | | 2010 | 20942053 |
| case records of the massachusetts general hospital. case 31-2010. a 29-year-old woman with fever after a cat bite. | | 2010 | 20942673 |
| enhancement of deoxyribonucleic acid microarray performance using post-hybridization signal amplification. | microarray performance depends upon the ability to screen samples against a vast array of probes with the appropriate sensitivity and selectivity. while these factors are significantly influenced by probe design, they are also subject to the particular detection methodology and reagents employed. herein we describe the incorporation of super avidin-biotin system (sabs) and secondary enzymatic enhancement (see) as post-hybridization signal amplification techniques to improve the sensitivity of ol ... | 2010 | 20951861 |
| susceptibility of the common hamster (cricetus cricetus) to francisella tularensis and its effect on the epizootiology of tularemia in an area where both are endemic. | francisella tularensis is a highly infectious zoonotic agent causing the disease tularemia. the common hamster (cricetus cricetus) is considered a pest in eastern europe, and believed to be a source of human tularemia infections. we examined the role of the common hamster in the natural cycle of tularemia using serologic methods on 900 hamsters and real-time polymerase chain reaction (pcr) on 100 hamsters in an endemic agricultural area. we collected 374 ixodes acuminatus ticks from the hamsters ... | 2010 | 20966287 |
| molecular immune responses to aerosol challenge with francisella tularensis in mice inoculated with live vaccine candidates of varying efficacy. | francisella tularensis is a facultative intracellular bacterial pathogen and the etiological agent of tularemia. the subspecies f. tularensis tularensis is especially virulent for humans when inhaled and respiratory tularemia is associated with high mortality if not promptly treated. a live vaccine strain (lvs) derived from the less virulent holarctica subspecies confers incomplete protection against aerosol challenge with subsp. tularensis. moreover, correlates of protection have not been estab ... | 2010 | 20967278 |
| francisella philomiragia biofilm formation and interaction with the aquatic protist acanthamoeba castellanii. | the bacterium francisella philomiragia has been isolated from environmental samples originating from around the globe. f. philomiragia-related strains cause francisellosis of both farmed and wild fish. in addition, occasional human infections caused by f. philomiragia are found in victims of near-drowning and patients with chronic granulomatous disease. we have shown that f. philomiragia forms in vitro biofilms with increased formation at 25 °c over 37 °c conditions. we found that f. philomiragi ... | 2010 | 20972262 |
| new vector tools with a hygromycin resistance marker for use with opportunistic pathogens. | the ability of many bacterial strains to tolerate antibiotics can limit the number of molecular tools available for research of these organisms. to help address this problem, we have modified a diverse set of vectors to include a broadly expressed hygromycin resistance (hmr) marker. hygromycin b is an aminoglycoside antibiotic not used to treat infections in humans and has antimicrobial activity against a wide range of microorganisms. vectors with four replication origins are represented, with p ... | 2011 | 20972648 |
| monitoring the survival of fish-pathogenic francisella in water microcosms. | in this report, the survival behaviour of fish pathogenic francisella in water microcosms was investigated under laboratory conditions. two isolates of francisella noatunensis (ncimb14265(t) and pq 1106), from fish held in seawater and freshwater, were inoculated into natural (nonsterile) and sterile sea- and freshwater microcosms, respectively, and monitored under different temperature conditions (4, 8 and 12 °c) over a period of 60 days. the culturability of the strains was inversely related t ... | 2010 | 20977492 |
| determination of francisella tularensis acpb acid phosphatase substrate preferences. | the francisella species encode 4 main acid phosphatases (acp) that are potentially involved in pathogenesis through currently unknown mechanisms. only 2 of these enzymes, acpa and acpc, have been biochemically characterized to date. in this work we describe the catalytic properties of francisella tularensis acpb utilizing an array of 120 phosphorylated substrates. in contrast to most acid phosphatases, the purified enzyme showed a narrow range of substrate preferences, with the highest affinity ... | 2010 | 21042033 |
| structure of the francisella tularensis enoyl-acyl carrier protein reductase (fabi) in complex with nad(+) and triclosan. | enoyl-acyl carrier protein reductase (fabi) catalyzes the last rate-limiting step in the elongation cycle of the fatty-acid biosynthesis pathway and has been validated as a potential antimicrobial drug target in francisella tularensis. the development of new antibiotic therapies is important both to combat potential drug-resistant bioweapons and to address the broader societal problem of increasing antibiotic resistance among many pathogenic bacteria. the crystal structure of fabi from f. tulare ... | 2010 | 21045289 |
| comparative proteomic profiling of culture filtrate proteins of less and highly virulent francisella tularensis strains. | the facultative intracellular bacterium francisella tularensis is the causal agent of the serious infectious disease tularemia. despite the dynamic progress, which has been made in last few years, important questions regarding francisella pathogenicity still remain to be answered. generally, secreted proteins play an important role in pathogenicity of intracellular microbes. in this study, we investigated the protein composition of the culture filtrate proteins of highly virulent f. tularensis s ... | 2010 | 21061425 |
| [an oropharyngeal tularemia case diagnosed by the isolation of francisella tularensis on human blood agar]. | tularemia which is a multisystem disease of humans and some animals, is endemic in north america, some parts of europe and asia. the causative agent, francisella tularensis, is a fastidious gram-negative, intracellular bacterium which requires supplementation with sulphydryl compounds (cysteine, cystine, thiosulphate, isovitalex) for growth on common laboratory media. in this report, a case of oropharyngeal tularemia diagnosed by the isolation of the causative agent on non-selective-common micro ... | 2010 | 21063979 |
| identification of small rnas in francisella tularensis. | regulation of bacterial gene expression by small rnas (srnas) have proved to be important for many biological processes. francisella tularensis is a highly pathogenic gram-negative bacterium that causes the disease tularaemia in humans and animals. relatively little is known about the regulatory networks existing in this organism that allows it to survive in a wide array of environments and no srna regulators have been identified so far. | 2010 | 21067590 |
| genetic identification of unique immunological responses in mice infected with virulent and attenuated francisella tularensis. | francisella tularensis is a category a select agent based on its infectivity and virulence but disease mechanisms in infection remain poorly understood. murine pulmonary models of infection were therefore employed to assess and compare dissemination and pathology and to elucidate the host immune response to infection with the highly virulent type a f. tularensis strain schu4 versus the less virulent type b live vaccine strain (lvs). we found that dissemination and pathology in the spleen was sig ... | 2010 | 21070859 |
| coexistence of emerging bacterial pathogens in ixodes ricinus ticks in serbia. | the list of tick-borne pathogens is long, varied and includes viruses, bacteria, protozoa and nematodes. as all of these agents can exist in ticks, their co-infections have been previously reported. we studied co-infections of emerging bacterial pathogens (borrelia burgdorferi sensu lato, anaplasma phagocytophilum and francisella tularensis) in ixodes ricinus ticks in serbia. using pcr technique, we detected species-specific sequences, rrf-rrl rdna intergenic spacer for b. burgdorferi s.l., p44/ ... | 2010 | 21073144 |
| the calcineurin inhibitor rcan1 is involved in cultured macrophage and in vivo immune response. | studies on the role of regulator of calcineurin 1 (rcan1) in immunity are limited, but have demonstrated an involvement in t-lymphocyte function. here, we expand these studies to macrophages and in vivo infection. the treatment of raw and primary mouse macrophages with lipopolysaccharide from escherichia coli strongly induced rcan1 isoform 4 (rcan1-4), but not isoform 1. rcan1-4 induction involved calcium, calcineurin, and reactive oxygen species. subsequent analysis with whole bacteria includin ... | 2010 | 21073546 |
| francisella tularensis schu s4 o-antigen and capsule biosynthesis gene mutants induce early cell death in human macrophages. | francisella tularensis is capable of rampant intracellular growth and causes a potentially fatal disease in humans. whereas many mutational studies have been performed with avirulent strains of francisella, relatively little has been done with strains that cause human disease. we generated a near-saturating transposon library in the virulent strain schu s4, which was subjected to high-throughput screening by transposon site hybridization through primary human macrophages, negatively selecting 20 ... | 2010 | 21078861 |
| a bacterial two-hybrid system that utilizes gateway cloning for rapid screening of protein-protein interactions. | comprehensive clone sets representing the entire genome now exist for a large number of organisms. the gateway entry clone sets are a particularly useful means to study gene function, given the ease of introduction into any gateway-suitable destination vector. we have adapted a bacterial two-hybrid system for use with gateway entry clone sets, such that potential interactions between proteins encoded within these clone sets can be determined by new destination vectors. we show that utilizing the ... | 2010 | 21091448 |
| phosphatidylinositol 3-kinase activation attenuates the tlr2-mediated macrophage proinflammatory cytokine response to francisella tularensis live vaccine strain. | an inadequate innate immune response appears to contribute to the virulence of francisella tularensis following pulmonary infection. studies in mice suggest that this poor response results from suppression of proinflammatory cytokine production early during infection, but the mechanisms involved are not understood. pi3k is known to regulate proinflammatory cytokine expression, but its exact role (positive versus negative) is controversial. we sought to clarify the role of pi3k in regulating proi ... | 2010 | 21098227 |
| detection of a novel subspecies of francisella noatunensis as endosymbiont of the ciliate euplotes raikovi. | francisella are facultative intracellular bacteria causing severe disease in a broad range of animals. two species are notable: francisella tularensis, the causative organism of tularemia and a putative warfare agent, and francisella noatunensis, an emerging fish pathogen causing significant losses in wild and farmed fish. although various aspects of francisella biology have been intensively studied, their natural reservoir in periods between massive outbreaks remains mysterious. protists have b ... | 2010 | 21110016 |
| quantification of the relationship between bacterial kinetics and host response for monkeys exposed to aerosolized francisella tularensis. | francisella tularensis can be disseminated via aerosols, and once inhaled, only a few microorganisms may result in tularemia pneumonia. effective responses to this threat depend on a thorough understanding of the disease development and pathogenesis. in this study, a class of time-dose-response models was expanded to describe quantitatively the relationship between the temporal probability distribution of the host response and the in vivo bacterial kinetics. an extensive literature search was co ... | 2010 | 21115714 |
| rabbit tularemia and hepatic coccidiosis in wild rabbit. | | 2010 | 21122253 |
| attenuated response of aged mice to respiratory francisella novicida is characterized by reduced cell death and absence of subsequent hypercytokinemia. | pneumonia and pulmonary infections are major causes of mortality among the growing elderly population. age associated attenuations of various immune parameters, involved with both innate and adaptive responses are collectively known as immune senescence. these changes are likely to be involved with differences in host susceptibility to disease between young and aged individuals. | 2010 | 21124895 |
| molecular diagnosis of francisellosis, a systemic granulomatous inflammatory disease in atlantic cod, gadus morhua l. | a pcr-based assay for the detection of francisella noatunensis causing francisellosis in atlantic cod, gadus morhua has been developed. seven sets of primers targeting the flanking regions of the genes (rpoa, sdha, atpa, rpob, pgm, groel and 16s rrna) of the pathogen were designed. among the primers, groel was found to be the most suitable gene candidate for detecting the pathogen, due to its high sensitivity at various annealing temperatures and specificity in detection. the detection limit of ... | 2010 | 21125329 |
| protection afforded by fluoroquinolones in animal models of respiratory infections with bacillus anthracis, yersinia pestis, and francisella tularensis. | successful treatment of inhalation anthrax, pneumonic plague and tularemia can be achieved with fluoroquinolone antibiotics, such as ciprofloxacin and levofloxacin, and initiation of treatment is most effective when administered as soon as possible following exposure. bacillus anthracis ames, yersinia pestis co92, and francisella tularensis schu s4 have equivalent susceptibility in vitro to ciprofloxacin and levofloxacin (minimal inhibitory concentration is 0.03 μg/ml); however, limited informat ... | 2010 | 21127743 |
| the intracellular lifestyle of francisella noatunensis in atlantic cod (gadus morhua l.) leucocytes. | francisella noatunensis causes the systemic granulomatous inflammatory disease, francisellosis in cod. little is known about the lifestyle of this facultative intracellular bacterium within cod leucocytes. we have examined the interaction of this bacterium with phagocytic cells isolated from cod with emphasis on monocytes, macrophages, neutrophils and phagocytic b-cells. it is clear from confocal microscopy sections through adherent cell preparations that numerous bacteria were located intracell ... | 2010 | 21129488 |
| survival of francisella tularensis type a in brackish-water. | martha's vineyard (mv), massachusetts has been the location of two outbreaks of pneumonic tularemia; landscaping activities have been associated with risk, suggesting environmental inhalation exposure. we determined whether salinity or other components of brackish-water present in a location with endemic tularemia may prolong survival of f. tularensis. in addition, we demonstrate for the first time that f. tularensis type a appears similar to type b with respect to environmental stability. the r ... | 2010 | 21136042 |
| comparative proteomic profiling of culture filtrate proteins of less and highly virulent francisella tularensis strains. | the facultative intracellular bacterium francisella tularensis is the causal agent of the serious infectious disease tularemia. despite the dynamic progress, which has been made in last few years, important questions regarding francisella pathogenicity still remain to be answered. generally, secreted proteins play an important role in pathogenicity of intracellular microbes. in this study, we investigated the protein composition of the culture filtrate proteins of highly virulent f. tularensis s ... | 2010 | 21136602 |
| proteomic characterization and functional analysis of outer membrane vesicles of francisella novicida suggests possible role in virulence and use as a vaccine. | we have isolated and characterized outer membrane vesicles (omvs) from francisella. transport of effector molecules through secretion systems is a major mechanism by which francisella tularensis alters the extracellular proteome and interacts with the host during infection. outer membrane vesicles produced by francisella were examined using tem and afm and found to be 43-125 nm in size, representing another potential mechanism for altering the extracellular environment. a proteomic analysis (lc- ... | 2011 | 21138299 |
| cloning, expression, purification, crystallization and preliminary x-ray diffraction analysis of intracellular growth locus e (igle) protein from francisella tularensis subsp. novicida. | tularaemia is an uncommon but potentially dangerous zoonotic disease caused by the bacterium francisella tularensis. as few as ten bacterial cells are sufficient to cause disease in a healthy human, making this one of the most infectious disease agents known. the virulence of this organism is dependent upon a genetic locus known as the francisella pathogenicity island (fpi), which encodes components of a secretion system that is related to the type vi secretion system. here, the cloning, express ... | 2010 | 21139203 |
| investigation of the ecology of francisella tularensis during an inter-epizootic period. | abstract a 1-year study of the ecological cycle of francisella tularensis was performed in an enzootic area during an inter-epizootic period. the study was based on multiple sampling of all major constituents of the disease cycle. seroprevalence of tularemia in the european brown hare (lepus europaeus) population was 5.1% (10/197) with low antibody titers (1/10 and 1/20), and f. tularensis ssp. holarctica was isolated from four hares. f. tularensis was not detected in the 38 common voles (microt ... | 2010 | 21142970 |
| reliable detection of bacillus anthracis, francisella tularensis and yersinia pestis by using multiplex qpcr including internal controls for nucleic acid extraction and amplification. | several pathogens could seriously affect public health if not recognized timely. to reduce the impact of such highly pathogenic micro-organisms, rapid and accurate diagnostic tools are needed for their detection in various samples, including environmental samples. | 2010 | 21143837 |
| differential requirement for caspase-1 autoproteolysis in pathogen-induced cell death and cytokine processing. | activation of the cysteine protease caspase-1 is a key event in the innate immune response to infections. synthesized as a proprotein, caspase-1 undergoes autoproteolysis within multiprotein complexes called inflammasomes. activated caspase-1 is required for proteolytic processing and for release of the cytokines interleukin-1β and interleukin-18, and it can also cause rapid macrophage cell death. we show that macrophage cell death and cytokine maturation in response to infection with diverse ba ... | 2010 | 21147462 |
| nucleolin, a shuttle protein promoting infection of human monocytes by francisella tularensis. | francisella tularensis is a highly virulent facultative intracellular bacterium, disseminating in vivo mainly within host mononuclear phagocytes. after entry into macrophages, f. tularensis initially resides in a phagosomal compartment, whose maturation is then arrested. bacteria escape rapidly into the cytoplasm, where they replicate freely. we recently demonstrated that nucleolin, an eukaryotic protein able to traffic from the nucleus to the cell surface, acted as a surface receptor for f. tul ... | 2010 | 21152024 |
| crystal structure of the 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase•dihydropteroate synthase bifunctional enzyme from francisella tularensis. | the 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (hppk) and dihydropteroate synthase (dhps) enzymes catalyze sequential metabolic reactions in the folate biosynthetic pathway of bacteria and lower eukaryotes. both enzymes represent validated targets for the development of novel anti-microbial therapies. we report herein that the genes which encode fthppk and ftdhps from the biowarfare agent francisella tularensis are fused into a single polypeptide. the potential of simultaneously targeti ... | 2010 | 21152407 |
| questing ticks in suburban forest are infected by at least six tick-borne pathogens. | abstract the role of ixodes ricinus ticks in the transmission of pathogens of public health importance such as borrelia burgdorferi s.l. is widely recognized and is suspected in several emerging vector-borne pathogens in europe. here, we assess prevalence rates of several endemic and emerging zoonotic pathogens in tick populations in an area of high human population density in france, to contribute to a risk assessment for potential transmission to humans. pathogen prevalence rates were evaluate ... | 2010 | 21158500 |
| preservation of viable francisella tularensis for forensic analysis. | as a preservation solution, (1%) ammonium chloride may be preferred over other conventionally used storage solutions because of its compatibility with analytical techniques such as mass spectrometry. in this study, ammonium chloride performed as well or better than phosphate buffered saline with tween or butterfields/tween for preserving francisella tularensis subsp. novicida. | 2010 | 21167882 |
| il-17 in protective immunity to intracellular pathogens. | the identification of a new t cell subset referred to as t helper 17 (th17) cells and its role in protective immunity against extracellular bacterial infections is well established. in contrast, initial studies suggested that the il-23-il-17 pathway was not required for protection against intracellular pathogens such as mycobacterial infections. however, recent studies demonstrate that th17-il-23 pathway may play a crucial role in protective immunity against other intracellular pathogens by regu ... | 2010 | 21178483 |
| fragmentation-free lc-ms can identify hundreds of proteins. | one of the most common approaches for large-scale protein identification is lc, followed by ms. if more than a few proteins are to be identified, the additional fragmentation of individual peptides has so far been considered as indispensable, and thus, the associated costs, in terms of instrument time and infrastructure, as unavoidable. here, we present evidence to the contrary. using a combination of (i) highly accurate and precise mass measurements, (ii) modern retention time prediction, and ( ... | 2010 | 21182191 |
| iron content differs between francisella tularensis subspecies tularensis and subspecies holarctica strains and correlates to their susceptibility to h(2)o(2)-induced killing. | francisella tularensis, the causative agent of tularemia, is one of the most infectious bacterial pathogens known and is classified as a category a select agent and a facultative intracellular bacterium. why f. tularensis subsp. tularensis causes a more severe form of tularemia than f. tularensis subsp. holarctica does is not known. in this study, we have identified prominent phenotypic differences between the subspecies, since we found that f. tularensis subsp. tularensis strains contained less ... | 2010 | 21189323 |
| chlorine disinfection of francisella tularensis. | to determine the range of free available chlorine (fac) required for disinfection of the live vaccine strain (lvs) and wild-type strains of francisella tularensis. | 2011 | 21189486 |
| glycogen synthase kinase-3 is an early determinant in the differentiation of pathogenic th17 cells. | cd4(+) t cells are critical for host defense but are also major drivers of immune-mediated diseases. the classical view of th1 and th2 subtypes of cd4(+) t cells was recently revised by the identification of the th17 lineage of cd4(+) t cells that produce il-17, which have been found to be critical in the pathogenesis of autoimmune and other diseases. mechanisms controlling the differentiation of th17 cells have been well described, but few feasible targets for therapeutically reducing th17 cell ... | 2010 | 21191064 |
| identification and characterization of novel and potent transcription promoters of francisella tularensis. | two alternative promoter trap libraries, based on the green fluorescence protein (gfp) reporter and on the chloramphenicol acetyltransferase (cat) cassette, were constructed for isolation of potent francisella tularensis promoters. of the 26,000 f. tularensis strain lvs gfp library clones, only 3 exhibited visible fluorescence following uv illumination and all appeared to carry the bacterioferritin promoter (pbfr). out of a total of 2,000 chloramphenicol-resistant lvs clones isolated from the ca ... | 2010 | 21193666 |
| intranasal immunization with an archaeal lipid mucosal vaccine adjuvant and delivery formulation protects against a respiratory pathogen challenge. | archaeal lipid mucosal vaccine adjuvant and delivery (amvad) is a safe mucosal adjuvant that elicits long lasting and memory boostable mucosal and systemic immune responses to model antigens such as ovalbumin. in this study, we evaluated the potential of the amvad system for eliciting protective immunity against mucosal bacterial infections, using a mouse model of intranasal francisella tularensis lvs (lvs) challenge. intranasal immunization of mice with cell free extract of lvs (lvsce) adjuvant ... | 2010 | 21206916 |
| identification of t-cell epitopes in francisella tularensis using an ordered protein array of serological targets. | francisella tularensis is a gram-negative intracellular bacterium that is the causative agent of tularaemia. concerns regarding its use as a bioterrorism agent have led to a renewed interest in the biology of infection, host response and pathogenesis. a robust t-cell response is critical to confer protection against f. tularensis. however, characterization of the cellular immune response has been hindered by the paucity of tools to examine the anti-francisella immune response at the molecular le ... | 2011 | 21214540 |
| phylogeography of francisella tularensis ssp. holarctica in france. | to investigate the phylogeography of french francisella tularensis ssp. holarctica isolates. | 2011 | 21214606 |
| temperature-sensitive bacterial pathogens generated by the substitution of essential genes from cold-loving bacteria: potential use as live vaccines. | temperature-sensitive (ts) viruses have been used for decades as vaccines capable of limited replication in their hosts. although attenuated bacteria, such as the bacille calmette-guérin anti-tuberculosis vaccine, have been used for almost a century, it is only recently that there has been progress in using ts bacterial strains as live vaccines. decades of work on essential bacterial genes and the recent explosion in the number of available bacterial genomic sequences set the groundwork for the ... | 2011 | 21229224 |
| biochemical responses and oxidative stress in francisella tularensis infection: a european brown hare model. | the aim of the present study was to investigate biochemical and oxidative stress responses to experimental f. tularensis infection in european brown hares, an important source of human tularemia infections. | 2011 | 21232117 |
| enediol mimics as inhibitors of the d-arabinose 5-phosphate isomerase (kdsd) from francisella tularensis. | we explored the d-arabinose 5-phosphate isomerase (kdsd, e.c. 5.3.1.13) from francisella tularensis, a highly infectious gram-negative pathogen that has raised concern as a potential bioweapon, as a target for the development of novel chemotherapeutics. f. tularensis kdsd was expressed in escherichia coli from a synthetic gene, purified, and characterized. a group of hydroxamates designed to be mimics of the putative enediol intermediate in the enzyme's catalytic mechanism were prepared and test ... | 2010 | 21236668 |
| identification of a putative chaperone involved in stress resistance and virulence in francisella tularensis. | francisella tularensis is a highly infectious bacterium causing the zoonotic disease tularemia. this facultative intracellular bacterium replicates in vivo mainly inside macrophages and therefore has developed strategies to resist this stressful environment. here, we identified a novel genetic locus that is important for stress resistance and intracellular survival of f. tularensis. in silico and transcriptional analyses suggest that this locus (genes ftl_0200 to ftl_0209 in the live vaccine str ... | 2011 | 21245269 |
| a high-throughput fluorescence polarization assay for inhibitors of gyrase b. | dna gyrase, a type ii topoisomerase that introduces negative supercoils into dna, is a validated antibacterial drug target. the holoenzyme is composed of 2 subunits, gyrase a (gyra) and gyrase b (gyrb), which form a functional a(2)b(2) heterotetramer required for bacterial viability. a novel fluorescence polarization (fp) assay has been developed and optimized to detect inhibitors that bind to the adenosine triphosphate (atp) binding domain of gyrb. guided by the crystal structure of the natural ... | 2011 | 21245469 |
| tularemia in bulgaria 2003-2004. | tularemia is an uncommon but potentially fatal zoonosis. а second outbreak of tularemia in bulgaria, about 40 years after the first, occurred in 1997 in two western regions, near the serbian border. in 2003 tularemia reemerged in the same foci. this retrospective study aimed to evaluate the clinical characteristics and the efficacy of antibiotic therapy in a tularemia resurgence in the slivnitza region in 2003-2004. | 2010 | 21252445 |
| multiple-locus, variable number of tandem repeat analysis (mlva) of the fish-pathogen francisella noatunensis. | since francisella noatunensis was first isolated from cultured atlantic cod in 2004, it has emerged as a global fish pathogen causing disease in both warm and cold water species. outbreaks of francisellosis occur in several important cultured fish species making a correct management of this disease a matter of major importance. currently there are no vaccines or treatments available. a strain typing system for use in studies of f. noatunensis epizootics would be an important tool for disease man ... | 2011 | 21261955 |
| role of neutrophils and nadph phagocyte oxidase in host defense against respiratory infection with virulent francisella tularensis in mice. | francisella tularensis subspecies (subsp.) tularensis is a cdc category a biological warfare agent and inhalation of as few as 15 bacilli can initiate severe disease. relatively little is known about the cellular and molecular mechanisms of host defense against respiratory infection with subsp. tularensis. in this study, we examined the role of neutrophils and nadph phagocyte oxidase in host resistance to pulmonary infection in a mouse intranasal infection model. we found that despite neutrophil ... | 2011 | 21277990 |
| antibodies contribute to effective vaccination against respiratory infection by type a francisella tularensis strains. | pneumonic tularemia is a life-threatening disease caused by inhalation of the highly infectious intracellular bacterium francisella tularensis. the most serious form of the disease associated with the type a strains can be prevented in experimental animals through vaccination with the attenuated live vaccine strain (lvs). the protection is largely cell mediated, but the contribution of antibodies remains controversial. we addressed this issue in a series of passive immunization studies in fische ... | 2011 | 21282410 |
| tularemia. | a 37-year-old woman experienced local symptoms on returning from a camping trip. within three weeks she developed generalized symptoms and was hospitalized. tularemia, and often overlooked cause of bubo formation, is endemic in nevada. the diagnosis should be considered when patients who have visited such an area present with enlarged, painful lymph nodes, skin pustules, ulcers, headache, myalgia, malaise and nausea. cultures tend to be negative, because the causative organism, francisella tular ... | 1982 | 21286087 |
| francisella infections in fish and shellfish. | a series of recent reports have implicated bacteria from the family francisellaceae as the cause of disease in farmed and wild fish and shellfish species such as atlantic cod, gadus morhua l., tilapia, oreochromis spp., atlantic salmon, salmo salar l., three-line grunt, parapristipoma trilineatum (thunberg), ornamental cichlid species, hybrid striped bass morone chrysops x m. saxatilis and, recently, a shellfish species, the giant abalone, haliotisgigantea gmelin. the range of taxa affected will ... | 2011 | 21306585 |
| genotyping of francisella tularensis, the causative agent of tularemia. | francisella tularensis is a facultative, intracellular, zoonotic pathogen and the causative agent of tularemia. historically, f. tularensis has been subdivided into subspecies on the basis of phenotypic traits, including biochemical reactivity and virulence. more recently, a number of genotypic methods, ranging from relatively insensitive methods to full genome sequencing, have been used to investigate genetic diversity within f. tularensis. these analyses indicate that f. tularensis is a pathog ... | 2010 | 21313823 |
| receptor mimicry as novel therapeutic treatment for biothreat agents. | the specter of intentional release of pathogenic microbes and their toxins is a real threat. this article reviews the literature on adhesins of biothreat agents, their interactions with oligosaccharides and the potential for anti-adhesion compounds as an alternative to conventional therapeutics. the minimal binding structure of ricin has been well characterised and offers the best candidate for successful anti-adhesion therapy based on the galβ1-4glcnac structure. the botulinum toxin serotypes a ... | 2010 | 21327124 |
| [epidemiological evaluation of a rapidly-prevented tularemia outbreak in canakkale province, turkey]. | tularemia is a disease caused by francisella tularensis and widely seen at northern hemisphere of the world. in turkey, oropharyngeal infections caused by a less virulent serotype f.tularensis subsp. holarctica are more prevalent. the aim of this study was to present the results of an epidemiological research performed after the detection of tularemia cases from biga county of canakkale province, turkey, in december 2009. following the report of two tularemia suspected cases from two villages (b ... | 2011 | 21341159 |
| [evaluation of the oropharyngeal tularemia cases admitted to our hospital from the provinces of central anatolia]. | tularemia caused by the bacterium francisella tularensis is a zoonotic infection which has re-emerged in turkey in recent years as water-borne endemics. oropharyngeal form is the most frequently reported form of the disease from turkey. the aim of this study was to evaluate the clinical and laboratory findings of oropharyngeal tularemia patients admitted to ear, nose & throat outpatient clinic between january-march 2010. a total of 10 patients (age range: 16-80 years, mean age: 43.9 years; nine ... | 2011 | 21341160 |
| [tularemia seroprevalence in the risky population living in both rural and urban areas of erzurum]. | tularemia which is a zoonotic infection, caused by francisella tularensis, has become a re-emerging disease in turkey. infection is often transmitted to human by handling animal tissues and products, but it is also possible to acquire the disease from contaminated water or food. recently several cases and epidemics of tularemia have been reported in the northwest areas of turkey, particularly in marmara and west black sea regions. erzurum is a city in eastern anatolia region, turkey and animal h ... | 2011 | 21341161 |
| francisella infections in farmed and wild aquatic organisms. | abstract: over the last 10 years or so, infections caused by bacteria belonging to a particular branch of the genus francisella have become increasingly recognised in farmed fish and molluscs worldwide. while the increasing incidence of diagnoses may in part be due to the development and widespread availability of molecular detection techniques, the domestication of new organisms has undoubtedly instigated emergence of clinical disease in some species. francisellosis in fish develops in a simila ... | 2011 | 21385413 |
| an outbreak of disease caused by francisella sp. in nile tilapia oreochromis niloticus at a recirculation fish farm in the uk. | this study details the first diagnosis of francisella sp. in tilapia in the united kingdom. losses of tilapia fry at a recirculation fish farm in england were investigated, giving a presumptive positive diagnosis of infection with francisella sp. by histopathological examination. most fish sampled showed moderate to marked pathology of the major organs, with lesions being present in most tissues. the most obvious host response was granuloma formulation. a subsequent follow-up visit provided furt ... | 2010 | 21387995 |
| seroprevalence of 10 zoonotic infections in 2 canadian cree communities. | we evaluated the seroprevalence of 10 zoonotic agents among the general population (15 years old and over) of eastmain and wemindji, james bay, quebec, in 2007. overall seroprevalence rates were similar between the 2 communities. nearly half the individuals tested (n = 251; 146 women, 105 men) were seropositive (n = 115) for at least one zoonosis. the highest seroprevalence rates were for leptospira sp. (23%), francisella tularensis (17%), and the california serogroup viruses (jc and ssh viruses ... | 2011 | 21398073 |
| eschar and neck lymphadenopathy caused by francisella tularensis after a tick bite: a case report. | | 2011 | 21418587 |
| sensitivity of francisella tularensis to ultrapure water and deoxycholate: implications for bacterial intracellular growth assay in macrophages. | the ability of francisella tularensis to replicate in macrophages is critical for its pathogenesis, therefore intracellular growth assays are important tools for assessing virulence. we show that two lysis solutions commonly used in these assays, deionized water and deoxycholate in pbs, lead to highly inaccurate measurements of intracellular bacterial survival. | 2011 | 21420447 |
| phagocytic receptors dictate phagosomal escape and intracellular proliferation of francisella tularensis. | francisella tularensis, the causative agent of tularemia, survives and proliferates within macrophages of the infected host as part of its pathogenic strategy, through an intracellular life cycle that includes phagosomal escape and extensive proliferation within the macrophage cytosol. various in vitro models of francisella-macrophage interactions have been developed, using either opsonic or nonopsonic phagocytosis, and have generated discrepant results on the timing and extent of francisella ph ... | 2011 | 21422184 |
| features of sepsis caused by pulmonary infection with francisella tularensis type a strain. | the virulence mechanisms of francisella tularensis, the causative agent of severe pneumonia in humans and a cdc category a bioterrorism agent, are not fully defined. as sepsis is the leading cause of mortality associated with respiratory infections, we determined whether, in the absence of any known bacterial toxins, a deregulated host response resulting in sepsis syndrome is associated with lethality of respiratory infection with the virulent human type a strain schus4 of f. tularensis. the c57 ... | 2011 | 21440052 |
| persistence of cell-mediated immunity three decades after vaccination with the live vaccine strain of francisella tularensis. | the efficacy of many vaccines against intracellular bacteria depends on the generation of cell-mediated immunity, but studies to determine the duration of immunity are usually confounded by re-exposure. the causative agent of tularemia, francisella tularensis, is rare in most areas and, therefore, tularemia vaccination is an interesting model for studies of the longevity of vaccine-induced cell-mediated immunity. here, lymphocyte proliferation and cytokine production in response to f. tularensis ... | 2011 | 21442618 |
| measurement of macrophage-mediated killing of intracellular bacteria, including francisella and mycobacteria. | macrophages activated by t cell cytokines are a critical defense mechanism against intracellular bacterial pathogens. this unit presents two general methods for assessing the capacity of mouse macrophages, activated with either soluble cytokines or whole immune t lymphocytes, to control or reduce numbers of intracellular bacteria residing within them. "measurement of killing" is inferred from a reduction in the number of colony-forming units (cfu) of bacteria at the end of a culture period, comp ... | 2011 | 21462167 |
| infection of mice with francisella as an immunological model. | this unit describes the utility of various mouse models of infection for studying pathogenesis and adaptive immune responses to the facultative intracellular bacteria pathogen francisella tularensis. by judicious use of different combinations of mouse and bacterial strains, as well as different routes of infection, murine tularemia models may be used to explore a complete picture of f. tularensis infection and immunity. moreover, studies using francisella, particularly the live vaccine strain (l ... | 2011 | 21462168 |
| tryptophan prototrophy contributes to francisella tularensis evasion of gamma interferon-mediated host defense. | francisella tularensis is able to survive and replicate within host macrophages, a trait that is associated with the high virulence of this bacterium. the trpab genes encode the enzymes required for the final two steps in tryptophan biosynthesis, with trpb being responsible for the conversion of indole to tryptophan. consistent with this function, an f. tularensis subsp. novicida trpb mutant is unable to grow in defined medium in the absence of tryptophan. the trpb mutant is also attenuated for ... | 2011 | 21464086 |
| characterization of monoclonal antibodies to terminal and internal o-antigen epitopes of francisella tularensis lipopolysaccharide. | the lipopolysaccharide (lps) of francisella tularensis (ft), the gram negative bacterium that causes tularemia, has been shown to be a main protective antigen in mice and humans; we have previously demonstrated that murine anti-ft lps igg2a monoclonal antibodies (mabs) can protect mice against otherwise lethal intranasal infection with the ft live vaccine strain (lvs). here we show that four igg2a anti-lps mabs are specific for the o-polysaccharide (o-antigen [oag]) of ft lps. but whereas three ... | 2011 | 21466282 |