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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
neonatal melioidosis: systematic review of the literature.twenty-two cases of neonatal melioidosis were identified with the primary outcome from a systematic review, and the clinical presentations were either bacteremia and/or meningitis with burkholderia pseudomallei isolated in all cases. ten cases reported the mode of transmission: infections that occurred from mother-to-child transmission (20%), and infections that were probably healthcare-associated (40%) and community-acquired (40%). the crude mortality was 73% (16/22).201222739573
matrix-assisted laser desorption ionization-time of flight mass spectrometry for rapid identification of burkholderia pseudomallei: importance of expanding databases with pathogens endemic to different localities. 201222718946
differential host response to burkholderia pseudomallei: tissue plasminogen activator*. 201222710226
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
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
genomic islands as a marker to differentiate between clinical and environmental burkholderia pseudomallei.burkholderia pseudomallei, as a saprophytic bacterium that can cause a severe sepsis disease named melioidosis, has preserved several extra genes in its genome for survival. the sequenced genome of the organism showed high diversity contributed mainly from genomic islands (gis). comparative genome hybridization (cgh) of 3 clinical and 2 environmental isolates, using whole genome microarrays based on b. pseudomallei k96243 genes, revealed a difference in the presence of genomic islands between cl ...201222675491
use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis for rapid confirmation of burkholderia pseudomallei in septicemic melioidosis.burkholderia pseudomallei was quickly identified from blood cultures collected from septicemic patients by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis using an in-house reference library. this procedure reduced the time to definitive identification by more than 24 hours. this analysis is a useful addition to laboratory methods for early recognition of septicemic melioidosis in non-endemic settings.201222665614
development and validation of burkholderia pseudomallei-specific real-time pcr assays for clinical, environmental or forensic detection applications.the bacterium burkholderia pseudomallei causes melioidosis, a rare but serious illness that can be fatal if untreated or misdiagnosed. species-specific pcr assays provide a technically simple method for differentiating b. pseudomallei from near-neighbor species. however, substantial genetic diversity and high levels of recombination within this species reduce the likelihood that molecular signatures will differentiate all b. pseudomallei from other burkholderiaceae. currently available molecular ...201222624061
persistent gastric colonization with burkholderia pseudomallei and dissemination from the gastrointestinal tract following mucosal inoculation of mice.melioidosis is a disease of humans caused by opportunistic infection with the soil and water bacterium burkholderia pseudomallei. melioidosis can manifest as an acute, overwhelming infection or as a chronic, recurrent infection. at present, it is not clear where b. pseudomallei resides in the mammalian host during the chronic, recurrent phase of infection. to address this question, we developed a mouse low-dose mucosal challenge model of chronic b. pseudomallei infection and investigated sites o ...201222624016
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
endogenous tissue-type plasminogen activator impairs host defense during severe experimental gram-negative sepsis (melioidosis)*.melioidosis is a frequent cause of severe sepsis in southeast asia caused by the gram-negative bacterium burkholderia pseudomallei. patients with melioidosis have elevated circulating levels of tissue-type plasminogen activator, an important regulator of fibrinolysis. in this study, we aimed to investigate the role of tissue-type plasminogen activator during melioidosis.201222564963
burkholderia pseudomallei detection in surface water in southern laos using moore's swabs.the causal agent of melioidosis, burkholderia pseudomallei, has been cultured from paddy fields in the lao pdr. we carried out a pilot study to examine the relationship between bacterial soil contamination and that of nearby surface waters in saravane province. soil sampling was conducted at a depth of 30 cm (100 holes in a 45 × 45 m grid) at two sites, east and west saravane. moore's swabs were used for water sampling of paddy fields, lakes, rivers, boreholes, and storage tanks within 2 km of t ...201222556090
glutathione deficiency in type 2 diabetes impairs cytokine responses and control of intracellular bacteria.individuals with type 2 diabetes are at increased risk of acquiring melioidosis, a disease caused by burkholderia pseudomallei infection. although up to half of melioidosis patients have underlying diabetes, the mechanisms involved in this increased susceptibility are unknown. we found that b. pseudomallei-infected pbmcs from diabetic patients were impaired in il-12p70 production, which resulted in decreased ifn-γ induction and poor bacterial killing. the defect was specific to the il-12-ifn-γ a ...201222546856
enzymatic profiling of clinical and environmental isolates of burkholderia pseudomallei.melioidosis has been recognized as an important cause of sepsis in the tropics. the disease caused by an environmental saprophyte burkholderia pseudomallei, affects mostly adults with underlying immunocompromised conditions. in this study, the enzymatic profiles of 91 clinical and 9 environmental isolates of b. pseudomallei were evaluated using the apizym system, in addition to assessment of protease, phospholipase c and sialidase activities using agar plate methods and other assays. the activit ...201222543616
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
pediatric suppurative parotitis in cambodia between 2007 and 2011.the causes of suppurative parotitis in cambodian children are not known. we describe 39 cases at the angkor hospital for children, siem reap, between january 2007 and july 2011 (0.07/1000 hospital attendances). the median age was 5.7 years with no neonates affected. burkholderia pseudomallei was cultured in 29 (74%) cases. no deaths occurred; 1 child developed facial nerve palsy.201222531239
polysaccharide specific monoclonal antibodies provide passive protection against intranasal challenge with burkholderia pseudomallei.burkholderia pseudomallei is a gram-negative bacillus that is the causative agent of melioidosis. the bacterium is inherently resistant to many antibiotics and mortality rates remain high in endemic areas. the lipopolysaccharide (lps) and capsular polysaccharide (cps) are two surface-associated antigens that contribute to pathogenesis. we previously developed two monoclonal antibodies (mabs) specific to the cps and lps; the cps mab was shown to identify antigen in serum and urine from melioidosi ...201222530013
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
dna binding site analysis of burkholderia thailandensis response regulators.bacterial response regulators (rr) that function as transcription factors in two component signaling pathways are crucial for ensuring tight regulation and coordinated expression of the genome. currently, consensus dna binding sites in the promoter for very few bacterial rrs have been identified. a systematic method to characterize these dna binding sites for rrs would enable prediction of specific gene expression patterns in response to extracellular stimuli. to identify rr dna binding sites, w ...201222521922
nitric oxide-dependent killing of aerobic, anaerobic and persistent burkholderia pseudomallei.burkholderia pseudomallei infections are fastidious to treat with conventional antibiotic therapy, often involving a combination of drugs and long-term regimes. bacterial genetic determinants contribute to the resistance of b. pseudomallei to many classes of antibiotics. in addition, anaerobiosis and hypoxia in abscesses typical of melioidosis select for persistent populations of b. pseudomallei refractory to a broad spectrum of antibacterials. we tested the susceptibility of b. pseudomallei to ...201222521523
emerging clinico-epidemiological trends in melioidosis: analysis of 95 cases from western coastal india.to study the clinico-epidemiological trends in melioidosis, an emerging disease in the western coastal region of india.201222512851
a melioidosis patient presenting with brainstem signs in the emergency department.neurological abnormalities in melioidosis are rare but may manifest as an acute stroke, and in the emergency department (ed), an inappropriate stroke treatment may threaten a patient's life.201322494598
comparison of the efficiency of sampling devices for aerosolized burkholderia pseudomallei.previous studies have demonstrated that aerosol sampling devices can have deleterious effects on bacteria due to stresses intrinsic to the sampling processes. although a significant amount of work has been carried out to develop animal models of inhalational melioidosis, little information has been reported on the effects of the aerosol sampling devices on the causative bacterium, burkholderia pseudomallei. the aim of this study was to compare the efficiencies for collection of aerosolized bacte ...201222486343
[characterisation of burkholderia pseudomallei lethal factor 1 (blf1). a breakthrough against melioidosis]. 201222480647
burkholderia pseudomallei triggers altered inflammatory profiles in a whole-blood model of type 2 diabetes-melioidosis comorbidity.melioidosis is a potentially fatal disease caused by the bacterium burkholderia pseudomallei. type 2 diabetes (t2d) is the most common comorbidity associated with melioidosis. b. pseudomallei isolates from melioidosis patients with t2d are less virulent in animal models than those from patients with melioidosis and no identifiable risk factors. we developed an ex vivo whole-blood assay as a tool for comparison of early inflammatory profiles generated by t2d and nondiabetic (nd) individuals in re ...201222473609
melioidotic pericardial effusion.aim is to present a rare case of purulent pericardial effusion caused by burkholderia pseudomallei. pericardial sample was inoculated into bactec peds plus/f broth of the bactec automated system. after the system flagged positive, the broth was subjected to gram stain, biochemical tests and drug susceptibility. the organism was identified as burkholderia pseudomallei. tuberculosis (tb) is the most common cause of pericarditis in countries where it remains a major public health problem, but in th ...201022466500
ceftazidime resistance in burkholderia pseudomallei: first report from india.melioidosis, a disease of public health importance in southeast asia and northern australia, of late has shown an increasing trend in india, particularly southern india. we describe a case of a 39-year-old diabetic patient with left elbow septic arthritis, multiple liver, splenic abscesses, pneumonia, pleural effusion, followed by sepsis syndrome. blood cultures and culture of the joint aspirate yielded pure growth of burkholderia pseudomallei (b. pesudomallei), sensitive to carbapenem, co-trimo ...201222449529
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
[study of extracellular antigens by immunodiffusion methods in differentiation of pathogenic burkholderiae].isolation and composition comparison of extracellular antigens (eca) of pathogenic burkholderiae in sds-page electrophoresis and their use for differentiation of these microorganisms by immunodiffusion methods.201222442972
comparison of taqman pcr assays for detection of the melioidosis agent burkholderia pseudomallei in clinical specimens.melioidosis is an emerging infectious disease caused by the soil bacterium burkholderia pseudomallei. in diagnostic and forensic settings, molecular detection assays need not only high sensitivity with low limits of detection but also high specificity. in a direct comparison of published and newly developed taqman pcr assays, we found the tts1-orf2 assay to be superior in detecting b. pseudomallei directly from clinical specimens. the ylf/btfc multiplex assay (targeting the yersinia-like fimbria ...201222442327
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
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
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
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
reduced susceptibility of malaysian clinical isolates of burkholderia pseudomallei to ciprofloxacin.ciprofloxacin, a quinolone with good intracellular penetration may possibly be used for treatment of melioidosis caused by burkholderia pseudomallei, but problems with resistance may be encountered. amino acid substitutions in gyra/gyrb have given rise to fluoroquinolone resistance in various microorganisms. using published primers for gyra and gyrb, pcr was performed on 11 isolates of b. pseudomallei with varying degrees of sensitivity to ciprofloxacin, followed by dna sequencing to detect poss ...201122433895
development of multiplex real-time pcr for the rapid detection of five bacterial causes of community acquired pneumonia.establishing a microbial diagnosis for patients with community-acquired pneumonia (cap) is still challenging and is often achieved in only 30-50% of cases. polymerase chain reaction (pcr) has been shown to be more sensitive than conventional microbiological methods and it could help to increase the microbial yield for cap patients. this study was designed to develop, optimize and evaluate multiplex real-time pcr as a method for rapid differential detection of five bacterial causes of cap namely ...201122433883
the use of multiplex real-time pcr improves the detection of the bacterial etiology of community acquired pneumonia.community-acquired pneumonia (cap) is still a major cause of morbidity and mortality especially to children and compromised hosts, such as the old and those with underlying chronic diseases. knowledge of pathogens causing cap constitutes the basis for selection of antimicrobial treatment. previous data have shown that etiological agents can be identified in only up to 50% of patients, but this figure can be improved by using polymerase chain reaction (pcr). this study was designed to evaluate mu ...201122433882
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
when it comes to drug discovery not all gram-negative bacterial biodefence pathogens are created equal: burkholderia pseudomallei is different. 201222385701
regulation of a quorum sensing system by stationary phase sigma factor rpos and their co-regulation of target genes in burkholderia pseudomallei.burkholderia pseudomallei is the causative agent of a fatal disease, melioidosis. however, the mechanisms of pathogenesis and genes involved in its virulence are not understood. in the current study, whether stationary phase and stress response sigma factor rpos and bpsi-mediated quorum sensing (qs) system co-regulate its target genes was investigated. positive regulation of rpos on bpsi expression and autoinducer production in stationary phase, but not on flic and ppk expression, was observed. ...201222385268
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
severe coinfection of melioidosis and dengue fever in northeastern brazil: first case report.this report focuses on a fatality involving severe dengue fever and melioidosis in a 28-year-old truck driver residing in pacoti in northeastern brazil. he exhibited long-term respiratory symptoms (48 days) and went through a wide-ranging clinical investigation at three hospitals, after initial clinical diagnoses of pneumonia, visceral leishmaniasis, tuberculosis, and fungal sepsis. after death, burkholderia pseudomallei was isolated in a culture of ascitic fluid. dengue virus type 1 was detecte ...201222370846
diffusion and activity of antibiotics against burkholderia pseudomallei biofilms.the diffusion and activity of ceftazidime (caz), imipenem (ipm) and trimethoprim/sulfamethoxazole (tmp/smx) against burkholderia pseudomallei biofilms were comparatively tested using the high biofilm-producing strain b. pseudomallei 377 and the biofilm-defective mutant b. pseudomallei m6. biofilms were generated by inoculation of bacteria on polycarbonate membranes placed on the surface of tryptic soy agar plates. the results showed that diffusion of tmp/smx through b. pseudomallei biofilms was ...201222364716
characterization of ceftazidime resistance mechanisms in clinical isolates of burkholderia pseudomallei from australia.burkholderia pseudomallei is a gram-negative bacterium that causes the serious human disease, melioidosis. there is no vaccine against melioidosis and it can be fatal if not treated with a specific antibiotic regimen, which typically includes the third-generation cephalosporin, ceftazidime (caz). there have been several resistance mechanisms described for b. pseudomallei, of which the best described are amino acid changes that alter substrate specificity in the highly conserved class a β-lactama ...201222363490
development of hydrolysis probe-based real-time pcr for identification of virulent gene targets of burkholderia pseudomallei and b. mallei--a retrospective study on archival cases of service members with melioidosis and glanders.burkholderia pseudomallei and b. mallei are two highly pathogenic bacteria responsible for melioidosis and glanders, respectively. our laboratory developed hydrolysis probe-based real-time polymerase chain reaction assays targeting type three secretion system (tts) and transposase family protein (tfp) of b. pseudomallei and b. malli, respectively. the assays were validated for target specificity, amplification sensitivity, and reproducibility. a bacterial dna panel, composed of b. pseudomallei ( ...201222360070
validation of a burkholderia pseudomallei hypothetical protein and determination of its translational start codon using chromosomal integration of his-tag coding sequence.in this post genomic era, there are a great number of in silico annotated hypothetical genes. however, experimental validation of the functionality of these genes remains tentative. two of the major challenges faced by researcher are whether these hypothetical genes are protein-coding genes and whether their corresponding predicted translational start codons are correct. in this report, we demonstrate a convenient procedure to validate the presence of a hypothetical gene product of bpss1356 from ...201222354666
passive protection of diabetic rats with antisera specific for the polysaccharide portion of the lipopolysaccharide isolated from pseudomonas pseudomallei.polyclonal and monoclonal antisera raised to tetanus toxoid-conjugated polysaccharide of lipopolysaccharide (lps) and purified lps of pseudomonas pseudomallei that reacted with a collection of 41 strains of this bacterium from 23 patients are described. the common antigen recognized by these sera was within the polysaccharide component of the lps of the cells. the sera were specific for p pseudomallei in that none of 37 strains of other bacteria, including 20 gram-negative and three gram-positiv ...199422346496
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
melioidosis vaccines: a systematic review and appraisal of the potential to exploit biodefense vaccines for public health purposes.burkholderia pseudomallei is a category b select agent and the cause of melioidosis. research funding for vaccine development has largely considered protection within the biothreat context, but the resulting vaccines could be applicable to populations who are at risk of naturally acquired melioidosis. here, we discuss target populations for vaccination, consider the cost-benefit of different vaccination strategies and review potential vaccine candidates.201222303489
interaction of burkholderia pseudomallei and burkholderia thailandensis with human monocyte-derived dendritic cells.burkholderia pseudomallei is the causative agent of melioidosis, a disease endemic in areas of south-east asia and northern australia, and is classed as a category b select agent by the centers for disease control and prevention (cdc). factors that determine whether host infection is achieved or if disease is chronic or acute are unknown but the type of host immune response that is mounted is important. b. pseudomallei can replicate within macrophages, causing them to multinucleate. in light of ...201222301613
heterologously type iv pilus expressed protein of burkholderia pseudomallei is immunogenic but fails to induce protective immunity in mice.burkholderia pseudomallei is the causative agent of melioidosis, a severe disease of humans and animals. at present, no effective vaccine against melioidosis exists. bacterial type iv pilin proteins have been used successfully as subunit vaccines. in this study, we evaluated a heterologously expressed and purified type iv pilus protein (pilv) of b. pseudomallei strain k96243 as a candidate subunit vaccine. pilv protein was assessed for its ability to protect balb/c mice against b. pseudomallei s ...201122299445
surface plasmon resonance immunosensor for rapid and specific diagnosis of melioidosis antibody.melioidosis, caused by burkholderia pseudomallei, is a potentially fatal disease, which requires an accurate and rapid diagnosis. this paper reports on the highly sensitive and specific detection of melioidosis antibodies by surface plasmon resonance immunosensor. the sensing surface was immobilized with b. pseudomallei bipd protein via a 11-mercaptoundecanoic acid self-assembled monolayer. under optimum conditions individual sera of melioidosis patients, non-melioidosis patients (negative) and ...201122299443
defense mechanisms of hepatocytes against burkholderia pseudomallei.the gram-negative facultative intracellular rod burkholderia pseudomallei causes melioidosis, an infectious disease with a wide range of clinical presentations. among the observed visceral abscesses, the liver is commonly affected. however, neither this organotropism of b. pseudomallei nor local hepatic defense mechanisms have been thoroughly investigated so far. own previous studies using electron microscopy of the murine liver after systemic infection of mice indicated that hepatocytes might b ...201122291688
sesquiterpene farnesol contributes to increased susceptibility to β-lactams in strains of burkholderia pseudomallei.this study aimed to evaluate the in vitro combination of farnesol and β-lactams against burkholderia pseudomallei. a total of 12 β-lactamase-positive strains were tested according to clsi standards. all strains were inhibited by farnesol, with mics ranging from 75 to 150 μm. the combination of this compound with β-lactams resulted in statistically significant β-lactam mic reduction (p ≤ 0.05). this study provides new perspectives for the use of farnesol combined with β-lactam antibiotics against ...201222290941
melioidosis presenting with mediastinal lymphadenopathy masquerading as malignancy: a case report.melioidosis, endemic in thailand and in the northern territory of australia is an emerging infectious disease in india which can present with varied forms. a case of melioidosis, presenting as a rare anterior mediastinal mass which can masquerade as malignancy or tuberculosis, is described here. with treatment, our patient initially showed an increase in the size of mediastinal node and development of new submandibular node.. to the best of our knowledge, this phenomenon has not been documented ...201222269609
immune response to burkholderia pseudomallei.burkholderia pseudomallei are the causative agents of melioidosis, a disease found mostly in people with underlying risk factors. fifty percent of cases are community-acquired septicemias and manifestation can vary from acute septicemia (with or without shock), to chronic, to subclinical infections. there is no vaccine to prevent the condition. it is difficult to eradicate the bacteria. prolonged antibiotic therapy is required. finally, there is a high rate of relapse when therapy is not complet ...201122256484
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
inflammasome-dependent pyroptosis and il-18 protect against burkholderia pseudomallei lung infection while il-1β is deleterious.burkholderia pseudomallei is a gram-negative bacterium that infects macrophages and other cell types and causes melioidosis. the interaction of b. pseudomallei with the inflammasome and the role of pyroptosis, il-1β, and il-18 during melioidosis have not been investigated in detail. here we show that the nod-like receptors (nlr) nlrp3 and nlrc4 differentially regulate pyroptosis and production of il-1β and il-18 and are critical for inflammasome-mediated resistance to melioidosis. in vitro produ ...201122241982
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
structural analysis of capsular polysaccharides expressed by burkholderia mallei and burkholderia pseudomallei.capsular polysaccharides (cpss) were isolated from o-polysaccharide deficient strains of burkholderia mallei and burkholderia pseudomallei using a modified hot phenol/water extraction procedure. glycosyl composition, methylation, maldi-tof ms analyses as well as (1)h nmr spectroscopy including cosy, tocsy, noesy, hmbc and hsqc experiments identified the presence of two distinct cps antigens in the samples exhibiting the following structures: this study confirms the ability of b. mallei to expres ...201122221792
thirty years of heme catalases structural biology.about thirty years ago the crystal structures of the heme catalases from penicillium vitale (pvc) and, a few months later, from bovine liver (blc) were published. both enzymes were compact tetrameric molecules with subunits that, despite their size differences and the large phylogenetic separation between the two organisms, presented a striking structural similarity for about 460 residues. the high conservation, confirmed in all the subsequent structures determined, suggested a strong pressure t ...201122209752
diversity of 16s-23s rdna internal transcribed spacer (its) reveals phylogenetic relationships in burkholderia pseudomallei and its near-neighbors.length polymorphisms within the 16s-23s ribosomal dna internal transcribed spacer (its) have been described as stable genetic markers for studying bacterial phylogenetics. in this study, we used these genetic markers to investigate phylogenetic relationships in burkholderia pseudomallei and its near-relative species. b. pseudomallei is known as one of the most genetically recombined bacterial species. in silico analysis of multiple b. pseudomallei genomes revealed approximately four homologous r ...201122195045
microbiological spectrum of brain abscess at a tertiary care hospital in south india: 24-year data and review.intracranial abscesses are life-threatening infections that pose a diagnostic challenge not only to the neurosurgeon but also to the microbiologists. detailed studies documenting the spectrum of infecting agents involved in brain abscesses are limited from india. materials and methods. this is a retrospective analysis of 352 samples from 1987 to 2010 analyzed at a tertiary care hospital in south india from 1987 to 2010, to document the changing trends with time. results. the age of the patients ...201122191080
[Detection and identification of highly pathogenic bacteria within the framework of the EQADeBa project--Part I: Samples containing living pathogens].Bacillus anthracis, Yersinia pestis, Francisella tularensis, Brucella sp., Bulkholderia mallei are B. pseudomallei are highly pathogenic bacteria of potential bioterrorism risk. To support the early warning and rapid response capacity to ensure an effective reaction to bioterrorist attacks the international project "Establishment of Quality Assurances for Detection of Highly Pathogenic Bacteria of Potential Bioterrorism Risk" (EQADeBa) has been established. The aim of the project was establishme ...201122184939
epidemiological tracking and population assignment of the non-clonal bacterium, burkholderia pseudomallei.rapid assignment of bacterial pathogens into predefined populations is an important first step for epidemiological tracking. for clonal species, a single allele can theoretically define a population. for non-clonal species such as burkholderia pseudomallei, however, shared allelic states between distantly related isolates make it more difficult to identify population defining characteristics. two distinct b. pseudomallei populations have been previously identified using multilocus sequence typin ...201122180792
out of the ground: aerial and exotic habitats of the melioidosis bacterium burkholderia pseudomallei in grasses in australia.melioidosis is an emerging infectious disease of humans and animals in the tropics caused by the soil bacterium burkholderia pseudomallei. despite high fatality rates, the ecology of b. pseudomallei remains unclear. we used a combination of field and laboratory studies to investigate b. pseudomallei colonization of native and exotic grasses in northern australia. multivariable and spatial analyses were performed to determine significant predictors for b. pseudomallei occurrence in plants and soi ...201122176696
identification of differentially expressed proteins from burkholderia pseudomallei isolated during primary and relapsing melioidosis.burkholderia pseudomallei causes septicemic melioidosis with a high rate of relapse, however microbial determinants of relapse are unknown. proteins were analyzed from sequential b. pseudomallei isolates from primary and relapsing melioidosis. analysis by isotope tagging for relative and absolute quantitation revealed that factors required for nitric oxide detoxification (hmpa) and necessary for anaerobic growth (arca, arcc and arcb) were highly expressed in the relapse isolate. two-dimensional ...201122172334
cloning, purification and crystallographic analysis of a hypothetical protein, bpsl1549, from burkholderia pseudomallei.burkholderia pseudomallei bpsl1549, a putative protein of unknown function, has been overexpressed in escherichia coli, purified and subsequently crystallized by the hanging-drop vapour-diffusion method using peg as a precipitant to give crystals with overall dimensions of 0.15 × 0.15 × 0.1 mm. native data were collected to 1.47 å resolution at the european synchrotron radiation facility (esrf). the crystals belonged to space group p2(1)2(1)2(1), with unit-cell parameters a = 37.1, b = 45.4, c = ...201122139182
delayed activation of host innate immune pathways in streptozotocin-induced diabetic hosts leads to more severe disease during infection with burkholderia pseudomallei.diabetes mellitus is a predisposing factor of melioidosis contributing to higher mortality rates in diabetics infected with burkholderia pseudomallei. to investigate how diabetes alters the inflammatory response, we established a streptozotocin (stz)-induced diabetic murine acute-phase melioidosis model. viable b. pseudomallei cells were consistently detected in the blood, liver and spleen during the 42 hr course of infection but the hyperglycemic environment did not increase the bacterial burde ...201122136109
immunogenic consensus sequence t helper epitopes for a pan-burkholderia biodefense vaccine.background. biodefense vaccines against category b bioterror agents burkholderia pseudomallei (bpm) and burkholderia mallei (bm) are needed, as they are both easily accessible to terrorists and have strong weaponization potential. burkholderia cepaciae (bc), a related pathogen, causes chronic lung infections in cystic fibrosis patients. since bpm, bm and bc are all intracellular bacteria, they are excellent targets for t cell-based vaccines. however, the sheer volume of available genomic data re ...201122130150
burkholderia pseudomallei: an uncommon cause of bacteraemic pneumonia in a diabetic. 201122128627
development of an acute model of inhalational melioidosis in the common marmoset (callithrix jacchus).studies of inhalational melioidosis were undertaken in the common marmoset (callithrix jacchus). following exposure to an inhaled challenge with aerosolized burkholderia pseudomallei, lethal infection was observed in marmosets challenged with doses below 10 cfu; a precise ld(50) determination was not possible. the model was further characterized using a target challenge dose of approximately 10(2) cfu. a separate pathogenesis time-course experiment was also conducted. all animals succumbed, betw ...201122122591
diagnostic use of burkholderia pseudomallei selective media in a low prevalence setting.routine use of selective media improves diagnosis of burkholderia pseudomallei, but resources may be limited in endemic developing countries. to maximise yield in the relatively low-prevalence setting of kuala lumpur, malaysia, b. pseudomallei selective agar and broth were compared with routine media for 154 respiratory specimens from patients with community-acquired disease. selective media detected three additional culture-positive specimens and one additional melioidosis patient, at a consuma ...201122112687
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
effectiveness of a simplified method for isolation of burkholderia pseudomallei from soil.detection of environmental burkholderia pseudomallei indicates a risk for melioidosis and is important for the development of a global risk map. we describe a simple method for detecting b. pseudomallei using direct culture of soil in enrichment broth. this gives a rate of positivity comparable to that obtained with a standard method but is cheaper and labor saving.201122101048
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
Musculoskeletal melioidosis.Melioidosis is an infectious disease caused by Burkholderia pseudomallei, mostly affecting patients in Southeast Asia and northern Australia. The disease has been increasingly recognized around the world due to the increased levels of travel and population movement. Clinical manifestations of melioidosis range from fulminant septicemic illness to an indolent local infection. The disease often involves multiple organs, including the lung, spleen, liver, and other visceral organs. Musculoskeletal ...201122081283
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
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
Molecular investigations of a locally acquired case of melioidosis in Southern AZ, USA.Melioidosis is caused by Burkholderia pseudomallei, a Gram-negative bacillus, primarily found in soils in Southeast Asia and northern Australia. A recent case of melioidosis in non-endemic Arizona was determined to be the result of locally acquired infection, as the patient had no travel history to endemic regions and no previous history of disease. Diagnosis of the case was confirmed through multiple microbiologic and molecular techniques. To enhance the epidemiological analysis, we conducted s ...201122028940
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
strategies for intracellular survival of burkholderia pseudomallei.burkholderia pseudomallei is the causative agent of melioidosis, a disease with high mortality that is prevalent in tropical regions of the world. a key component of the pathogenesis of melioidosis is the ability of b. pseudomallei to enter, survive, and replicate within mammalian host cells. for non-phagocytic cells, bacterial adhesins have been identified both on the bacterial surface and associated with type 4 pili. cell invasion involves components of one or more of the three type 3 secretio ...201122007185
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
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
Development of vaccines against burkholderia pseudomallei.Burkholderia pseudomallei is a Gram-negative bacterium which is the causative agent of melioidosis, a disease which carries a high mortality and morbidity rate in endemic areas of South East Asia and Northern Australia. At present there is no available human vaccine that protects against B. pseudomallei, and with the current limitations of antibiotic treatment, the development of new preventative and therapeutic interventions is crucial. This review considers the multiple elements of melioidosis ...201121991263
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
Antimicrobial resistance to ceftazidime involving loss of penicillin-binding protein 3 in Burkholderia pseudomallei.Known mechanisms of resistance to ß-lactam antibiotics include ß-lactamase expression, altered drug target, decreased bacterial permeability, and increased drug efflux. Here, we describe a unique mechanism of ß-lactam resistance in the biothreat organism Burkholderia pseudomallei (the cause of melioidosis), associated with treatment failure during prolonged ceftazidime therapy of natural infection. Detailed comparisons of the initial ceftazidime-susceptible infecting isolate and subsequent cefta ...201121969582
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
a proteome reference map of the causative agent of melioidosis burkholderia pseudomallei.burkholderia pseudomallei is the etiologic agent of melioidosis. using 2de and maldi-tof ms, we report here a proteome reference map constructed from early stationary phase, a bacterial adaptation process. we identified 282 protein spots representing 220 orfs; many of them have been implicated in bacterial pathogenesis. up to 20% of identified orfs belong to post-translational modification and stress responses. the proteome reference map will support future analysis of the bacterial gene and env ...201121960737
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
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
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
structures of phosphopantetheine adenylyltransferase from burkholderia pseudomallei.phosphopantetheine adenylyltransferase (ppat) catalyzes the fourth of five steps in the coenzyme a biosynthetic pathway, reversibly transferring an adenylyl group from atp onto 4'-phosphopantetheine to yield dephospho-coenzyme a and pyrophosphate. burkholderia pseudomallei is a soil- and water-borne pathogenic bacterium and the etiologic agent of melioidosis, a potentially fatal systemic disease present in southeast asia. two crystal structures are presented of the ppat from b. pseudomallei with ...201121904046
inhibition of cullin ring ligases by cycle inhibiting factor: evidence for interference with nedd8-induced conformational control.cycle inhibiting factor (cif) is produced by pathogenic intracellular bacteria and injected into the host cells via a type iii secretion system. cif is known to interfere with the eukaryotic cell cycle by inhibiting the function of cullin ring e3 ubiquitin ligases (crls). cullin proteins form the scaffold protein of crls and are modified with the ubiquitin-like protein nedd8, which exerts important conformational control required for crl activity. cif has recently been shown to catalyze the deam ...201121903097
Survey of antimicrobial resistance in clinical Burkholderia pseudomallei isolates over two decades in Northeast Thailand.A 21-year survey conducted in northeast Thailand of antimicrobial resistance to parenteral antimicrobial drugs used to treat melioidosis identified 24/4,021 (0.6%) patients with one or more isolates resistant to ceftazidime (n = 8), amoxicillin-clavulanic acid (n = 4), or both drugs (n = 12). Two cases were identified at admission, and the remainder were detected a median of 15 days after starting antimicrobial therapy. Resistance to carbapenem drugs was not detected. These findings support the ...201121876049
Groundwater seeps facilitate exposure to Burkholderia pseudomallei.Burkholderia pseudomallei is a saprophytic bacterium which is the causative agent of melioidosis, a common cause of fatal bacterial pneumonia and sepsis in the tropics. The incidence of melioidosis is clustered spatially and temporally and is heavily linked to rainfall and extreme weather events. Clinical case clustering has recently been reported in Townsville, Australia, and has implicated Castle Hill, a granite monolith in the city center, as a potential reservoir of infection. Topsoil and wa ...201121873480
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
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
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