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misidentification of burkholderia pseudomallei as burkholderia cepacia by the vitek 2 system.a previously healthy chinese male returned from working in the malaysian jungle with a fever. a blood culture grew gram-negative bacilli that were initially identified as burkholderia cepacia by the vitek 2 system but were subsequently found to be burkholderia pseudomallei by partial sequencing of the 16s rrna gene. the identification of b. pseudomallei using commercially available automated systems is problematic and clinicians in non-endemic areas should be aware of the possibility of melioido ...201222820689
development of a multiplex pcr assay for rapid identification of burkholderia pseudomallei, burkholderia thailandensis, burkholderia mallei and burkholderia cepacia complex.we have developed a multiplex pcr assay for rapid identification and differentiation of cultures for burkholderia pseudomallei, burkholderia thailandensis, burkholderia mallei and burkholderia cepacia complex. the assay is valuable for use in clinical and veterinary laboratories, and in a deployable laboratory during outbreaks.201222705921
the madagascar hissing cockroach as a novel surrogate host for burkholderia pseudomallei, b. mallei and b. thailandensis.burkholderia pseudomallei and burkholderia mallei are gram-negative pathogens responsible for the diseases melioidosis and glanders, respectively. both species cause disease in humans and animals and have been designated as category b select agents by the centers for disease control and prevention (cdc). burkholderia thailandensis is a closely related bacterium that is generally considered avirulent for humans. while it can cause disease in rodents, the b. thailandensis 50% lethal dose (ld50) is ...201222892068
evolution of burkholderia pseudomallei in recurrent melioidosis.burkholderia pseudomallei, the etiologic agent of human melioidosis, is capable of causing severe acute infection with overwhelming septicemia leading to death. a high rate of recurrent disease occurs in adult patients, most often due to recrudescence of the initial infecting strain. pathogen persistence and evolution during such relapsing infections are not well understood. bacterial cells present in the primary inoculum and in late infections may differ greatly, as has been observed in chronic ...201222615773
rapid identification of burkholderia mallei and burkholderia pseudomallei by intact cell matrix-assisted laser desorption/ionisation mass spectrometric typing.burkholderia (b.) pseudomallei and b. mallei are genetically closely related species. b. pseudomallei causes melioidosis in humans and animals, whereas b. mallei is the causative agent of glanders in equines and rarely also in humans. both agents have been classified by the cdc as priority category b biological agents. rapid identification is crucial, because both agents are intrinsically resistant to many antibiotics. matrix-assisted laser desorption/ionisation mass spectrometry (maldi-tof ms) ...201223046611
burkholderia pseudomallei transcriptional adaptation in macrophages.burkholderia pseudomallei is a facultative intracellular pathogen of phagocytic and non-phagocytic cells. how the bacterium interacts with host macrophage cells is still not well understood and is critical to appreciate the strategies used by this bacterium to survive and how intracellular survival leads to disease manifestation.201222823543
mapping the aetiology of non-malarial febrile illness in southeast asia through a systematic review--terra incognita impairing treatment policies.an increasing use of point of care diagnostic tests that exclude malaria, coupled with a declining malaria burden in many endemic countries, is highlighting the lack of ability of many health systems to manage other causes of febrile disease. a lack of knowledge of distribution of these pathogens, and a lack of screening and point-of-care diagnostics to identify them, prevents effective management of these generally treatable contributors to disease burden. while prospective data collection is v ...201222970193
production of interleukin-27 by human neutrophils regulates their function during bacterial infection.septicemia is the most severe form of melioidosis caused by the gram-negative bacterium, burkholderia pseudomallei. here, we show that levels of il-27p28 transcript and protein were both significantly elevated in patients with sepsis, particularly melioidosis and in patients with unfavorable disease outcome. moreover, human monocytes/macrophages and neutrophils were the major source of il-27 during infection. the addition of exogenous il-27 in vitro resulted in significantly increased bacterial ...201222965735
immunogenic recombinant burkholderia pseudomallei mpra serine protease elicits protective immunity in mice.burkholderia pseudomallei is resistant to a diverse group of antimicrobials including third generation cephalosporins whilst quinolones and aminoglycosides have no reliable effect. as therapeutic options are limited, development of more effective forms of immunotherapy is vital to avoid a fatal outcome. in an earlier study, we reported on the b. pseudomallei serine mpra protease, which is relatively stable over a wide ph and temperature range and digests physiological proteins. the present study ...201222919676
structural basis of toxicity and immunity in contact-dependent growth inhibition (cdi) systems.contact-dependent growth inhibition (cdi) systems encode polymorphic toxin/immunity proteins that mediate competition between neighboring bacterial cells. we present crystal structures of cdi toxin/immunity complexes from escherichia coli ec869 and burkholderia pseudomallei 1026b. despite sharing little sequence identity, the toxin domains are structurally similar and have homology to endonucleases. the ec869 toxin is a zn(2+)-dependent dnase capable of completely degrading the genomes of target ...201223236156
particle-size dependent effects in the balb/c murine model of inhalational melioidosis.deposition of burkholderia pseudomallei within either the lungs or nasal passages of the balb/c murine model resulted in different infection kinetics. the infection resulting from the inhalation of b. pseudomallei within a 12 μm particle aerosol was prolonged compared to a 1 μm particle aerosol with a mean time-to-death (mtd) of 174.7 ± 14.9 h and 73.8 ± 11.3 h, respectively. inhalation of b. pseudomallei within 1 μm or 12 μm particle aerosols resulted in a median lethal dose (mld) of 4 and 12 c ...201222919690
a traveller presenting with severe melioidosis complicated by a pericardial effusion: a case report.burkholderia pseudomallei, the etiologic agent of melioidosis, is endemic to tropic regions, mainly in southeast asia and northern australia. melioidosis occurs only sporadically in travellers returning from disease-endemic areas. severe clinical disease is seen mostly in patients with alteration of immune status. in particular, pericardial effusion occurs in 1-3% of patients with melioidosis, confined to endemic regions. to our best knowledge, this is the first reported case of melioidosis in a ...201223035948
the effect of environmental conditions on biofilm formation of burkholderia pseudomallei clinical isolates.burkholderia pseudomallei, a gram-negative saprophytic bacterium, is the causative agent of the potentially fatal melioidosis disease in humans. in this study, environmental parameters including temperature, nutrient content, ph and the presence of glucose were shown to play a role in in vitro biofilm formation by 28 b. pseudomallei clinical isolates, including four isolates with large colony variants (lcvs) and small colony variants (scvs) morphotypes. enhanced biofilm formation was observed wh ...201222970167
humoral immune responses in a human case of glanders.within 2 months of acquiring glanders, a patient developed 8-, 16-, and 4-fold increases, respectively, in specific iga, igg, and igm serological titers against burkholderia mallei. within 14 months of infection, the titers decreased to the baseline. serum from this patient was also highly reactive against burkholderia pseudomallei whole cells. burkholderia mallei whole cells did not react with sera from patients with other diseases. therefore, an assay using a b. mallei cellular diagnostic anti ...201222398248
the genetic and molecular basis of o-antigenic diversity in burkholderia pseudomallei lipopolysaccharide.lipopolysaccharide (lps) is one of the most important virulence and antigenic components of burkholderia pseudomallei, the causative agent of melioidosis. lps diversity in b. pseudomallei has been described as typical, atypical or rough, based upon banding patterns on sds-page. here, we studied the genetic and molecular basis of these phenotypic differences. bioinformatics was used to determine the diversity of genes known or predicted to be involved in biosynthesis of the o-antigenic moiety of ...201222235357
natural history of inhalation melioidosis in rhesus macaques (macaca mulatta) and african green monkeys (chlorocebus aethiops).burkholderia pseudomallei, the causative agent of melioidosis, is recognized as a serious health threat due to its involvement in septic and pulmonary infections in areas of endemicity and is recognized by the centers for disease control and prevention as a category b biothreat agent. an animal model is desirable to evaluate the pathogenesis of melioidosis and medical countermeasures. a model system that represents human melioidosis infections is essential in this process. a group of 10 rhesus m ...201222778104
when it comes to drug discovery not all gram-negative bacterial biodefence pathogens are created equal: burkholderia pseudomallei is different. 201222385701
the potential of taqman array cards for detection of multiple biological agents by real-time pcr.the taqman array card architecture, normally used for gene expression studies, was evaluated for its potential to detect multiple bacterial agents by real-time pcr. ten pcr assays targeting five biological agents (bacillus anthracis, burkholderia mallei, burkholderia pseudomallei, francisella tularensis, and yersinia pestis) were incorporated onto array cards. a comparison of pcr performance of each pcr in array card and singleplex format was conducted using dna extracted from pure bacterial cul ...201222540014
prophylactic application of cpg oligonucleotides augments the early host response and confers protection in acute melioidosis.prophylactic administration of cpg oligodeoxynucleotides (cpg odns) is known to confer protection against lethal sepsis caused by burkholderia pseudomallei in the mouse model. the mechanisms whereby cpg regulates the innate immune response to provide protection against b. pseudomallei, however, are poorly characterized. in the present study, we demonstrate that intranasal treatment of mice with class c cpg, results in recruitment of inflammatory monocytes and neutrophils to the lung at 48 h post ...201222448290
application of polymerase chain reaction to detect burkholderia pseudomallei and brucella species in buffy coat from patients with febrile illness among rural and peri-urban population.melioidosis and brucellosis are important endemic infections among people in india, especially in rural settings. conventional detection techniques have several limitations. only a few studies exist on the prevalence of melioidosis and brucellosis in rural area especially in india.201222529625
computational discovery and rt-pcr validation of novel burkholderia conserved and burkholderia pseudomallei unique srnas.the srnas of bacterial pathogens are known to be involved in various cellular roles including environmental adaptation as well as regulation of virulence and pathogenicity. it is expected that srnas may also have similar functions for burkholderia pseudomallei, a soil bacterium that can adapt to diverse environmental conditions, which causes the disease melioidosis and is also able to infect a wide variety of hosts.201223282220
characterisation of the burkholderia pseudomallei k96243 cps i coding region.burkholderia pseudomallei is the causative agent of melioidosis, a disease endemic to regions of southeast asia and northern australia. both humans and a range of other animal species are susceptible to melioidosis and the production of a group 3 polysaccharide capsule in b. pseudomallei is essential for virulence. this b. pseudomallei capsular polysaccharide (cps) i comprises unbranched manno-heptopyranose residues and is encoded by a 34.5 kb locus on chromosome 1. despite the importance of thi ...201222252864
role of rela and spot in burkholderia pseudomallei virulence and immunity.burkholderia pseudomallei is a gram-negative soil bacterium and the causative agent of melioidosis, a disease of humans and animals. it is also listed as a category b bioterrorism threat agent by the u.s. centers for disease control and prevention, and there is currently no melioidosis vaccine available. small modified nucleotides such as the hyperphosphorylated guanosine molecules ppgpp and pppgpp play an important role as signaling molecules in prokaryotes. they mediate a global stress respons ...201222778096
a non-invasive intratracheal inoculation method for the study of pulmonary melioidosis.pulmonary melioidosis, a disease manifestation caused by the bacterium burkholderia pseudomallei, has been studied using aerosols or intranasal (in) inoculation in small animal models. both have inherent disadvantages which may not accurately model primary pulmonary melioidosis in humans. intratracheal inoculation (it) by direct visualization of the tracheal opening offers an alternative technique for infection that overcomes the disadvantages of aerosol and in challenge. in this study, we descr ...201223267442
antimicrobial and antibiofilm activity of ll-37 and its truncated variants against burkholderia pseudomallei.the gram-negative bacterium burkholderia pseudomallei is the aetiological agent of melioidosis, which is an endemic disease in tropical areas of southeast asia and northern australia. burkholderia pseudomallei has intrinsic resistance to a number of commonly used antibiotics and has also been reported to develop a biofilm. resistance to killing by antimicrobial agents is one of the hallmarks of bacteria grown in biofilm. the aim of this study was to determine the antimicrobial activity and mecha ...201222005071
Proteomic analysis of colony morphology variants of Burkholderia pseudomallei defines a role for the arginine deiminase system in bacterial survival.Colony morphology variation of Burkholderia pseudomallei is a notable feature of a proportion of primary clinical cultures from patients with melioidosis. Here, we examined the hypothesis that colony morphology switching results in phenotypic changes associated with enhanced survival under adverse conditions. We generated isogenic colony morphology types II and III from B. pseudomallei strain 153 type I, and compared their protein expression profiles using 2D gel electrophoresis. Numerous protei ...201222062159
cationic liposomes extend the immunostimulatory effect of cpg oligodeoxynucleotide against burkholderia pseudomallei infection in balb/c mice.melioidosis is a severe disease caused by the gram-negative bacterium burkholderia pseudomallei. previously we showed that pretreatment of mice with cpg oligodeoxynucleotide (cpg odn) 2 to 10 days prior to b. pseudomallei challenge conferred as high as 90% protection, but this window of protection was rather short. in the present study, we therefore aimed to prolong this protective window and to gain further insight into the mechanisms underlying the protection induced by cpg odn against b. pseu ...201222441390
cloning, purification, crystallization and preliminary x-ray analysis of the burkholderia pseudomallei l1 ribosomal protein.the gene encoding the l1 ribosomal protein from burkholderia pseudomallei strain d286 has been cloned into the petblue-1 vector system, overexpressed in escherichia coli and purified. crystals of the native protein were grown by the hanging-drop vapour-diffusion technique using peg 3350 as a precipitant and diffracted to beyond 1.65 å resolution. the crystals belonged to space group p2(1)2(1)2, with unit-cell parameters a = 53.6, b = 127.1, c = 31.8 å and with a single molecule in the asymmetric ...201222442241
expression and function of transforming growth factor β in melioidosis.melioidosis, caused by the gram-negative bacterium burkholderia pseudomallei, is an important cause of community-acquired sepsis in southeast asia and northern australia. an important controller of the immune system is the pleiotropic cytokine transforming growth factor β (tgf-β), of which smad2 and smad3 are the major signal transducers. in this study, we aimed to characterize tgf-β expression and function in experimental melioidosis. tgf-β expression was determined in 33 patients with culture- ...201222331429
comparison of two suspension arrays for simultaneous detection of five biothreat bacterial in powder samples.we have developed novel bio-plex assays for simultaneous detection of bacillus anthracis, yersinia pestis, brucella spp., francisella tularensis, and burkholderia pseudomallei. universal primers were used to amplify highly conserved region located within the 16s rrna amplicon, followed by hybridized to pathogen-specific probes for identification of these five organisms. the other assay is based on multiplex pcr to simultaneously amplify five species-specific pathogen identification-targeted regi ...201222690123
burkholderia mallei and burkholderia pseudomallei stimulate differential inflammatory responses from human alveolar type ii cells (atii) and macrophages.alveolar type ii pneumocytes (atii) and alveolar macrophages (am) play a crucial role in the lung's innate immune response. burkholderia pseudomallei (bp) and burkholderia mallei (bm) are facultative gram-negative bacilli that cause melioidosis and glanders, respectively. the inhalation of these pathogens can cause lethal disease and death in humans. we sought to compare the pathogenesis of and host responses to bp and bm through contact with human primary atii cells and monocytes-derived macrop ...201223293773
bacteraemias in tropical australia: changing trends over a 10-year period.bacteraemia is an important cause of morbidity and mortality worldwide. this is the largest reported study of bacteraemias in australia. the presence of organisms endemic to the tropical region and the changing trends described have significant implications for empirical antibiotic therapy. this retrospective study examined 8976 blood cultures from townsville hospital, a regional australian hospital located in the tropics over a 10-year period. the rate of bacteraemic episodes during the study p ...201223276769
growth inhibition of pathogenic bacteria by sulfonylurea herbicides.emerging resistance to current antibiotics raises the need for new microbial drug targets. we show that targeting branched-chain amino acid (bcaa) biosynthesis using sulfonylurea herbicides, which inhibit the bcaa biosynthetic enzyme acetohydroxyacid synthase (ahas), can exert bacteriostatic effects on several pathogenic bacteria, including burkholderia pseudomallei, pseudomonas aeruginosa, and acinetobacter baumannii. our results suggest that targeting biosynthetic enzymes like ahas, which are ...201223263008
melioidosis of chest wall masquerading as a tubercular cold abscess.melioidosis caused by burkholderia pseudomallei, an important human pathogen in the tropical regions causes protean and multisystem clinical manifestations. a 50-year-old man on treatment for pulmonary tuberculosis developed a chest wall abscess. with a suspicion of tuberculous cold abscess, pus culture was done and it revealed burkholderia pseudomallei. he was treated with 10 days of ceftazidime and incision and drainage was done. wound healed well and he has now completed three months of oral ...201223741590
burkholderia pseudomallei infection in a healthy adult from a rural area of south india.melioidosis is an emerging disease producing protean manifestations, and is more common in alcoholics and diabetics. the disease can be a trivial localized lesion or a fatal septicemia. early diagnosis and appropriate antimicrobial treatment greatly reduces the mortality rate. we report a case of localized form of the disease in an elderly male with no known predisposing medical disease who responded well to oral amoxycillin-clavulanic acid and cotrimoxazole treatment.201223455813
capsule influences the deposition of critical complement c3 levels required for the killing of burkholderia pseudomallei via nadph-oxidase induction by human neutrophils.burkholderia pseudomallei is the causative agent of melioidosis and is a major mediator of sepsis in its endemic areas. because of the low ld(50) via aerosols and resistance to multiple antibiotics, it is considered a tier 1 select agent by the cdc and aphis. b. pseudomallei is an encapsulated bacterium that can infect, multiply, and persist within a variety of host cell types. in vivo studies suggest that macrophages and neutrophils are important for controlling b. pseudomallei infections, howe ...201223251706
burkholderia pseudomallei known siderophores and hemin uptake are dispensable for lethal murine melioidosis.burkholderia pseudomallei is a mostly saprophytic bacterium, but can infect humans where it causes the difficult-to-manage disease melioidosis. even with proper diagnosis and prompt therapeutic interventions mortality rates still range from >20% in northern australia to over 40% in thailand. surprisingly little is yet known about how b. pseudomallei infects, invades and survives within its hosts, and virtually nothing is known about the contribution of critical nutrients such as iron to the bact ...201222745846
identification and evaluation of twin-arginine translocase inhibitors.the twin-arginine translocase (tat) in some bacterial pathogens, including pseudomonas aeruginosa, burkholderia pseudomallei, and mycobacterium tuberculosis, contributes to pathogenesis by translocating extracellular virulence determinants across the inner membrane into the periplasm, thereby allowing access to the xcp (type ii) secretory system for further export in gram-negative organisms, or directly to the outside surface of the cell, as in m. tuberculosis. tat-mediated secretion appreciably ...201223006747
burkholderia thailandensis is virulent in drosophila melanogaster.melioidosis is a serious infectious disease endemic to southeast asia and northern australia. this disease is caused by the gram-negative bacterium burkholderia pseudomallei; burkholderia thailandensis is a closely-related organism known to be avirulent in humans. b. thailandensis has not previously been used to infect drosophila melanogaster. we examined the effect of b. thailandensis infection on fly survival, on antimicrobial peptide expression, and on phagocytic cells. in the fruit fly, whic ...201223209596
the toxin/immunity network of burkholderia pseudomallei contact-dependent growth inhibition (cdi) systems.burkholderia pseudomallei is a category b pathogen and the causative agent of melioidosis--a serious infectious disease that is typically acquired directly from environmental reservoirs. nearly all b. pseudomallei strains sequenced to date (> 85 isolates) contain gene clusters that are related to the contact-dependent growth inhibition (cdi) systems of γ-proteobacteria. cdi systems from escherichia coli and dickeya dadantii play significant roles in bacterial competition, suggesting these system ...201222435733
novel gain of function approaches for vaccine candidate identification in burkholderia pseudomallei.the gram-negative bacterium burkholderia pseudomallei is a serious environmental pathogen and the causative agent of the often fatal melioidosis. disease occurs following exposure to contaminated water or soil, usually through cuts in the skin or via inhalation. however, the underlying mechanisms of pathogenicity remain poorly understood. b. pseudomallei is endemic to south east asia and northern australia where infections are associated with antibiotic resistance and high mortality rates. categ ...201223316481
mechanisms of antibiotic resistance in burkholderia pseudomallei: implications for treatment of melioidosis.burkholderia pseudomallei is the etiologic agent of melioidosis. this multifaceted disease is difficult to treat, resulting in high morbidity and mortality. treatment of b. pseudomallei infections is lengthy and necessitates an intensive phase (parenteral ceftazidime, amoxicillin-clavulanic acid or meropenem) and an eradication phase (oral trimethoprim-sulfamethoxazole). the main resistance mechanisms affecting these antibiotics include enzymatic inactivation, target deletion and efflux from the ...201223231488
mexxy multidrug efflux system of pseudomonas aeruginosa.anti-pseudomonas aminoglycosides, such as amikacin and tobramycin, are used in the treatment of pseudomonas aeruginosa infections. however, their use is linked to the development of resistance. during the last decade, the mexxy multidrug efflux system has been comprehensively studied, and numerous reports of laboratory and clinical isolates have been published. this system has been increasingly recognized as one of the primary determinants of aminoglycoside resistance in p. aeruginosa. in p. aer ...201223233851
bacterial gene loss as a mechanism for gain of antimicrobial resistance.acquisition of exogenous dna by pathogenic bacteria represents the basis for much of the acquired antimicrobial resistance in pathogenic bacteria. a more extreme mechanism to avoid the effect of an antibiotic is to delete the drug target, although this would be predicted to be rare since drug targets are often essential genes. here, we review and discuss the description of a novel mechanism of resistance to the cephalosporin drug ceftazidime caused by loss of a penicillin-binding protein (pbp) i ...201223022568
the use of nanoscale visible light-responsive photocatalyst tio2-pt for the elimination of soil-borne pathogens.exposure to the soil-borne pathogens burkholderia pseudomallei and burkholderia cenocepacia can lead to severe infections and even mortality. these pathogens exhibit a high resistance to antibiotic treatments. in addition, no licensed vaccine is currently available. a nanoscale platinum-containing titania photocatalyst (tio(2)-pt) has been shown to have a superior visible light-responsive photocatalytic ability to degrade chemical contaminants like nitrogen oxides. the antibacterial activity of ...201222384003
nasal acai polysaccharides potentiate innate immunity to protect against pulmonary francisella tularensis and burkholderia pseudomallei infections.pulmonary francisella tularensis and burkholderia pseudomallei infections are highly lethal in untreated patients, and current antibiotic regimens are not always effective. activating the innate immune system provides an alternative means of treating infection and can also complement antibiotic therapies. several natural agonists were screened for their ability to enhance host resistance to infection, and polysaccharides derived from the acai berry (acai ps) were found to have potent abilities a ...201222438809
towards a rapid molecular diagnostic for melioidosis: comparison of dna extraction methods from clinical specimens.optimising dna extraction from clinical samples for burkholderia pseudomallei type iii secretion system real-time pcr in suspected melioidosis patients confirmed that urine and sputum are useful diagnostic samples. direct testing on blood remains problematic; testing dna extracted from plasma was superior to dna from whole blood or buffy coat.201222108495
typhoon-related leptospirosis and melioidosis, taiwan, 2009.to the editor: global climatic changes have resulted in more natural disasters worldwide. these natural disasters can then cause outbreaks of emerging infectious diseases, including leptospirosis and melioidosis (1-7). in 2009, the moderate-strength typhoon morakot, with a maximum cumulative rainfall amount up to 3,059.5 mm, damaged taiwan. after this natural disaster, unusual epidemics of leptospirosis and melioidosis occurred. the main objective of this study was to clarify whether these epide ...201121762606
burkholderia multivorans acts as an antagonist against the growth of burkholderia pseudomallei in soil.burkholderia multivorans nki379 has an antagonistic effect against the growth of b. pseudomallei, which we have demonstrated here using agar diffusion tests and a transwell system. bacterial representatives were isolated from agricultural crop soil and mixed to construct a partial bacterial community structure that based on the results of reproducible patterns following pcr-dgge (denaturing gradient gel electrophoresis) analysis from total soil chromosomes. the antagonistic effect of b. multivor ...201121752084
molecular investigations of pena-mediated ß-lactam resistance in burkholderia pseudomallei.burkholderia pseudomallei is the etiological agent of melioidosis. because of the bacterium's intrinsic resistance and propensity to establish latent infections, melioidosis therapy is complicated and prolonged. newer generation ß-lactams, specifically ceftazidime, are used for acute phase therapy, but resistance to this cephalosporin has been observed. the chromosomally encoded pena gene encodes a putative twin arginine translocase (tat)-secreted ß-lactamase, and pena mutations have been implic ...201121747814
evidence of burkholderia pseudomallei-specific immunity in patient sera persistently nonreactive by the indirect hemagglutination assay.the indirect hemagglutination assay (iha) is the most frequently used serological test to confirm exposure to burkholderia pseudomallei. patients with culture-confirmed disease often have a nonreactive iha at presentation and occasionally fail to seroconvert on serial testing. we investigated whether using antigens derived from the cultured isolates of persistently iha-nonreactive patient sera improved the sensitivity of the iha. in addition, we assessed the antigen-specific lymphocyte response ...201121677111
plasminogen activator inhibitor type i contributes to protective immunity during experimental gram-negative sepsis (melioidosis).melioidosis is a frequent cause of sepsis in southeast asia caused by the gram-negative bacterium burkholderia pseudomallei. patients with melioidosis have elevated circulating levels of plasminogen activator inhibitor type 1 (pai-1), an important regulator of inflammation and fibrinolysis.201121848642
altered macrophage function is associated with severe burkholderia pseudomallei infection in a murine model of type 2 diabetes.this study used a murine model of type 2 diabetes (bks.cg-dock7(m) +/+lepr(db)/j mice) to investigate the inflammatory and cellular mechanisms predisposing to burkholderia pseudomallei infection and co-morbid diabetes. homozygous db/db (diabetic) mice developed extreme obesity, dyslipidaemia and glucose intolerance leading to hyperglycaemia and overt type 2 diabetes. compared to their heterozygous db/+ (non-diabetic) littermates, diabetic mice rapidly succumbed to subcutaneous b. pseudomallei in ...201121835260
burkholderia pseudomallei: an uncommon cause of bacteraemic pneumonia in a diabetic.a 55-year-old woman presented with fever, breathlessness and shock. she was diagnosed to have diabetes mellitus (type 2) after admission. blood culture grew burkholderia pseudomallei. the patient responded to intravenous ceftozidime for two weeks and a prolonged course of six months with cotrimoxazole and doxycycline.201121838203
changes in the repertoire of natural antibodies caused by immunization with bacterial antigens.the repertoire of natural anti-glycan antibodies in naïve chickens and in chickens immunized with bacteria burkholderia mallei, burkholderia pseudomallei, and francisella tularensis as well as with peptides from an outer membrane protein of b. pseudomallei was studied. a relatively restricted pattern of natural antibodies (first of all igy against bacterial cell wall peptidoglycan fragments, l-rha, and core n-acetyllactosamine) shrank and, moreover, the level of detectable antibodies decreased a ...201121999548
molecular characterization of clinical burkholderia pseudomallei isolates from india.multilocus sequence typing of seven isolates of burkholderia pseudomallei from india showed considerable diversity, with six different sequence types. possible dissemination of melioidosis by historical trading routes is supported by links to strains from southeast asia, china, and africa and the presence of the burkholderia mallei allele of the bima gene.201121734136
dissection of the burkholderia intracellular life cycle using a photothermal nanoblade.burkholderia pseudomallei and burkholderia thailandensis are related pathogens that invade a variety of cell types, replicate in the cytoplasm, and spread to nearby cells. we have investigated temporal and spatial requirements for virulence determinants in the intracellular life cycle, using genetic dissection and photothermal nanoblade delivery, which allows efficient placement of bacterium-sized cargo into the cytoplasm of mammalian cells. the conserved bsa type iii secretion system (t3ss(bsa) ...201121730143
alanine racemase mutants of burkholderia pseudomallei and burkholderia mallei and use of alanine racemase as a non-antibiotic-based selectable marker.burkholderia pseudomallei and burkholderia mallei are category b select agents and must be studied under bsl3 containment in the united states. they are typically resistant to multiple antibiotics, and the antibiotics used to treat b. pseudomallei or b. mallei infections may not be used as selective agents with the corresponding burkholderia species. here, we investigated alanine racemase deficient mutants of b. pseudomallei and b. mallei for development of non-antibiotic-based genetic selection ...201121720554
An ensemble of structures of Burkholderia pseudomallei 2,3-bisphosphoglycerate-dependent phosphoglycerate mutase.Burkholderia pseudomallei is a soil-dwelling bacterium endemic to Southeast Asia and Northern Australia. Burkholderia is responsible for melioidosis, a serious infection of the skin. The enzyme 2,3-bisphosphoglycerate-dependent phosphoglycerate mutase (PGAM) catalyzes the interconversion of 3-phosphoglycerate and 2-phosphoglycerate, a key step in the glycolytic pathway. As such it is an extensively studied enzyme and X-ray crystal structures of PGAM enzymes from multiple species have been elucid ...201121904048
acute melioid community-acquired pneumonia.to better understand the characteristics of patients with acute melioid community-acquired pneumonia (cap) on emergency department (ed) arrival, and the risk factors in patients with acute melioid cap that differ from those in patients with severe cap of causes other than melioidosis.201121696989
bopc is a type iii secreted effector protein of burkholderia pseudomallei.burkholderia pseudomallei, the causative agent of melioidosis, exploits the bsa type iii secretion system (t3ss) to deliver effector proteins into host cells. these effectors manipulate host cell functions; thus, contributing to the ability of the bacteria to evade the immune response and cause disease. only two bsa-secreted effectors have been conclusively identified to date. here, we report the identification of the third b. pseudomallei type iii secreted effector protein, designated bopc. bop ...201122092682
Probing conformational states of glutaryl-CoA dehydrogenase by fragment screening.Glutaric acidemia type 1 is an inherited metabolic disorder which can cause macrocephaly, muscular rigidity, spastic paralysis and other progressive movement disorders in humans. The defects in glutaryl-CoA dehydrogenase (GCDH) associated with this disease are thought to increase holoenzyme instability and reduce cofactor binding. Here, the first structural analysis of a GCDH enzyme in the absence of the cofactor flavin adenine dinucleotide (FAD) is reported. The apo structure of GCDH from Burkh ...201121904051
a naturally derived outer-membrane vesicle vaccine protects against lethal pulmonary burkholderia pseudomallei infection.burkholderia pseudomallei, and other members of the burkholderia, are among the most antibiotic-resistant bacterial species encountered in human infection. mortality rates associated with severe b. pseudomallei infection approach 50% despite therapeutic treatment. a protective vaccine against b. pseudomallei would dramatically reduce morbidity and mortality in endemic areas and provide a safeguard for the u.s. and other countries against biological attack with this organism. in this study, we in ...201121871517
A Burkholderia pseudomallei toxin inhibits helicase activity of translation factor eIF4A.The structure of BPSL1549, a protein of unknown function from Burkholderia pseudomallei, reveals a similarity to Escherichia coli cytotoxic necrotizing factor 1. We found that BPSL1549 acted as a potent cytotoxin against eukaryotic cells and was lethal when administered to mice. Expression levels of bpsl1549 correlate with conditions expected to promote or suppress pathogenicity. BPSL1549 promotes deamidation of glutamine-339 of the translation initiation factor eIF4A, abolishing its helicase ac ...201122076380
structure of 3-ketoacyl-(acyl-carrier-protein) reductase from rickettsia prowazekii at 2.25 å resolution.rickettsia prowazekii, a parasitic gram-negative bacterium, is in the second-highest biodefense category of pathogens of the national institute of allergy and infectious diseases, but only a handful of structures have been deposited in the pdb for this bacterium; to date, all of these have been solved by the ssgcid. owing to its small genome (about 800 protein-coding genes), it relies on the host for many basic biosynthetic processes, hindering the identification of potential antipathogenic drug ...201121904060
bioluminescent diagnostic imaging to characterize altered respiratory tract colonization by the burkholderia pseudomallei capsule mutant.pneumonia is a common manifestation of the potentially fatal disease melioidosis, caused by the select agent bacteria burkholderia pseudomallei. in this study we describe a new model system to investigate pulmonary melioidosis in vivo using bioluminescent-engineered bacteria in a murine respiratory disease model. studies were performed to validate that the stable, light producing b. pseudomallei strain jw280 constitutively produced light in biologically relevant host-pathogen interactions. hairl ...201121720539
knockout and pullout recombineering for naturally transformable burkholderia thailandensis and burkholderia pseudomallei.phage ++-red proteins are powerful tools for pulling and knocking out chromosomal fragments but have been limited to the +¦-proteobacteria. procedures are described here to easily knock out (ko) and pull out (po) chromosomal dna fragments from naturally transformable burkholderia thailandensis and burkholderia pseudomallei. this system takes advantage of published compliant counterselectable and selectable markers (sacb, phes, gat and the arabinose-utilization operon) and ++-red mutant proteins. ...201121738123
pulmonary melioidosis in cambodia: a prospective study.abstract: background: melioidosis is a disease caused by burkholderia pseudomallei and considered endemic in south-east asia but remains poorly documented in cambodia. we report the first series of hospitalized pulmonary melioidosis cases identified in cambodia describing clinical characteristics and outcomes. methods: we characterized cases of acute lower respiratory infections (alri) that were identified through surveillance in two provincial hospitals. severity was defined by systolic blood p ...201121569563
in vitro activity of bal30072 against burkholderia pseudomallei.burkholderia pseudomallei is an intrinsically antibiotic-resistant category b priority pathogen and the aetiological agent of melioidosis. treatment of b. pseudomallei infection is biphasic and lengthy in order to combat the acute and chronic phases of the disease. acute-phase treatment preferably involves an intravenous cephalosporin (ceftazidime) or a carbapenem (imipenem or meropenem). in this study, the anti-b. pseudomallei efficacy of a new monosulfactam, bal30072, was tested against labora ...201121596528
[melioidosis: a poorly known tropical disease].a 35 year-old man was admitted to the hospital for fever upon returning from the caribbean area. he died 48 hours later, after developing pulmonary lesions that were complicated by multi-organ failure, despite rapid diagnosis of melioidosis by mass spectrometry on blood cultures. melioidosis is a rare bacterial disease in the traveller that is caused by burkholderia pseudomallei. although the clinical presentation is variable, pneumonia is the most frequent finding. diagnosis may be considered i ...201121692313
development and application of a cellular, gain-of-signal, bioluminescent reporter screen for inhibitors of type ii secretion in pseudomonas aeruginosa and burkholderia pseudomallei.the type ii secretion (t2s) system in gram-negative bacteria comprises the sec and tat pathways for translocating proteins into the periplasm and an outer membrane secretin for transporting proteins into the extracellular space. to discover sec/tat/t2s pathway inhibitors as potential new therapeutics, the authors used a pseudomonas aeruginosa bioluminescent reporter strain responsive to seca depletion and inhibition to screen compound libraries and characterize the hits. the reporter strain plac ...201121602485
burkholderia pseudomallei infection in a child with cystic fibrosis: acquisition in the western hemisphere.melioidosis, an infection caused by the bacterium burkholderia pseudomallei, is endemic to southeast asia and northern australia but is only very rarely seen in patients in the united states. we report pulmonary b pseudomallei infection in a young girl with cystic fibrosis (cf) who had never traveled to asia or australia. biochemical and epidemiologic investigation determined aruba as the likely site of disease acquisition. this report highlights the ability of patients with cf to acquire this o ...201121729895
rapid identification of burkholderia pseudomallei and burkholderia mallei by fluorescence in situ hybridization (fish) from culture and paraffin-embedded tissue samples.we evaluated newly developed probes for rapid identification of burkholderia (b.) pseudomallei and b. mallei and differentiation from b. thailandensis by fluorescence in situ hybridization (fish). fish correctly identified 100% of the tested b. pseudomallei (11), b. mallei (11), and b. thailandensis (1) strains, excluded 100% of all tested negative controls (61), and allowed demonstration of b. pseudomallei infection in a paraffin-embedded spleen tissue sample of an experimentally infected mouse ...201121658996
superoxide dismutase c is required for intracellular survival and virulence of burkholderia pseudomallei.burkholderia pseudomallei is an intracellular pathogen and the causative agent of melioidosis, a life-threatening disease of humans. within host cells, superoxide is an important mediator of pathogen killing. in this study, we have identified the b. pseudomallei k96243 sodc gene, shown that it has superoxide dismutase activity, and constructed an allelic deletion mutant of this gene. compared with the wild-type, the mutant was more sensitive to killing by extracellular superoxide, but not to sup ...201121659326
regulation of type vi secretion system during burkholderia pseudomallei infection.type iii and type vi secretion systems (t3sss and t6sss, respectively) are critical virulence determinants in several gram-negative pathogens. in burkholderia pseudomallei, the t3ss-3 and t6ss-1 clusters have been implicated in bacterial virulence in mammalian hosts. we recently discovered a regulatory cascade that coordinately controls the expression of t3ss-3 and t6ss-1. bsan is a central regulator located within t3ss-3 for the expression of t3ss-3 effectors and regulators for t6ss-1 such as v ...201121670170
autotransporters and their role in the virulence of burkholderia pseudomallei and burkholderia mallei.burkholderia pseudomallei and burkholderia mallei are closely related gram-negative bacteria responsible for the infectious diseases melioidosis and glanders, respectively. autotransporters (ats) comprise a large and diverse family of secreted and outer membrane proteins that includes virulence-associated invasins, adhesins, proteases, and actin-nucleating factors. the b. pseudomallei k96243 genome contains 11 predicted ats, eight of which share homologs in the b. mallei atcc 23344 genome. this ...201121811486
highly sensitive direct detection and quantification of burkholderia pseudomallei in environmental soil samples using real-time pcr.the soil bacterium and potential biothreat agent burkholderia pseudomallei causes the infectious disease melioidosis, which is naturally acquired through environmental contact with the bacterium. environmental detection of b. pseudomallei represents the basis for the development of a geographical risk map to humans and livestock. the aim of the present study was to develop a highly sensitive culture-independent dna-based method that allows direct quantification of b. pseudomallei from soil. we e ...201121803915
endovascular therapy for infected aortic aneurysms.objective: to determine the outcome of endovascular therapy for an infected aortic aneurysm in patients with or without aorto-aerodigestive/aortocaval fistulas. methods: from september 2005 to may 2010, 21 patients, 17 abdominal and four thoracic infected aortic aneurysms were treated with an endovascular stent graft at songklanagarind hospital, thailand. five patients presented with fistula complications, 1 aortoesophageal, 1 aortobronchial, 1 aortocaval, and 2 aortoenteric fistulas. lifelong a ...201121802238
Two Norwegian patients with melioidosis presenting with bacteraemia and splenic and prostatic abscesses.Infections caused by Burkholderia pseudomallei are rare in nonendemic areas, such as Scandinavia. We report the first two cases of melioidosis in Norway presenting with bacteraemia and splenic and prostatic abscesses, respectively.201122017720
Structural basis of the substrate specificity of bifunctional isocitrate dehydrogenase kinase/phosphatase.Isocitrate dehydrogenase kinase/phosphatase (AceK) regulates entry into the glyoxylate bypass by reversibly phosphorylating isocitrate dehydrogenase (ICDH). On the basis of the recently determined structure of the AceK-ICDH complex from Escherichia coli, we have classified the structures of homodimeric NADP(+)-ICDHs to rationalize and predict which organisms likely contain substrates for AceK. One example is Burkholderia pseudomallei (Bp). Here we report a crystal structure of Bp-ICDH that exhib ...201121870819
A Burkholderia pseudomallei macrophage infectivity potentiator-like protein has rapamycin-inhibitable peptidylprolyl isomerase activity and pleiotropic effects on virulence.Macrophage infectivity potentiators (Mips) are a group of virulence factors encoded by pathogenic bacteria such as Legionella, Chlamydia, and Neisseria species. Mips are part of the FK506-binding protein (FKBP) family, whose members typically exhibit peptidylprolyl cis-trans isomerase (PPIase) activity which is inhibitable by the immunosuppressants FK506 and rapamycin. Here we describe the identification and characterization of BPSS1823, a Mip-like protein in the intracellular pathogen Burkholde ...201121859853
melioidosis of the extremities in brunei darussalam.introduction: melioidosis caused by burkholderia pseudomallei is an infectious disease endemic to southeast asia and northern australia. it has a broad spectrum of clinical manifestations and high mortality, and can mimic other infectious diseases. the aim of this study was to review cases of melioidosis of the extremities in brunei darussalam. methods: culture-positive cases for burkholderia pseudomallei in raja isteri pengiran anak saleha hospital were identified from records in the microbiolo ...201121633768
isolation and characterization of a novel virulent podovirus which infects burkholderia pseudomallei.abstract: burkholderia pseudomallei is a saprophytic soil bacterium and the etiological agent that causes melioidosis. it is naturally resistant to many antibiotics and therefore is difficult to treat. bacteriophages may provide an alternative source of treatment. we have isolated and characterised the bacteriophage phi bp-amp1. the phage is a member of the podoviridae family and has a genome size of ~ 45 kb. molecular data based on the gene which encodes for the phage tail tubular protein sugge ...201121791081
antimicrobial activity of cathelicidin peptides against burkholderia pseudomallei, the causative agent of melioidosis. 201121782393
toll-like receptor 4 region genetic variants are associated with susceptibility to melioidosis.melioidosis is a tropical infection caused by the gram-negative soil saprophyte burkholderia pseudomallei. despite broad exposure of northeastern thais, disease develops in only a small proportion of individuals. although diabetes is a risk factor, the mechanisms of host susceptibility to melioidosis are still poorly understood. we postulated that toll-like receptors (tlrs) regulate host susceptibility to disease, and that genetic variation in tlrs is associated with melioidosis. we analyzed the ...201121776015
a role for the burkholderia pseudomallei type three secretion system cluster 1 bpscn gene in virulence.burkholderia pseudomallei, the causal agent of melioidosis, employs a number of virulence factors during its infection of mammalian cells. one such factor is the type three secretion system (ttss), which is proposed to mediate the transport and secretion of bacterial effector molecules directly into host cells. the b. pseudomallei genome contains three ttss gene clusters (designated ttss1, ttss2 and ttss3). previous research has indicated that neither ttss1 nor ttss2 are involved in b. pseudomal ...201121768285
survival of burkholderia pseudomallei in distilled water for 16 years.burkholderia pseudomallei was examined after being maintained in distilled water at 25°c for 16 years. the gram stain was atypical (pale pink cocci or coccobacilli). the estimated number of live and dead b. pseudomallei was 3.8×10(7) cells/ml and 1.4×10(5) cells/ml, respectively. a colony count on agar of 1.0×10(6) cfu/ml suggested that a proportion of cells were in a viable but non-culturable state. colony morphology was different from the parental isolate for 84% of colonies. pulsed-field gel ...201121764093
diabetes does not influence activation of coagulation, fibrinolysis or anticoagulant pathways in gram-negative sepsis (melioidosis).diabetes is associated with a disturbance of the haemostatic balance and is an important risk factor for sepsis, but the influence of diabetes on the pathogenesis of sepsis remains unclear. melioidosis ( burkholderia pseudomallei infection) is a common cause of community-acquired sepsis in southeast asia and northern australia. we sought to investigate the impact of pre-existing diabetes on the coagulation and fibrinolytic systems during sepsis caused by b.pseudomallei . we recruited a cohort of ...201121979378
facile syntheses of the disaccharide repeating unit of the o-antigenic polysaccharide of burkholderia pseudomallei strain 304b and its dimer and trimer.a highly efficient strategy for the preparation of a disaccharide-repeating unit of the o-antigenic polysaccharide of burkholderia pseudomallei strain 304b, and its dimer and trimer, has been developed through a regio- and stereoselective manner using p-methoxylphenyl 2,4,6-tri-o-benzoyl-α-d-glucopyranoside and 3-o-allyloxycarbonyl-2,4-di-o-benzoyl-6-deoxy-α-l-talopyranosyl trichloroacetimidate as the key synthons. the target molecules were equipped with a p-methoxylphenyl handle at the reducing ...201121963340
etymologia: melioidosis.from the greek melis, distemper of asses, oeide-s, resemblance, and osis, a suffix indicating an abnormal condition or disease. alfred whitmore, a british pathologist serving in burma, and his assistant c. s. krishnaswami first described melioidosis in 1912. the infection became known as whitmore's disease. in 1925, ambrose t. stanton and william fletcher, the researchers who identified burkholderia pseudomallei as the infection's causative agent, renamed the infection melioidosis because of its ...201121762621
dictyostelium discoideum as a model system for identification of burkholderia pseudomallei virulence factors.burkholderia pseudomallei is an emerging bacterial pathogen and category b biothreat. human infections with b. pseudomallei (called melioidosis) present as a range of manifestations, including acute septicemia and pneumonia. although melioidosis can be fatal, little is known about the molecular basis of b. pseudomallei pathogenicity, in part because of the lack of simple, genetically tractable eukaryotic models to facilitate en masse identification of virulence determinants or explore host-patho ...201121402765
complete killing of caenorhabditis elegans by burkholderia pseudomallei is dependent on prolonged direct association with the viable pathogen.burkholderia pseudomallei is the causative agent of melioidosis, a disease of significant morbidity and mortality in both human and animals in endemic areas. much remains to be known about the contributions of genotypic variations within the bacteria and the host, and environmental factors that lead to the manifestation of the clinical symptoms of melioidosis.201121408228
distinct roles for nitric oxide in resistant c57bl/6 and susceptible balb/c mice to control burkholderia pseudomallei infection.burkholderia pseudomallei is the causative agent of melioidosis, an emerging bacterial infectious disease in tropical and subtropical areas. we recently showed that nadph oxidase but not nitric oxide (no) contributes to resistance in innately resistant c57bl/6 mice in a b. pseudomallei respiratory infection model. however, the function of no for resistance was shown to differ among distinct strains of mice and proved also to be stage dependent in various infection models. the present study there ...201121410970
vith world melioidosis congress report: celebrating a century of research. 201121449838
comparative in vitro susceptibility of burkholderia pseudomallei to doripenem, ertapenem, tigecycline and moxifloxacin.burkholderia pseudomallei, the causative agent of melioidosis, continues to present therapeutic challenges in endemic areas. a number of clinical issues have prompted consideration of alternative antimicrobial therapies. these include stability in 24-h infusion pumps, broad-spectrum coverage in the empirical treatment of community-acquired pneumonia, cost, the need for effective oral agents and rare reports of emerging resistance. this study aimed to examine the in vitro susceptibility of b. pse ...201121481571
mycotic aneurysm caused by burkholderia pseudomallei: report of a brazilian strain genetically related to thai strains.clin microbiol infect 2011; 17: 719-721 abstract: melioidosis, a severe infectious disease caused by burkholderia pseudomallei that is prevalent in southeast asia and northern australia, has been sporadically reported in brazil since 2003. we report a case of aortic aneurysm with blood culture positive for b. pseudomallei. the phylogenetic analysis of 16s ribosomal dna showed this isolate to be evolutionarily grouped with the mshr346 strains from thailand.201121521412
adaptation and antibiotic tolerance of anaerobic burkholderia pseudomallei.the gram-negative bacterium, burkholderia pseudomallei, is the etiological agent of melioidosis and is remarkably resistant to most classes of antibacterials. even after months of treatment with antibacterials relatively effective in vitro, there is a high rate of treatment failure, indicating that this pathogen alters its patterns of antibacterial susceptibility in response to cues encountered in the host. the pathology of melioidosis indicates that b. pseudomallei encounter host microenvironme ...201121537012
a conference report from "down under": talking autophagy at ozbio2010.ozbio2010 was held at the melbourne convention and exhibition centre, september 26 to october 1, 2010. this international conference catered to researchers in several fields having complementary interests including biochemistry, molecular biology, cell biology, plant physiology and health-related research. it was held under the auspices of two major international scientific societies, iubmb and faobmb, and the combio2010 collective (representing nine professional societies and groupings from aus ...201121116128
production and characterization of chimeric monoclonal antibodies against burkholderia pseudomallei and b. mallei using the dhfr expression system.burkholderia pseudomallei (bp) and b. mallei (bm) are closely related gram-negative, facultative anaerobic bacteria which cause life-threatening melioidosis in human and glanders in horse, respectively. our laboratory has previously generated and characterized more than 100 mouse monoclonal antibodies (mabs) against bp and bm, according to in vitro and in vivo assay. in this study, 3 mabs (bp7 10b11, bp7 2c6, and bp1 7f7) were selected to develop into chimeric mouse-human monoclonal antibodies ( ...201121573027
the structure of a burkholderia pseudomallei immunophilin-inhibitor complex reveals new approaches to antimicrobial development.macrophage infectivity potentiators (mips) are a subset of immunophilins associated with virulence in a range of micro-organisms. these proteins possess prolyl-peptide isomerase activity and are inhibited by drugs including rapamycin and tacrolimus. we determined the structure of the mip homologue (bpml1) from the human pathogen and biowarfare threat burkholderia pseudomallei by nuclear magnetic resonance and x-ray crystallography. the crystal structure suggests that key catalytic residues in th ...201121574961
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