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1

Evolution of Burkholderia pseudomallei in Recurrent Melioidosis  

PubMed Central

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 disease, or they may be genetically similar. To test these alternative models, we conducted whole-genome comparisons of clonal primary and relapse B. pseudomallei isolates recovered six months to six years apart from four adult Thai patients. We found differences within each of the four pairs, and some, including a 330 Kb deletion, affected substantial portions of the genome. Many of the changes were associated with increased antibiotic resistance. We also found evidence of positive selection for deleterious mutations in a TetR family transcriptional regulator from a set of 107 additional B. pseudomallei strains. As part of the study, we sequenced to base-pair accuracy the genome of B. pseudomallei strain 1026b, the model used for genetic studies of B. pseudomallei pathogenesis and antibiotic resistance. Our findings provide new insights into pathogen evolution during long-term infections and have important implications for the development of intervention strategies to combat recurrent melioidosis. PMID:22615773

Hayden, Hillary S.; Lim, Regina; Brittnacher, Mitchell J.; Sims, Elizabeth H.; Ramage, Elizabeth R.; Fong, Christine; Wu, Zaining; Crist, Eva; Chang, Jean; Zhou, Yang; Radey, Matthew; Rohmer, Laurence; Haugen, Eric; Gillett, Will; Wuthiekanun, Vanaporn; Peacock, Sharon J.; Kaul, Rajinder; Miller, Samuel I.; Manoil, Colin; Jacobs, Michael A.

2012-01-01

2

Melioidosis Caused by Burkholderia pseudomallei in Drinking Water, Thailand, 2012  

PubMed Central

We identified 10 patients in Thailand with culture-confirmed melioidosis who had Burkholderia pseudomallei isolated from their drinking water. The multilocus sequence type of B. pseudomallei from clinical specimens and water samples were identical for 2 patients. This finding suggests that drinking water is a preventable source of B. pseudomallei infection. PMID:24447771

Wongsuvan, Gumphol; Aanensen, David; Ngamwilai, Sujittra; Saiprom, Natnaree; Rongkard, Patpong; Thaipadungpanit, Janjira; Kanoksil, Manas; Chantratita, Narisara; Day, Nicholas P.J.; Peacock, Sharon J.

2014-01-01

3

Melioidosis: insights into the pathogenicity of Burkholderia pseudomallei  

Microsoft Academic Search

Burkholderia pseudomallei is a potential bioterror agent and the causative agent of melioidosis, a severe disease that is endemic in areas of Southeast Asia and Northern Australia. Infection is often associated with bacterial dissemination to distant sites, and there are many possible disease manifestations, with melioidosis septic shock being the most severe. Eradication of the organism following infection is difficult,

Tom van der Poll; Nicholas J. White; Nicholas P. Day; Sharon J. Peacock; W. Joost Wiersinga

2006-01-01

4

Detection of Burkholderia pseudomallei DNA in Patients with Septicemic Melioidosis  

Microsoft Academic Search

Septicemic melioidosis is the most severe form of melioidosis, which is caused byBurkholderia pseudomallei. It is endemic in Southeast Asia and is the leading cause of death from community-acquired septicemia in northeast Thailand. A major factor that contributes to the high mortality is the delay in isolation and identificationofthecausativeorganism.Morethanhalfofthepatientsdiewithinthefirst2daysafterhospital admission, before bacterial cultures become positive. The present study was undertaken

TARARAJ DHARAKUL; SIRIRURG SONGSIVILAI; SIRITHIP VIRIYACHITRA; VORAVICH LUANGWEDCHAKARN; BOONRAT TASSANEETRITAP; ANDWIPADA CHAOWAGUL

1996-01-01

5

Burkholderia pseudomallei capsular polysaccharide conjugates provide protection against acute melioidosis.  

PubMed

Burkholderia pseudomallei, the etiologic agent of melioidosis, is a CDC tier 1 select agent that causes severe disease in both humans and animals. Diagnosis and treatment of melioidosis can be challenging, and in the absence of optimal chemotherapeutic intervention, acute disease is frequently fatal. Melioidosis is an emerging infectious disease for which there are currently no licensed vaccines. Due to the potential malicious use of B. pseudomallei as well as its impact on public health in regions where the disease is endemic, there is significant interest in developing vaccines for immunization against this disease. In the present study, type A O-polysaccharide (OPS) and manno-heptose capsular polysaccharide (CPS) antigens were isolated from nonpathogenic, select-agent-excluded strains of B. pseudomallei and covalently linked to carrier proteins. By using these conjugates (OPS2B1 and CPS2B1, respectively), it was shown that although high-titer IgG responses against the OPS or CPS component of the glycoconjugates could be raised in BALB/c mice, only those animals immunized with CPS2B1 were protected against intraperitoneal challenge with B. pseudomallei. Extending upon these studies, it was also demonstrated that when the mice were immunized with a combination of CPS2B1 and recombinant B. pseudomallei LolC, rather than with CPS2B1 or LolC individually, they exhibited higher survival rates when challenged with a lethal dose of B. pseudomallei. Collectively, these results suggest that CPS-based glycoconjugates are promising candidates for the development of subunit vaccines for immunization against melioidosis. PMID:24866807

Scott, Andrew E; Burtnick, Mary N; Stokes, Margaret G M; Whelan, Adam O; Williamson, E Diane; Atkins, Timothy P; Prior, Joann L; Brett, Paul J

2014-08-01

6

Genomic patterns of pathogen evolution revealed by comparison of Burkholderia pseudomallei, the causative agent of melioidosis, to avirulent Burkholderia thailandensis  

E-print Network

Background: The Gram-negative bacterium Burkholderia pseudomallei (Bp) is the causative agent of the human disease melioidosis. To understand the evolutionary mechanisms contributing to Bp virulence, we performed a comparative ...

Yu, Yiting

7

Highly resistant Burkholderia pseudomallei small colony variants isolated in vitro and in experimental melioidosis  

Microsoft Academic Search

Burkholderia pseudomallei is the causative agent of melioidosis, a disease in which treatment failures and relapses are common. This study reports\\u000a on slow growing B. pseudomallei `small colony variants' (SCVs), isolated either in vitro after exposure to ceftazidime, ciprofloxacin or gentamicin or from\\u000a the spleen and liver in a mouse model of melioidosis after treatment with ceftazidime. Interestingly, SCVs isolated

Susanne Häußler; Manfred Rohde; Ivo Steinmetz

1999-01-01

8

Multilocus Sequence Typing and Evolutionary Relationships among the Causative Agents of Melioidosis and Glanders, Burkholderia pseudomallei and Burkholderia mallei  

Microsoft Academic Search

A collection of 147 isolates of Burkholderia pseudomallei, B. mallei, and B. thailandensis was characterized by multilocus sequence typing (MLST). The 128 isolates of B. pseudomallei, the causative agent of melioidosis, were obtained from diverse geographic locations, from humans and animals with disease, and from the environment and were resolved into 71 sequence types. The utility of the MLST scheme

Daniel Godoy; Gaynor Randle; Andrew J. Simpson; David M. Aanensen; Tyrone L. Pitt; Reimi Kinoshita; Brian G. Spratt

2003-01-01

9

Current antimicrobial susceptibility of first-episode melioidosis Burkholderia pseudomallei isolates from the Northern Territory, Australia.  

PubMed

Burkholderia pseudomallei is a saprophytic Gram-negative bacterium responsible for the tropical infectious disease melioidosis. Melioidosis is endemic to northern Australia and Southeast Asia. In this study, 234 isolates of B. pseudomallei obtained from the first positive clinical specimen from 234 consecutive patients diagnosed with melioidosis between October 2009 and September 2012 were reviewed. All isolates were susceptible to meropenem and ceftazidime. In total, 226 isolates (96.6%) were susceptible to doxycycline and 232 (99.1%) were susceptible to trimethoprim/sulfamethoxazole (TMP/SMX; co-trimoxazole). Primary resistance of B. pseudomallei to ceftazidime and/or meropenem is exceedingly rare and clinicians can be confident in the current treatment guidelines for melioidosis. Whether the very low rates of TMP/SMX resistance seen in Australia reflect the global situation requires further studies using Etest, especially to clarify the rate of resistance in Thailand. PMID:24924662

Crowe, Amy; McMahon, Nicole; Currie, Bart J; Baird, Robert W

2014-08-01

10

Ribotyping and DNA macrorestriction analysis of isolates of Burkholderia pseudomallei from cases of melioidosis in Malaysia  

Microsoft Academic Search

Forty-nine isolates of Burkholderia pseudomallei from sporadic cases of melioidosis in Malaysia over the past 18 years were examined by BamHI ribotyping and pulsed-field gel electrophoresis (PFGE) of XbaI digests of total deoxyribonucleic acid (DNA). Twenty-four patients had septicaemic melioidosis with a mortality of 70%; mortality in the non-septicaemic disease was 16%. Five ribotype patterns were identified, 2 of which

Jamuna Vadivelu; S. D. Puthucheary; A. Mifsud; B. S. Drasar; D. A. B. Dance; T. L. Pitt

1997-01-01

11

Characterisation and molecular typing of Burkholderia pseudomallei: Are disease presentations of melioidosis clonally related?  

Microsoft Academic Search

Eighteen cases of culture positive melioidosis caused by Burkholderia pseudomallei, were seen in four geographically separate communities in North Queensland, Australia. The genetic inter-relatedness of the clinical isolates were compared utilising random amplification of polymorphic DNA (RAPD) and multilocus enzyme electrophoresis (MEE). The isolates segregated into two groups that correlated with clinical presentation rather than geographical location. This is the

R Norton; B Roberts; M Freeman; M Wilson; C Ashhurst-Smith; W Lock; D Brookes; J La Brooy

1998-01-01

12

Dose-response model for Burkholderia pseudomallei (melioidosis)  

Microsoft Academic Search

Aims: The objective of this study was development of a dose-response model for exposure to Burkholderia pseudomallei in different animal hosts and analysis of the results. The data sets with which the model was developed were taken from the open literature. Methods and Results: All data sets were initially tested for a trend between dose and outcome using the Cochran-Armitage

S. B. Tamrakar; C. N. Haas

2008-01-01

13

Role of Burkholderia pseudomallei biofilm formation and lipopolysaccharide in relapse of melioidosis.  

PubMed

We examined whether quantitative biofilm formation and/or lipopolysaccharide type of Burkholderia pseudomallei was associated with relapsing melioidosis. We devised a 1 : 4 nested case-control study in which both cases and controls were drawn from a cohort of patients with primary melioidosis. Paired isolates from 80 patients with relapse and single isolates from 184 patients without relapse were tested. Relapse was associated with biofilm formation of the primary infecting isolate (conditional OR 2.03; 95% CI 1.27-3.25; p 0.003), but not with lipopolysaccharide type (p 0.74). This finding highlights the importance of biofilm formation in relapsing melioidosis. PMID:24602145

Limmathurotsakul, D; Paeyao, A; Wongratanacheewin, S; Saiprom, N; Takpho, N; Thaipadungpanit, J; Chantratita, N; Wuthiekanun, V; Day, N P J; Peacock, S J

2014-11-01

14

Role of Burkholderia pseudomallei biofilm formation and lipopolysaccharide in relapse of melioidosis  

PubMed Central

We examined whether quantitative biofilm formation and/or lipopolysaccharide type of Burkholderia pseudomallei was associated with relapsing melioidosis. We devised a 1 : 4 nested case–control study in which both cases and controls were drawn from a cohort of patients with primary melioidosis. Paired isolates from 80 patients with relapse and single isolates from 184 patients without relapse were tested. Relapse was associated with biofilm formation of the primary infecting isolate (conditional OR 2.03; 95% CI 1.27–3.25; p 0.003), but not with lipopolysaccharide type (p 0.74). This finding highlights the importance of biofilm formation in relapsing melioidosis. PMID:24602145

Limmathurotsakul, D; Paeyao, A; Wongratanacheewin, S; Saiprom, N; Takpho, N; Thaipadungpanit, J; Chantratita, N; Wuthiekanun, V; Day, N P J; Peacock, S J

2014-01-01

15

Genomic patterns of pathogen evolution revealed by comparison of Burkholderia pseudomallei, the causative agent of melioidosis, to avirulent Burkholderia thailandensis  

Microsoft Academic Search

BACKGROUND: The Gram-negative bacterium Burkholderia pseudomallei (Bp) is the causative agent of the human disease melioidosis. To understand the evolutionary mechanisms contributing to Bp virulence, we performed a comparative genomic analysis of Bp K96243 and B. thailandensis (Bt) E264, a closely related but avirulent relative. RESULTS: We found the Bp and Bt genomes to be broadly similar, comprising two highly

Yiting Yu; H Stanley Kim; Hui Hoon Chua; Chi Ho Lin; Siew Hoon Sim; Daoxun Lin; Alan Derr; Reinhard Engels; David DeShazer; Bruce Birren; William C Nierman; Patrick Tan

2006-01-01

16

Toxin production by Burkholderia pseudomallei strains and correlation with severity of melioidosis  

Microsoft Academic Search

An exotoxin lethal to cells in culture (cytolethal toxin, CLT) was identified in culture filtrates of Burkholderia pseudomallei, the causative organism of melioidosis. CLT could pass through a 10-kDa cut-off ultrafilter and its properties suggest that it is a peptide. Isolates from soil, animals and man showed differential cytolethality in vitro. The isolates were divided into low, medium and high

ANTJE HAASE; JULIA JANZEN; SIOBHAN BARRETT; B. CURRIE

1997-01-01

17

Antibiotic susceptibility of Burkholderia pseudomallei from tropical northern Australia and implications for therapy of melioidosis  

Microsoft Academic Search

From a prospective melioidosis study commencing in 1989 at Royal Darwin Hospital, 170 initial isolates of Burkholderia pseudomallei were available for susceptibility testing. Of these 163 (96%) were susceptible to meropenem\\/imipenem, ceftazidime, trimethoprim-sulphamethoxazole (SMX\\/TMP) and doxycycline. Seven (4%) showed primary resistance; three had low-level resistance to SMX\\/TMP, one to ceftriaxone and amoxycillin\\/clavulanate (AMOX\\/CA) and three to doxycycline. Of 167 patients

Adam W. J. Jenney; Gary Lum; Dale A. Fisher; Bart J. Currie

2001-01-01

18

In situ hybridization to detect and identify Burkholderia pseudomallei in human melioidosis.  

PubMed

Burkholderia pseudomallei causes a potentially fatal infection called melioidosis. We have developed a nonfluorescent, colorimetric in situ hybridization assay using a specific probe to target 16s rRNA of B. pseudomallei in formalin-fixed, paraffin-embedded infected tissues for diagnostic purposes and to study infectious disease pathology. A 63-base pair DNA probe was synthesized and labeled with digoxigenin by PCR. Probe specificity was confirmed by BLAST analysis and by testing on appropriate microbial controls. The in situ hybridization assay was specifically and consistently positive for B. pseudomallei, showing strongly and crisply stained, single bacillus and bacilli clusters in mainly inflamed tissues in seven human acute melioidosis cases and experimentally infected mouse tissues. Intravascular and extravascular bacilli were detected in both intracellular and extracellular locations in various human organs, including lung, spleen, kidney, liver, bone marrow, and aortic mycotic aneurysm, particularly in the inflamed areas. Intravascular, intracellular bacteria in melioidosis have not been previously reported. Although the identity of infected intravascular leukocytes has to be confirmed, extravascular, intracellular bacilli appear to be found mainly within macrophages and neutrophils. Rarely, large intravascular, extracellular bacillary clusters/emboli could be detected in both human and mouse tissues. B. cepacia and non-Burkholderia pathogens (16 microbial species) all tested negative. Nonpathogenic B. thailandensis showed some cross-hybridization but signals were less intense. This in situ hybridization assay could be usefully adapted for B. pseudomallei identification in other clinical specimens such as pus and sputum. PMID:24186135

Eu, Lin Chuan; Ong, Kien Chai; Hiu, Jessie; Vadivelu, Jamunarani; Nathan, Sheila; Wong, Kum Thong

2014-05-01

19

Burkholderia pseudomallei Known Siderophores and Hemin Uptake Are Dispensable for Lethal Murine Melioidosis  

PubMed Central

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 bacterium's pathogenesis. It was previously assumed that B. pseudomallei used iron-acquisition systems commonly found in other bacteria, for example siderophores. However, our previous discovery of a clinical isolate carrying a large chromosomal deletion missing the entire malleobactin gene cluster encoding the bacterium's major high-affinity siderophore while still being fully virulent in a murine melioidosis model suggested that other iron-acquisition systems might make contributions to virulence. Here, we deleted the major siderophore malleobactin (mba) and pyochelin (pch) gene clusters in strain 1710b and revealed a residual siderophore activity which was unrelated to other known Burkholderia siderophores such as cepabactin and cepaciachelin, and not due to increased secretion of chelators such as citrate. Deletion of the two hemin uptake loci, hmu and hem, showed that Hmu is required for utilization of hemin and hemoglobin and that Hem cannot complement a Hmu deficiency. Prolonged incubation of a hmu hem mutant in hemoglobin-containing minimal medium yielded variants able to utilize hemoglobin and hemin suggesting alternate pathways for utilization of these two host iron sources. Lactoferrin utilization was dependent on malleobactin, but not pyochelin synthesis and/or uptake. A mba pch hmu hem quadruple mutant could use ferritin as an iron source and upon intranasal infection was lethal in an acute murine melioidosis model. These data suggest that B. pseudomallei may employ a novel ferritin-iron acquisition pathway as a means to sustain in vivo growth. PMID:22745846

Kvitko, Brian H.; Goodyear, Andrew; Propst, Katie L.; Dow, Steven W.; Schweizer, Herbert P.

2012-01-01

20

Burkholderia pseudomallei known siderophores and hemin uptake are dispensable for lethal murine melioidosis.  

PubMed

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 bacterium's pathogenesis. It was previously assumed that B. pseudomallei used iron-acquisition systems commonly found in other bacteria, for example siderophores. However, our previous discovery of a clinical isolate carrying a large chromosomal deletion missing the entire malleobactin gene cluster encoding the bacterium's major high-affinity siderophore while still being fully virulent in a murine melioidosis model suggested that other iron-acquisition systems might make contributions to virulence. Here, we deleted the major siderophore malleobactin (mba) and pyochelin (pch) gene clusters in strain 1710b and revealed a residual siderophore activity which was unrelated to other known Burkholderia siderophores such as cepabactin and cepaciachelin, and not due to increased secretion of chelators such as citrate. Deletion of the two hemin uptake loci, hmu and hem, showed that Hmu is required for utilization of hemin and hemoglobin and that Hem cannot complement a Hmu deficiency. Prolonged incubation of a hmu hem mutant in hemoglobin-containing minimal medium yielded variants able to utilize hemoglobin and hemin suggesting alternate pathways for utilization of these two host iron sources. Lactoferrin utilization was dependent on malleobactin, but not pyochelin synthesis and/or uptake. A mba pch hmu hem quadruple mutant could use ferritin as an iron source and upon intranasal infection was lethal in an acute murine melioidosis model. These data suggest that B. pseudomallei may employ a novel ferritin-iron acquisition pathway as a means to sustain in vivo growth. PMID:22745846

Kvitko, Brian H; Goodyear, Andrew; Propst, Katie L; Dow, Steven W; Schweizer, Herbert P

2012-01-01

21

Antimicrobial susceptibility patterns of Burkholderia pseudomallei among melioidosis cases in Kedah, Malaysia.  

PubMed

Burkholderia pseudomallei, the causative agent of melioidosis is an important cause of morbidity and mortality particularly among diabetics. We evaluated 228 isolates of B. pseudomallei for antimicrobial sensitivity during 2005-2010 using the disc diffusion technique, of which 144 were obtained from blood culture. More than 90% of the strains were susceptible to cefoperazone, ceftazidime, chloramphenicol and imipenem. Eighty-two percent of the isolates were susceptible to tetracycline and amoxicillin/clavulanate. The susceptibilities to ciprofloxacin was 78% and to trimethoprim-sulfamethoxezole was 47%. The susceptibilities to aminoglycoside antibiotics were low (21% to gentamicin and 6% to amikacin). The susceptibilities were similar between isolates from females and males, bacteremic and abacteremic cases, diabetics and non-diabetics, pneumonia and non-pneumonia cases and between those who died and those who survived. Our findings show antibiotic susceptibility patterns are not a major factor in determining outcomes of B. pseudomallei infection. Monitoring the drug susceptibilities among B. pseudomallei isolates needs to be conducted regularly to guide empiric therapy for melioidosis, as it causes high mortality, especially among diabetic cases. PMID:24974653

Hassan, Muhammad R A; Vijayalakshmi, Natesan; Pani, Subhada Prasad; Peng, Ng P; Mehenderkar, Ranjith; Voralu, Kirtanaa; Michael, Edwin

2014-05-01

22

Multilocus Sequence Typing and Evolutionary Relationships among the Causative Agents of Melioidosis and Glanders, Burkholderia pseudomallei and Burkholderia mallei  

PubMed Central

A collection of 147 isolates of Burkholderia pseudomallei, B. mallei, and B. thailandensis was characterized by multilocus sequence typing (MLST). The 128 isolates of B. pseudomallei, the causative agent of melioidosis, were obtained from diverse geographic locations, from humans and animals with disease, and from the environment and were resolved into 71 sequence types. The utility of the MLST scheme for epidemiological investigations was established by analyzing isolates from captive marine mammals and birds and from humans in Hong Kong with melioidosis. MLST gave a level of resolution similar to that given by pulsed-field gel electrophoresis and identified the same three clones causing disease in animals, each of which was also associated with disease in humans. The average divergence between the alleles of B. thailandensis and B. pseudomallei was 3.2%, and there was no sharing of alleles between these species. Trees constructed from differences in the allelic profiles of the isolates and from the concatenated sequences of the seven loci showed that the B. pseudomallei isolates formed a cluster of closely related lineages that were fully resolved from the cluster of B. thailandensis isolates, confirming their separate species status. However, isolates of B. mallei, the causative agent of glanders, recovered from three continents over a 30-year period had identical allelic profiles, and the B. mallei isolates clustered within the B. pseudomallei group of isolates. Alleles at six of the seven loci in B. mallei were also present within B. pseudomallei isolates, and B. mallei is a clone of B. pseudomallei that, on population genetics grounds, should not be given separate species status. PMID:12734250

Godoy, Daniel; Randle, Gaynor; Simpson, Andrew J.; Aanensen, David M.; Pitt, Tyrone L.; Kinoshita, Reimi; Spratt, Brian G.

2003-01-01

23

Out of the Ground: Aerial and Exotic Habitats of the Melioidosis Bacterium Burkholderia pseudomallei in Grasses in Australia  

PubMed Central

Summary 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 soil collected longitudinally from field sites. In plant inoculation experiments, the impact of B. pseudomallei upon these grasses was studied and the bacterial load semi-quantified. Fluorescence-in-situ-hybridization and confocal laser-scanning microscopy were performed to localize the bacteria in plants. B. pseudomallei was found to inhabit not only the rhizosphere and roots but also aerial parts of specific grasses. This raises questions about the potential spread of B. pseudomallei by grazing animals whose droppings were found to be positive for these bacteria. In particular, B. pseudomallei readily colonized exotic grasses introduced to Australia for pasture. The ongoing spread of these introduced grasses creates new habitats suitable for B. pseudomallei survival and may be an important factor in the evolving epidemiology of melioidosis seen both in northern Australia and elsewhere globally. PMID:22176696

Kaestli, Mirjam; Schmid, Michael; Mayo, Mark; Rothballer, Michael; Harrington, Glenda; Richardson, Leisha; Hill, Audrey; Hill, Jason; Tuanyok, Apichai; Keim, Paul; Hartmann, Anton; Currie, Bart J.

2011-01-01

24

Burkholderia pseudomallei is a Tier 1 Select Agent that causes the often fatal human disease melioidosis. B. pseudomallei and related species invade a variety of cell types, replicate in  

E-print Network

Burkholderia pseudomallei is a Tier 1 Select Agent that causes the often fatal human disease melioidosis. B. pseudomallei and related species invade a variety of cell types, replicate in the cytoplasm investigated temporal and spatial requirements for virulence determinants in the Burkholderia intracellular

Chan, Hue Sun

25

Osteomyelitis and septic arthritis from infection with Burkholderia pseudomallei: A 20-year prospective melioidosis study from northern Australia  

PubMed Central

Background The gram-negative organism, Burkholderia pseudomallei, is responsible for the disease melioidosis. Septic arthritis and osteomyelitis due to B. pseudomallei are rare but recognised presentations of the disease. Methods A prospective database of all cases of melioidosis in the Northern Territory of Australia has been kept since October 1989. Entries to April 2009 were reviewed and cases involving bone and/or joint were investigated. We also present in detail the case reports of 3 presentations of bone and joint melioidosis. Results There were 536 presentations of melioidosis during the 20-year study period. Amongst these, there were 13 patients with primary septic arthritis and 7 cases of primary osteomyelitis. Septic arthritis and osteomyelitis were secondary to primary melioidosis elsewhere in 14 and 7 patients respectively. Melioidosis patients with bone/joint involvement were more likely to be Indigenous (p = 0.006) and female (p = 0.023) compared to patients with other presentations of disease. Conclusions Timely microbiological diagnosis and prompt treatment of melioidosis involving bone and/or joint with appropriate intravenous antibiotics is important, as is adequate surgical drainage and debridement where indicated. A subsequent protracted course of antibiotic eradication therapy is important to avoid relapse of disease. PMID:24403756

Morse, Levi P.; Smith, Jonathan; Mehta, Janak; Ward, Linda; Cheng, Allen C.; Currie, Bart J.

2013-01-01

26

Burkholderia pseudomallei penetrates the brain via destruction of the olfactory and trigeminal nerves: implications for the pathogenesis of neurological melioidosis.  

PubMed

ABSTRACT Melioidosis is a potentially fatal disease that is endemic to tropical northern Australia and Southeast Asia, with a mortality rate of 14 to 50%. The bacterium Burkholderia pseudomallei is the causative agent which infects numerous parts of the human body, including the brain, which results in the neurological manifestation of melioidosis. The olfactory nerve constitutes a direct conduit from the nasal cavity into the brain, and we have previously reported that B. pseudomallei can colonize this nerve in mice. We have now investigated in detail the mechanism by which the bacteria penetrate the olfactory and trigeminal nerves within the nasal cavity and infect the brain. We found that the olfactory epithelium responded to intranasal B. pseudomallei infection by widespread crenellation followed by disintegration of the neuronal layer to expose the underlying basal layer, which the bacteria then colonized. With the loss of the neuronal cell bodies, olfactory axons also degenerated, and the bacteria then migrated through the now-open conduit of the olfactory nerves. Using immunohistochemistry, we demonstrated that B. pseudomallei migrated through the cribriform plate via the olfactory nerves to enter the outer layer of the olfactory bulb in the brain within 24 h. We also found that the bacteria colonized the thin respiratory epithelium in the nasal cavity and then rapidly migrated along the underlying trigeminal nerve to penetrate the cranial cavity. These results demonstrate that B. pseudomallei invasion of the nerves of the nasal cavity leads to direct infection of the brain and bypasses the blood-brain barrier. IMPORTANCE Melioidosis is a potentially fatal tropical disease that is endemic to northern Australia and Southeast Asia. It is caused by the bacterium Burkholderia pseudomallei, which can infect many organs of the body, including the brain, and results in neurological symptoms. The pathway by which the bacteria can penetrate the brain is unknown, and we have investigated the ability of the bacteria to migrate along nerves that innervate the nasal cavity and enter the frontal region of the brain by using a mouse model of infection. By generating a mutant strain of B. pseudomallei which is unable to survive in the blood, we show that the bacteria rapidly penetrate the cranial cavity using the olfactory (smell) nerve and the trigeminal (sensory) nerve that line the nasal cavity. PMID:24736221

St John, James A; Ekberg, Jenny A K; Dando, Samantha J; Meedeniya, Adrian C B; Horton, Rachel E; Batzloff, Michael; Owen, Suzzanne J; Holt, Stephanie; Peak, Ian R; Ulett, Glen C; Mackay-Sim, Alan; Beacham, Ifor R

2014-01-01

27

Whole-Genome Sequencing of Burkholderia pseudomallei Isolates from an Unusual Melioidosis Case Identifies a Polyclonal Infection with the Same Multilocus Sequence Type.  

PubMed

Twelve Burkholderia pseudomallei isolates collected over a 32-month period from a patient with chronic melioidosis demonstrated identical multilocus sequence types (STs). However, whole-genome sequencing suggests a polyclonal infection. This study is the first to report a mixed infection with the same ST. PMID:25339397

Price, Erin P; Sarovich, Derek S; Viberg, Linda; Mayo, Mark; Kaestli, Mirjam; Tuanyok, Apichai; Foster, Jeffrey T; Keim, Paul; Pearson, Talima; Currie, Bart J

2015-01-01

28

Growth, motility and resistance to oxidative stress of the melioidosis pathogen Burkholderia pseudomallei are enhanced by epinephrine.  

PubMed

Burkholderia pseudomallei causes melioidosis, a severe invasive disease endemic in South-East Asia and Northern Australia. Bacterial pathogens of several genera have been reported to be able to sense and respond to the stress-related catecholamine hormone epinephrine. Here, we report that epinephrine induces growth of B. pseudomallei in minimal serum-rich medium and heat-inactivated whole human serum and enhances bacterial motility, transcription of flagellar genes and flagellin synthesis. The effect of epinephrine on motility, but not bacterial growth, could be partially reversed by the alpha-adrenergic receptor antagonist phentolamine. Epinephrine also altered the transcription of iron-regulated genes encoding superoxide dismutase (sodB) and the malleobactin receptor (fmtA). Consistent with induction of sodB expression, epinephrine-treated B. pseudomallei exhibited increased resistance to superoxide. Epinephrine treatment did not stimulate Type III secretion via the virulence-associated Bsa apparatus or the ability of B. pseudomallei to invade epithelial cells in culture. This study provides the first evidence that epinephrine, a hormone released from the host under stress and upon therapy, can affect B. pseudomallei virulence-associated properties. PMID:24753312

Intarak, Narin; Muangsombut, Veerachat; Vattanaviboon, Paiboon; Stevens, Mark P; Korbsrisate, Sunee

2014-10-01

29

Development of antibodies to Burkholderia pseudomallei during childhood in melioidosis-endemic northeast Thailand.  

PubMed

A cross-sectional serological survey of 2,214 children living in northeast Thailand was conducted to define the antibody response to Burkholderia pseudomallei from birth to 14 years. There was a sharp rise in detectable antibodies from birth to 4 years followed by reactivity in approximately 60-70% of children thereafter. PMID:16760522

Wuthiekanun, Vanaporn; Chierakul, Wirongrong; Langa, Sayan; Chaowagul, Wipada; Panpitpat, Chanathip; Saipan, Penchan; Thoujaikong, Thaksinaporn; Day, Nicholas P; Peacock, Sharon J

2006-06-01

30

Burkholderia pseudomallei Penetrates the Brain via Destruction of the Olfactory and Trigeminal Nerves: Implications for the Pathogenesis of Neurological Melioidosis  

PubMed Central

ABSTRACT Melioidosis is a potentially fatal disease that is endemic to tropical northern Australia and Southeast Asia, with a mortality rate of 14 to 50%. The bacterium Burkholderia pseudomallei is the causative agent which infects numerous parts of the human body, including the brain, which results in the neurological manifestation of melioidosis. The olfactory nerve constitutes a direct conduit from the nasal cavity into the brain, and we have previously reported that B. pseudomallei can colonize this nerve in mice. We have now investigated in detail the mechanism by which the bacteria penetrate the olfactory and trigeminal nerves within the nasal cavity and infect the brain. We found that the olfactory epithelium responded to intranasal B. pseudomallei infection by widespread crenellation followed by disintegration of the neuronal layer to expose the underlying basal layer, which the bacteria then colonized. With the loss of the neuronal cell bodies, olfactory axons also degenerated, and the bacteria then migrated through the now-open conduit of the olfactory nerves. Using immunohistochemistry, we demonstrated that B. pseudomallei migrated through the cribriform plate via the olfactory nerves to enter the outer layer of the olfactory bulb in the brain within 24 h. We also found that the bacteria colonized the thin respiratory epithelium in the nasal cavity and then rapidly migrated along the underlying trigeminal nerve to penetrate the cranial cavity. These results demonstrate that B. pseudomallei invasion of the nerves of the nasal cavity leads to direct infection of the brain and bypasses the blood-brain barrier. PMID:24736221

St. John, James A.; Ekberg, Jenny A. K.; Dando, Samantha J.; Meedeniya, Adrian C. B.; Horton, Rachel E.; Batzloff, Michael; Owen, Suzzanne J.; Holt, Stephanie; Peak, Ian R.; Ulett, Glen C.; Mackay-Sim, Alan; Beacham, Ifor R.

2014-01-01

31

Burkholderia pseudomallei Isocitrate Lyase Is a Persistence Factor in Pulmonary Melioidosis: Implications for the Development of Isocitrate Lyase Inhibitors as Novel Antimicrobials ? †  

PubMed Central

Burkholderia pseudomallei, the causative agent of melioidosis, has often been called the great “mimicker,” and clinical disease due to this organism may include acute, chronic, and latent pulmonary infections. Interestingly, chronic pulmonary melioidosis is often mistaken for tuberculosis, and this can have significant consequences, as the treatments for these two infections are radically different. The recurrent misdiagnosis of melioidosis for tuberculosis has caused many to speculate that these two bacterial pathogens use similar pathways to produce latent infections. Here we show that isocitrate lyase is a persistence factor for B. pseudomallei, and inhibiting the activity of this enzyme during experimental chronic B. pseudomallei lung infection forces the infection into an acute state, which can then be treated with antibiotics. We found that if antibiotics are not provided in combination with isocitrate lyase inhibitors, the resulting B. pseudomallei infection overwhelms the host, resulting in death. These results suggest that the inhibition of isocitrate lyase activity does not necessarily attenuate virulence as previously observed for Mycobacterium tuberculosis infections but does force the bacteria into a replicating state where antibiotics are effective. Therefore, isocitrate lyase inhibitors could be developed for chronic B. pseudomallei infections but only for use in combination with effective antibiotics. PMID:19620343

van Schaik, Erin J.; Tom, Marina; Woods, Donald E.

2009-01-01

32

Burkholderia pseudomallei virulence: definition, stability and association with clonality  

Microsoft Academic Search

Clinical presentations of melioidosis, caused by Burkholderia pseudomallei are protean, but the mechanisms underlying development of the different forms of disease remain poorly understood. In murine melioidosis, the level of virulence of B. pseudomallei is important in disease pathogenesis and progression. In this study, we used B. pseudomallei-susceptible BALB\\/c mice to determine the virulence of a library of clinical and environmental B. pseudomallei

Glen C. Ulett; Bart J. Currie; Timothy W. Clair; Mark Mayo; Natkunam Ketheesan; Justin Labrooy; Daniel Gal; Robert Norton; Chris Ashhurst Smith; Jodie Barnes; Jeffrey Warner; Robert G. Hirst

2001-01-01

33

Cloning, expression and purification of outer membrane protein (OmpA) of Burkholderia pseudomallei and evaluation of its potential for serodiagnosis of melioidosis.  

PubMed

Melioidosis is an emerging infectious disease in India and caused by gram-negative, soil saprophyte bacteria Burkholderia pseudomallei. This disease is endemic in Southeast Asia and northern Australia, and sporadic cases of melioidosis are also reported from southern states of India. The present study reports the cloning, expression, and purification of recombinant protein outer membrane protein A (OmpA) of B. pseudomallei and its evaluation in indirect enzyme-linked immunosorbent assay (ELISA) format with 87 serum samples collected from Manipal, Karnataka, India. Twenty-three samples from culture confirmed cases (n=23) of melioidosis, 25 serum samples from patients of other febrile illness and pyrexia of unknown origin (n=25), and 39 serum samples from healthy blood donors (n=39) from Kasturba Medical College, Manipal, were tested in this assay format. The assay showed sensitivity of 82.6% and specificity of 93.75%. The recombinant OmpA based indirect ELISA will be a useful tool for serodiagnosis of melioidosis in large scale rapid screening of clinical samples. PMID:25488273

Arora, Sonia; Thavaselvam, Duraipandian; Kumar, Ashu; Prakash, Archana; Barua, Anita; Sathyaseelan, Kannusamy

2015-02-01

34

Neurotropic Threat Characterization of Burkholderia pseudomallei Strains.  

PubMed

The death rate for neurologic melioidosis is high. Whether certain Burkholderia pseudomallei strains are more likely than other strains to cause central nervous system infection and whether route of infection influences the neurotropic threat remain unclear. Therefore, we compared the virulence and dissemination of Australian clinical isolates collected during October 1989-October 2012 from patients with neurologic and nonneurologic melioidosis after intranasal and subcutaneous infection of mice in an experimental model. We did not observe neurotropism as a unique characteristic of isolates from patients with neurologic melioidosis. Rather, a distinct subset of B. pseudomallei strains appear to have heightened pathogenic potential for rapid dissemination to multiple tissues, including the central nervous system, irrespective of the infection route. This finding has valuable public health ramifications for initiating appropriate and timely therapy after exposure to systemically invasive B. pseudomallei strains. Increasing understanding of B. pseudomallei pathology and its influencing factors will further reduce illness and death from this disease. PMID:25530166

Morris, Jodie; Fane, Anne; Rush, Catherine; Govan, Brenda; Mayo, Mark; Currie, Bart J; Ketheesan, Natkunam

2015-01-01

35

Neurotropic Threat Characterization of Burkholderia pseudomallei Strains  

PubMed Central

The death rate for neurologic melioidosis is high. Whether certain Burkholderia pseudomallei strains are more likely than other strains to cause central nervous system infection and whether route of infection influences the neurotropic threat remain unclear. Therefore, we compared the virulence and dissemination of Australian clinical isolates collected during October 1989–October 2012 from patients with neurologic and nonneurologic melioidosis after intranasal and subcutaneous infection of mice in an experimental model. We did not observe neurotropism as a unique characteristic of isolates from patients with neurologic melioidosis. Rather, a distinct subset of B. pseudomallei strains appear to have heightened pathogenic potential for rapid dissemination to multiple tissues, including the central nervous system, irrespective of the infection route. This finding has valuable public health ramifications for initiating appropriate and timely therapy after exposure to systemically invasive B. pseudomallei strains. Increasing understanding of B. pseudomallei pathology and its influencing factors will further reduce illness and death from this disease. PMID:25530166

Fane, Anne; Rush, Catherine; Govan, Brenda; Mayo, Mark; Currie, Bart J.; Ketheesan, Natkunam

2015-01-01

36

Flagella Are Virulence Determinants of Burkholderia pseudomallei  

Microsoft Academic Search

Received 11 June 2002\\/Returned for modification 8 October 2002\\/Accepted 23 December 2002 Burkholderia pseudomallei, a facultatively intracellular pathogen, is a flagellated and motile gram-negative bacterium and is the causative agent of melioidosis in humans. Flagella are commonly recognized as important virulence determinants expressed by bacterial pathogens since the motility phenotype imparted by these organelles often correlates with the ability of

K. L. Chua; Y. Y. Chan; Y. H. Gan

2003-01-01

37

Molecular Procedure for Rapid Detection of Burkholderia mallei and Burkholderia pseudomallei  

Microsoft Academic Search

Both Burkholderia mallei and Burkholderia pseudomallei cause severe infectious diseases in humans, namely, glanders or me- lioidosis. B. pseudomallei is found in soil and water (e.g., rice paddies). Humans can be infected by soil contamination of skin abrasions, ingestion, or inhalation (5). Melioidosis is en- demic in Southeast Asia and northern Australia (14). Cases in humans or animals occur sporadically

ADOLF BAUERNFEIND; CARSTEN ROLLER; DETLEF MEYER; RENATE JUNGWIRTH; INES SCHNEIDER

1998-01-01

38

Virulent Burkholderia pseudomallei is more efficient than avirulent Burkholderia thailandensis in invasion of and adherence to cultured human epithelial cells  

Microsoft Academic Search

Burkholderia pseudomallei, a causative agent of melioidosis, is a facultative intracellular gram-negative bacillus that is closely related to its avirulent counterpart, Burkholderia thailandensis. However, pathogenic mechanisms and virulence factors of B. pseudomallei remain elusive. In the present study, we compared the invasiveness, adherence, and replication of B. pseudomallei and B. thailandensis in human respiratory epithelial cells A549. Invasion was determined

Wannapa Kespichayawattana; Pakamas Intachote; Pongsak Utaisincharoen; Stitaya Sirisinha

2004-01-01

39

Quantitative recovery of Burkholderia pseudomallei from soil in Thailand  

Microsoft Academic Search

Melioidosis is common in north-eastern Thailand, but is reported rarely from the adjacent areas of central Thailand, although rice farming is common to both regions. Quantitative soil cultures for Burkholderia pseudomallei were therefore prepared on 12 rice farms in both regions. B. pseudomallei was isolated from a similar proportion of rice fields in the central region (612) and in the

Michael D. Smith; Vanaporn Wuthiekanun; Amanda L. Walsh; Nicholas J. White

1995-01-01

40

Microevolution of Burkholderia pseudomallei during an Acute Infection  

PubMed Central

We used whole-genome sequencing to evaluate 69 independent colonies of Burkholderia pseudomallei isolated from seven body sites of a patient with acute disseminated melioidosis. Fourteen closely related genotypes were found, providing evidence for the rapid in vivo diversification of B. pseudomallei after inoculation and systemic spread. PMID:24966357

Holden, Matthew T. G.; Coupland, Paul; Price, Erin P.; Chantratita, Narisara; Wuthiekanun, Vanaporn; Amornchai, Premjit; Parkhill, Julian; Peacock, Sharon J.

2014-01-01

41

Role of quorum sensing in the pathogenicity of Burkholderia pseudomallei  

Microsoft Academic Search

Burkholderia pseudomallei is the causative agent of human and animal melioidosis. The role of quorum sensing (QS) in the in vivo pathogenicity of B. pseudomallei via inhalational exposure of BALB\\/c mice and intraperitoneal challenge of Syrian hamsters has not been reported. This investigation demonstrates that B. pseudomallei encodes a minimum of three luxI and five luxR homologues that are involved

Ricky L. Ulrich; David DeShazer; Ernst E. Brueggemann; Harry B. Hines; Petra C. Oyston; Jeffrey A. Jeddeloh

2004-01-01

42

Efflux-Mediated Aminoglycoside and Macrolide Resistance in Burkholderia pseudomallei  

Microsoft Academic Search

Burkholderia pseudomallei, the causative agent of melioidosis, is intrinsically resistant to a wide range of antimicrobial agents including b-lactams, aminoglycosides, macrolides, and polymyxins. We used Tn5-OT182 to mutagenize B. pseudomallei to identify the genes involved in aminoglycoside resistance. We report here on the identification of AmrAB-OprA, a multidrug efflux system in B. pseudomallei which is specific for both ami- noglycoside

RICHARD A. MOORE; DAVID DESHAZER; SHAUNA RECKSEIDLER; ANIA WEISSMAN; DONALD E. WOODS

43

Genomic Diversity of Burkholderia pseudomallei Clinical Isolates: Subtractive Hybridization Reveals a Burkholderia mallei-Specific Prophage in B. pseudomallei 1026b  

Microsoft Academic Search

Burkholderia pseudomallei is the etiologic agent of the disease melioidosis and is a category B biological threat agent. The genomic sequence of B. pseudomallei K96243 was recently determined, but little is known about the overall genetic diversity of this species. Suppression subtractive hybridization was employed to assess the genetic variability between two distinct clinical isolates of B. pseudomallei, 1026b and

David DeShazer

2004-01-01

44

A comparison of antibiotic susceptibility testing methods for cotrimoxazole with Burkholderia pseudomallei  

Microsoft Academic Search

Melioidosis is caused by the Gram-negative soil saprophyte, Burkholderia pseudomallei and is endemic in tropical and subtropical regions of southeast Asia and northern Australia. Cotrimoxazole has been traditionally used for the therapy of melioidosis despite results indicating resistance often produced in the disc diffusion test against B. pseudomallei. This inconsistency was addressed by comparing this method with the agar dilution,

Peter Piliouras; Glen C. Ulett; Christopher Ashhurst-Smith; Robert G. Hirst; Robert E. Norton

2002-01-01

45

Contribution of Gene Loss to the Pathogenic Evolution of Burkholderia pseudomallei and Burkholderia mallei  

Microsoft Academic Search

Burkholderia pseudomallei is the causative agent of melioidosis. Burkholderia thailandensis is a closely related species that can readily utilize L-arabinose as a sole carbon source, whereas B. pseudomallei cannot. We used Tn5-OT182 mutagenesis to isolate an arabinose-negative mutant of B. thailandensis. Sequence analysis of regions flanking the transposon insertion revealed the presence of an arabinose assimilation operon consisting of nine

Richard A. Moore; Shauna Reckseidler-Zenteno; Heenam Kim; William Nierman; Yan Yu; Apichai Tuanyok; Jonathan Warawa; David DeShazer; Donald E. Woods

2004-01-01

46

BALB\\/c and C57Bl\\/6 mice infected with virulent Burkholderia pseudomallei provide contrasting animal models for the acute and chronic forms of human melioidosis  

Microsoft Academic Search

Burkholderia pseudomalleiis the aetiological agent of melioidosis, a life-threatening bacterial disease occurring in many species of animals, including man. Infection in humans commonly manifests as one of three clinical presentations: acute, subacute or chronic disease. Investigations were undertaken to assess the suitability of BALB\\/c and C57Bl\\/6 mice as animal models for the different forms of human melioidosis. The course of

Alison K Leakey; Glen C Ulett; Robert G Hirst

1998-01-01

47

Evaluation of a latex agglutination assay for the identification of Burkholderia pseudomallei and Burkholderia mallei.  

PubMed

Cases of melioidosis and glanders are rare in the United States, but the etiologic agents of each disease (Burkholderia pseudomallei and Burkholderia mallei, respectively) are classified as Tier 1 select agents because of concerns about their potential use as bioterrorism agents. A rapid, highly sensitive, and portable assay for clinical laboratories and field use is required. Our laboratory has further evaluated a latex agglutination assay for its ability to identify B. pseudomallei and B. mallei isolates. This assay uses a monoclonal antibody that specifically recognizes the capsular polysaccharide produced by B. pseudomallei and B. mallei, but is absent in closely related Burkholderia species. A total of 110 B. pseudomallei and B. mallei were tested, and 36 closely related Burkholderia species. The latex agglutination assay was positive for 109 of 110 (99.1% sensitivity) B. pseudomallei and B. mallei isolates tested. PMID:24710616

Duval, Brea D; Elrod, Mindy G; Gee, Jay E; Chantratita, Narisara; Tandhavanant, Sarunporn; Limmathurotsakul, Direk; Hoffmaster, Alex R

2014-06-01

48

Biological activities of lipopolysaccharide of Burkholderia (Pseudomonas) pseudomallei  

Microsoft Academic Search

Endotoxic activities of lipopolysaccharide (LPS) isolated from Burkholderia (Pseudomonas) pseudomallei, a causative agent of melioidosis, were investigated. Compared to an enterobacterial LPS (SAE-LPS), B. pseudomallei LPS (BP-LPS) exhibited weaker pyrogenic activity in rabbits, lethal toxicity in galactosamine-sensitized mice and murine macrophage activation, i.e. production of tumor necrosis factor, interleukin-6 and nitric oxide. BP-LPS, on the other hand, exhibited stronger mitogenic

Motohiro Matsuura; Kazuyoshi Kawahara; Takayuki Ezaki; masayasu Nakano

1996-01-01

49

Model of Differential Susceptibility to Mucosal Burkholderia pseudomallei Infection  

Microsoft Academic Search

Burkholderia pseudomallei is the causative agent of melioidosis, an infectious disease with protean clinical manifestations. The major route of infection is thought to be through subcutaneous inoculation of contami- nated soil and water, although ingestion and inhalation of contaminated aerosols are also possible. This study examines infection through the intranasal route in a murine model to mimic infection through inhalation.

Boping Liu; Ghee Chong Koo; Eu Hian Yap; Kim Lee Chua; Yunn-Hwen Gan

2002-01-01

50

Biochemical characteristics of clinical and environmental isolates of Burkholderia pseudomallei  

Microsoft Academic Search

The biochemical characteristics of 213 isolates of Burkholderia pseudomallei from patients with melioidosis and 140 isolates from the soil in central and northeastern Thailand were compared. Whereas the biochemical profiles of all the clinical isolates were similar, all soil isolates from the central area and 25% of isolates from northeastern Thailand comprised a different phenotype. This was characterised by the

VANAPORN WUTHIEKANUN; M. D. Smith; D. A. B. Dance; AMANDA L. WALSH; T. L. PITTT; N. J. White

1996-01-01

51

Burkholderia pseudomallei Isolates in 2 Pet Iguanas, California, USA  

PubMed Central

Burkholderia pseudomallei, the causative agent of melioidosis, was isolated from abscesses of 2 pet green iguanas in California, USA. The international trade in iguanas may contribute to importation of this pathogen into countries where it is not endemic and put persons exposed to these animals at risk for infection. PMID:24447394

Zehnder, Ashley M.; Hawkins, Michelle G.; Koski, Marilyn A.; Lifland, Barry; Byrne, Barbara A.; Swanson, Alexandra A.; Rood, Michael P.; Elrod, Mindy Glass; Beesley, Cari A.; Blaney, David D.; Ventura, Jean; Hoffmaster, Alex R.; Beeler, Emily S.

2014-01-01

52

Characterization of two distinct phospholipase C enzymes from Burkholderia pseudomallei  

Microsoft Academic Search

Burkholderia pseudomallei is a serious bacterial pathogen that can cause a lethal infection in humans known as melioidosis. In this study two of its phospholipase C (PLC) enzymes (Plc-1 and Plc-2) were characterized. Starting with a virulent strain, two single mutants were constructed, each with one plc gene inactivated, and one double mutant with both plc genes inactivated. The single

Sunee Korbsrisate; Andrew P. Tomaras; Suwat Damnin; Jutturong Ckumdee; Varintip Srinon; Idsada Lengwehasatit; Michael L. Vasil; S. Suparak

2007-01-01

53

A Mutant of Burkholderia pseudomallei, Auxotrophic in the Branched Chain Amino Acid Biosynthetic Pathway, Is Attenuated and Protective in a Murine Model of Melioidosis  

Microsoft Academic Search

Using a transposon mutagenesis approach, we have identified a mutant of Burkholderia pseudomallei that is auxotrophic for branched chain amino acids. The transposon was shown to have interrupted the ilvI gene encoding the large subunit of the acetolactate synthase enzyme. Compared to the wild type, this mutant was significantly attenuated in a murine model of disease. Mice inoculated intraperitoneally with

T. Atkins; R. G. Prior; K. Mack; P. Russell; M. Nelson; P. C. F. Oyston; G. Dougan; R. W. Titball

2002-01-01

54

Migration of dendritic cells facilitates systemic dissemination of Burkholderia pseudomallei.  

PubMed

Burkholderia pseudomallei, the etiological agent for melioidosis, is an important cause of community-acquired sepsis in northern Australia and northeast Thailand. Due to the rapid dissemination of disease in acute melioidosis, we hypothesized that dendritic cells (DC) could act as a vehicle for dissemination of B. pseudomallei. Therefore, this study investigated the effect of B. pseudomallei infection on DC migration capacity and whether migration of DC enabled transportation of B. pseudomallei from the site of infection. B. pseudomallei stimulated significantly increased migration of bone marrow-derived DC (BMDC), both in vitro and in vivo, compared to uninfected BMDC. Furthermore, migration of BMDC enabled significantly increased in vitro trafficking of B. pseudomallei and in vivo dissemination of B. pseudomallei to secondary lymphoid organs and lungs of C57BL/6 mice. DC within the footpad infection site of C57BL/6 mice also internalized B. pseudomallei and facilitated dissemination. Although DC have previously been shown to kill intracellular B. pseudomallei in vitro, the findings of this study demonstrate that B. pseudomallei-infected DC facilitate the systemic spread of this pathogen. PMID:25069976

Williams, Natasha L; Morris, Jodie L; Rush, Catherine M; Ketheesan, Natkunam

2014-10-01

55

Genome-wide expression analysis of iron regulation in Burkholderia pseudomallei and Burkholderia mallei using DNA microarrays  

Microsoft Academic Search

Burkholderia pseudomallei and B. mallei are the causative agents of melioidosis and glanders, respectively. As iron regulation of gene expression is common in bacteria, in the present studies, we have used microarray analysis to examine the effects of growth in different iron concentrations on the regulation of gene expression in B. pseudomallei and B. mallei. Gene expression profiles for these

Apichai Tuanyok; H. Stanley Kim; William C. Nierman; Yan Yu; John Dunbar; Richard A. Moore; Patricia Baker; Marina Tom; Jessmi M. L. Ling; Donald E. Woods

2005-01-01

56

Ecology of Burkholderia pseudomallei and the interactions between environmental Burkholderia spp. and human–animal hosts  

Microsoft Academic Search

Early workers thought that melioidosis was a zoonosis with a reservoir in rodents, but we now know that Burkholderia pseudomallei is a widely distributed environmental saprophyte. In northeast Thailand, two thirds of paddy fields yield the organism, and 80% of children have antibodies by the time they are 4 years old. However, interpretation of these results has been complicated by

David A. B Dance

2000-01-01

57

A CLUSTER OF MELIOIDOSIS CASES FROM AN ENDEMIC REGION IS CLONAL AND IS LINKED TO THE WATER SUPPLY USING MOLECULAR TYPING OF BURKHOLDERIA PSEUDOMALLEI ISOLATES  

Microsoft Academic Search

Abstract. Nine cases of melioidosis with four deaths occurred over a 28-month period in members,of a small remote Aboriginal community,in the top end of the Northern Territory of Australia. Typing by pulsed-field gel electrophoresis showed,isolates of Burkholderia pseudomalleifrom six of the cases to be clonal and also identical to an isolate from the community water supply, but not to soil

Bart J. Currie; Mark Mayo; Nicholas M. Anstey; Phillip Donohoe; Antje Haase; David J. Kemp

58

A simple method to detect and differentiate Burkholderia pseudomallei and Burkholderia thailandensis using specific flagellin gene primers  

Microsoft Academic Search

We have previously shown that Burkholderia pseudomallei, the causative pathogen of melioidosis, may be discriminated from the closely related non-pathogenic species Burkholderia thailandensis by the presence of a 15 base pair deletion in the flagellin gene of B. thailandensis. Using specific flagellin gene primers flanking the distinctive region, PCR products of 191 and 176bp in size were detected for B.

Piengchan Sonthayanon; Piamnukul Krasao; Vannaporn Wuthiekanun; Sakol Panyim; Sumalee Tungpradabkul

2002-01-01

59

Nonrandom Distribution of Burkholderia pseudomallei Clones in Relation to Geographical Location and Virulence  

Microsoft Academic Search

Burkholderia pseudomallei is a soil-dwelling saprophyte and the causative agent of melioidosis, a life- threatening human infection. Most cases are reported from northeast Thailand and northern Australia. Using multilocus sequence typing (MLST), we have compared (i) soil and invasive isolates from northeast Thailand and (ii) invasive isolates from Thailand and Australia. A total of 266 Thai B. pseudomallei isolates were

Mongkol Vesaratchavest; Sarinna Tumapa; Nicholas P. J. Day; Vanaporn Wuthiekanun; Wirongrong Chierakul; Matthew T. G. Holden; Nicholas J. White; Bart J. Currie; Brian G. Spratt; Edward J. Feil; Sharon J. Peacock

2006-01-01

60

Biological Relevance of Colony Morphology and Phenotypic Switching by Burkholderia pseudomallei  

Microsoft Academic Search

Melioidosis is a notoriously protracted illness and is difficult to cure. We hypothesize that the causative organism, Burkholderia pseudomallei, undergoes a process of adaptation involving altered expression of surface determinants which facilitates persistence in vivo and that this is reflected by changes in colony morphology. A colony morphotyping scheme and typing algorithm were developed using clinical B. pseudomallei isolates. Morphotypes

Narisara Chantratita; Vanaporn Wuthiekanun; Khaemaporn Boonbumrung; R. Tiyawisutsri; M. Vesaratchavest; D. Limmathurotsakul; W. Chierakul; S. Wongratanacheewin; S. Pukritiyakamee; N. J. White; N. P. J. Day; S. J. Peacock

2007-01-01

61

Rapid presumptive identification of Burkholderia pseudomallei with real-time PCR assays using fluorescent hybridization probes  

Microsoft Academic Search

Burkholderia pseudomallei (the etiologic agent of melioidosis) can cause pyogenic or granulomatous lesions in almost any organ. Septicemia has a case fatality rate of >40%. Early diagnosis and appropriate antibiotic therapy are crucial for survival, but cultivation, biochemical identification, and conventional PCR of B. pseudomallei are time consuming. We established real-time PCR assays using fluorescent hybridization probes targeting the 16S

Herbert Tomaso; Tyrone L. Pitt; Olfert Landt; Sascha Al Dahouk; Holger C. Scholz; Emil C. Reisinger; Lisa D. Sprague; Ilka Rathmann; Heinrich Neubauer

2005-01-01

62

Distribution of type III secretion gene clusters in Burkholderia pseudomallei, B. thailandensis and B. mallei  

Microsoft Academic Search

Burkholderia pseudomallei, the causative agent of melioidosis, carries a cluster of genes closely related in organisation to the type III secretion (TTS) system gene clusters of the plant pathogens Ralstonia solanacearum and Xanthomonas spp. The TTS gene cluster (TTS1) is present only in B. pseudomallei and not in avirulent B. thailandensis. Adjacent to the gene cluster encoding putative secreton structural

LUCILLE RAINBOW; C. ANTHONY HART; CRAIG WINSTANLEY

63

Interaction between Burkholderia pseudomallei and Acanthamoeba Species Results in Coiling Phagocytosis, Endamebic Bacterial Survival, and Escape  

Microsoft Academic Search

Burkholderia pseudomallei causes melioidosis, a potentially fatal disease whose clinical outcomes include rapid- onset septicemia and relapsing and delayed-onset infections. Like other facultative intracellular bacterial patho- gens, B. pseudomallei is capable of survival in human phagocytic cells, but unlike mycobacteria, Listeria monocytogenes, and Salmonella serovar Typhimurium, the species has not been reported to survive as an endosymbiont in free-living amebae.

TIMOTHY J. J. INGLIS; PAUL RIGBY; TERRY A. ROBERTSON; NICHOLE S. DUTTON; MANDY HENDERSON; BARBARA J. CHANG

2000-01-01

64

Whole-Genome Sequences of 80 Environmental and Clinical Isolates of Burkholderia pseudomallei.  

PubMed

Here, we present the draft genome sequences of 80 isolates of Burkholderia pseudomallei. The isolates represent clinical cases of melioidosis and environmental isolates from regions in Australia and Papua New Guinea where B. pseudomallei is endemic. The genomes provide further context for the diversity of the pathogen. PMID:25676747

Johnson, Shannon L; Baker, Anthony L; Chain, Patrick S; Currie, Bart J; Daligault, Hajnalka E; Davenport, Karen W; Davis, Christopher B; Inglis, Timothy J J; Kaestli, Mirjam; Koren, Sergey; Mayo, Mark; Merritt, Adam J; Price, Erin P; Sarovich, Derek S; Warner, Jeffrey; Rosovitz, M J

2015-01-01

65

Molecular Characterization of Genetic Loci Required for Secretion of Exoproducts in Burkholderia pseudomallei  

Microsoft Academic Search

Previous studies have demonstrated that Burkholderia pseudomallei secretes protease, lipase, and phospho- lipase C (PLC) into the extracellular milieu, but their mechanisms of secretion and roles in pathogenesis have not been elucidated. In this study, we isolated and characterized 29 transposon mutants unable to secrete protease, lipase, and PLC. Melioidosis is an infection caused by the gram-negative ba- cillus Burkholderia

DAVID DESHAZER; PAUL J. BRETT; MARY N. BURTNICK; DONALD E. WOODS

1999-01-01

66

Strategies for Intracellular Survival of Burkholderia pseudomallei  

PubMed Central

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 Secretion System clusters, which also mediate, at least in part, the escape of bacteria from the endosome into the cytoplasm, where bacteria move by actin-based motility. The mechanism of actin-based motility is not clearly understood, but appears to differ from characterized mechanisms in other bacterial species. A small proportion of intracellular bacteria is targeted by host cell autophagy, involving direct recruitment of LC3 to endosomes rather than through uptake by canonical autophagosomes. However, the majority of bacterial cells are able to circumvent autophagy and other intracellular defense mechanisms such as the induction of inducible nitric oxide synthase, and then replicate in the cytoplasm and spread to adjacent cells via membrane fusion, resulting in the formation of multi-nucleated giant cells. A potential role for host cell ubiquitin in the autophagic response to bacterial infection has recently been proposed. PMID:22007185

Allwood, Elizabeth M.; Devenish, Rodney J.; Prescott, Mark; Adler, Ben; Boyce, John D.

2011-01-01

67

Macrophage-lymphocyte interactions mediate anti- Burkholderia pseudomallei activity  

Microsoft Academic Search

The mechanisms involved in the pathogenesis of melioidosis, caused by the intracellular bacterium Burkholderia pseudomallei, are unclear. C57BL\\/6 mice are resistant to infection, while BALB\\/c mice are highly susceptible. Previous studies have demonstrated that peritoneal exudate cell preparations enriched for macrophages are capable of effectively eliminating intracellular pathogens. In this study we present evidence showing that interaction of macrophages with

Glen C Ulett; Natkunam Ketheesan; Robert G Hirst

1998-01-01

68

NUROP Congress Paper A Second Quorum Sensing Regulon in Burkholderia pseudomallei  

Microsoft Academic Search

Burkholderia pseudomallei, a Gram-negative soil bacterium, is the causative agent of melioidosis. Quorum sensing is a mechanism responsible for the regulated expression of virulence genes in many bacterial pathogens. The first quorum sensing regulon in B. pseudomallei, Ai s\\/Air, was recently identified in our laboratory. The report describes the identification of a second quorum sensing regulon, RhlI\\/RhlR, in B. pseudomallei

69

Development of Burkholderia mallei and pseudomallei vaccines  

PubMed Central

Burkholderia mallei and Burkholderia pseudomallei are Gram-negative bacteria that cause glanders and melioidosis, respectively. Inhalational infection with either organism can result in severe and rapidly fatal pneumonia. Inoculation by the oral and cutaneous routes can also produce infection. Chronic infection may develop after recovery from acute infection with both agents, and control of infection with antibiotics requires prolonged treatment. Symptoms for both meliodosis and glanders are non-specific, making diagnosis difficult. B. pseudomallei can be located in the environment, but in the host, B. mallei and B. psedomallei are intracellular organisms, and infection results in similar immune responses to both agents. Effective early innate immune responses are critical to controlling the early phase of the infection. Innate immune signaling molecules such as TLR, NOD, MyD88, and pro-inflammatory cytokines such as IFN-? and TNF-? play key roles in regulating control of infection. Neutrophils and monocytes are critical cells in the early infection for both microorganisms. Both monocytes and macrophages are necessary for limiting dissemination of B. pseudomallei. In contrast, the role of adaptive immune responses in controlling Burkholderia infection is less well understood. However, T cell responses are critical for vaccine protection from Burkholderia infection. At present, effective vaccines for prevention of glanders or meliodosis have not been developed, although recently development of Burkholderia vaccines has received renewed attention. This review will summarize current and past approaches to develop B. mallei and B. pseudomalllei vaccines, with emphasis on immune mechanisms of protection and the challenges facing the field. At present, immunization with live attenuated bacteria provides the most effective and durable immunity, and it is important therefore to understand the immune correlates of protection induced by live attenuated vaccines. Subunit vaccines have typically provided less robust immunity, but are safer to administer to a wider variety of people, including immune compromised individuals because they do not reactivate or cause disease. The challenges facing B. mallei and B. pseudomalllei vaccine development include identification of broadly protective antigens, design of efficient vaccine delivery and adjuvant systems, and a better understanding of the correlates of protection from both acute and chronic infection. PMID:23508691

Silva, Ediane B.; Dow, Steven W.

2013-01-01

70

Molecular phylogeny of Burkholderia pseudomallei  

Microsoft Academic Search

In terms of population structure, the species Burkholderia pseudomallei contains both clonal and non-clonal elements. By indexing variation in rRNA loci using the restriction endonuclease BamHI, we found that two ribotypes (types 1 and 3) are predominant in nature. Ribotype 3 is prevalent in Asian countries while ribotype 1 is more widespread. Some disease association was suggested for 4 ribotypes

Tyrone L Pitt; Suwanna Trakulsomboon; David A. B Dance

2000-01-01

71

Pleuropulmonary melioidosis with osteomyelitis rib  

PubMed Central

Melioidosis is a multiorgan infectious disease caused by Burkholderia pseudomallei. Few cases have been reported from south India. This is a case report of pleuropulmonary melioidosis with rib osteomyelitis.

Neliyathodi, Suhail; Thazhathethil, Abdul Nazar; Pallivalappil, Lisha; Balakrishnan, Deepu

2015-01-01

72

Type III secretion system cluster 3 is required for maximal virulence of Burkholderia pseudomallei in a hamster infection model  

Microsoft Academic Search

Burkholderia pseudomallei, the etiological agent of melioidosis, is an animal pathogen capable of inducing a highly fatal septicemia. B. pseudomallei possesses three type III secretion system (TTSS) clusters, two of which (TTSS1 and TTSS2) are homologous to the TTSS of the plant pathogen Ralstonia solanacearum, and one (TTSS3) is homologous to the Salmonella SPI-1 mammalian pathogenicity island. We have demonstrated

Jonathan Warawa; Donald E. Woods

2005-01-01

73

The Burkholderia pseudomallei RpoE (AlgU) operon is involved in environmental stress tolerance and biofilm formation  

Microsoft Academic Search

Burkholderia pseudomallei, the causative agent of melioidosis, can be isolated from soil and water. To persist, adapt and survive within and outside their human host, bacteria rely on regulatory mechanisms that allow them to respond rapidly to stressful situations. We have examined the possible role of B. pseudomallei alternative sigma factor ?E (RpoE) in the stress response and found that

Sunee Korbsrisate; Muthita Vanaporn; Phansupa Kerdsuk; Wannapa Kespichayawattana; Paiboon Vattanaviboon; Pornpimon Kiatpapan; Ganjana Lertmemongkolchai

2005-01-01

74

Detection of Bacterial Virulence Genes by Subtractive Hybridization: Identification of Capsular Polysaccharide of Burkholderia pseudomallei as a Major Virulence Determinant  

Microsoft Academic Search

Burkholderia pseudomallei, the etiologic agent of melioidosis, is responsible for a broad spectrum of illnesses in humans and animals particularly in Southeast Asia and northern Australia, where it is endemic. Burkhold- eria thailandensis is a nonpathogenic environmental organism closely related to B. pseudomallei. Subtractive hybridization was carried out between these two species to identify genes encoding virulence determinants in B.

SHAUNA L. RECKSEIDLER; DAVID DESHAZER; PAMELA A. SOKOL; DONALD E. WOODS

2001-01-01

75

Backbone and side chain 1H, 13C, and 15N NMR assignments for the organic hydroperoxide resistance protein (Ohr) from Burkholderia pseudomallei  

PubMed Central

Burkholderia pseudomallei is a NIAID Category B microorganism responsible for melioidosis. Here we report backbone and side chain NMR assignments for the 139-residue, homodimeric, organic hydroperoxide resistance protein (Ohr) from this organism. PMID:19888681

Buchko, Garry W.; Hewitt, Stephen N.; Napuli, Alberto J.; van Voorhis, Wesley C.; Myler, Peter J.

2009-01-01

76

Induction of multiple chemokine and colony-stimulating factor genes in experimental Burkholderia pseudomallei infection  

Microsoft Academic Search

Melioidosis is a disease of the tropics caused by the facultative intracellular bacterium Burkholderia pseudomallei. In human infection, increased levels of IFN-? in addition to the chemokines interferon-?-inducible protein 10 (IP-10) and monocyte interferon-?-inducible protein (Mig) have been demonstrated. However, the role of these and other chemokines in the pathogenesis of melioidosis remains unknown. Using BALB\\/c and C57BL\\/6 mice as

Jodie L Barnes; Glen C Ulett; Natkunam Ketheesan; Timothy Clair; Phillip M Summers; Robert G Hirst

2001-01-01

77

Novel Selective Medium for Isolation of Burkholderia pseudomallei  

Microsoft Academic Search

Isolation of Burkholderia pseudomallei currently relies on the use of Ashdown's selective agar (ASA). We designed a new selective agar (Burkholderia pseudomallei selective agar (BPSA)) to improve recovery of the more easily inhibited strains of B. pseudomallei. B. pseudomallei, Burkholderia cepacia, and Pseudomonas aerugi- nosa were used to determine the selectivity and sensitivity of BPSA. BPSA was more inhibitory to

K. Howard; T. J. J. Inglis

2003-01-01

78

Functional Characterization of Burkholderia pseudomallei Trimeric Autotransporters  

PubMed Central

Burkholderia pseudomallei is a tier 1 select agent and the causative agent of melioidosis, a severe and often fatal disease with symptoms ranging from acute pneumonia and septic shock to a chronic infection characterized by abscess formation in the lungs, liver, and spleen. Autotransporters (ATs) are exoproteins belonging to the type V secretion system family, with many playing roles in pathogenesis. The genome of B. pseudomallei strain 1026b encodes nine putative trimeric AT proteins, of which only four have been described. Using a bioinformatic approach, we annotated putative domains within each trimeric AT protein, excluding the well-studied BimA protein, and found short repeated sequences unique to Burkholderia species, as well as an unexpectedly large proportion of ATs with extended signal peptide regions (ESPRs). To characterize the role of trimeric ATs in pathogenesis, we constructed disruption or deletion mutations in each of eight AT-encoding genes and evaluated the resulting strains for adherence to, invasion of, and plaque formation in A549 cells. The majority of the ATs (and/or the proteins encoded downstream) contributed to adherence to and efficient invasion of A549 cells. Using a BALB/c mouse model of infection, we determined the contributions of each AT to bacterial burdens in the lungs, liver, and spleen. At 48 h postinoculation, only one strain, Bp340::pDbpaC, demonstrated a defect in dissemination and/or survival in the liver, indicating that BpaC is required for wild-type virulence in this model. PMID:23716608

Campos, Cristine G.; Byrd, Matthew S.

2013-01-01

79

BpeAB-OprB, a Multidrug Efflux Pump in Burkholderia pseudomallei  

Microsoft Academic Search

Burkholderia pseudomallei, the causative agent of melioidosis, is intrinsically resistant to a wide range of antimicrobial agents, including -lactams, aminoglycosides, macrolides, and polymyxins. An operon, bpeR- bpeA-bpeB-oprB, which encodes a putative repressor, a membrane fusion protein, an inner membrane protein, and an outer membrane protein, respectively, of a multidrug efflux pump of the resistance-nodulation-division family was identified in B. pseudomallei.

Y. Y. Chan; T. M. C. Tan; Y. M. Ong; K. L. Chua

2004-01-01

80

Characterisation of an acapsular mutant of Burkholderia pseudomallei identified by signature tagged mutagenesis  

Microsoft Academic Search

A Burkholderia pseudomallei mutant which was attenuated in a mouse model of melioidosis was identified by a signature tagged mutagenesis approach. The transposon was shown to be inserted into a gene within the capsular biosynthetic operon. Compared with the wild-type bacteria this mutant demonstrated a 105-fold increase in the median lethal dose in a mouse model and it did not

TIMOTHY ATKINS; RICHARD PRIOR; KERRI MACK; PAUL RUSSELL; MICHELLE NELSON; JILL ELLIS; PETRA C. F. OYSTON; GORDON DOUGAN; RICHARD W. TITBALL

2002-01-01

81

Sequencing and characterization of a novel serine metalloprotease from Burkholderia pseudomallei  

Microsoft Academic Search

Burkholderia pseudomallei, a Gram-negative bacterium is found in the soil and water, mainly in Southeast Asia and Northern Australia. It is responsible for melioidosis in human and animals. The bacteria produce several potential virulent factors such as extracellular protease, hemolysin, lipase and lecithinase. The isolation of virulence genes and the study of their functions will contribute to our understanding of

May-Ann Lee; Yichun Liu

2000-01-01

82

Purification and characterization of an exopolysaccharide of Burkholderia (Pseudomonas) pseudomallei.  

PubMed Central

Burkholderia pseudomallei (basonym Pseudomonas pseudomallei) is the causative organism of melioidosis, a disease which is recognized as a major public health problem primarily in Southeast Asia and Northern Australia. In this paper, we report on the identification, purification, and characterization of a species-specific exopolysaccharide of B. pseudomallei. After immunization of mice with a B. pseudomallei strain exhibiting mucoid growth characteristics, we isolated an immunoglobulin G1 monoclonal antibody (MAb) (3015) with specificity for a carbohydrate structure as determined by immunoblotting following sodium dodecyl sulfatepolyacrylamide gel electrophoresis. Electron microscopy studies with MAb 3015 revealed reactivity with an exopolysaccharide with a capsule-like appearance in the immunizing strain. All of the mucoid and nonmucoid B. pseudomallei strains tested from geographically different tropical regions were recognized by MAb 3015 in an enzyme-linked immunosorbent assay or immunoblot, indicating that the exopolysaccharide is constitutively expressed among this species. Intensive testing for cross-reactivity including members of all the Pseudomonas rRNA groups showed no cross-reactivity except in the case of the closely related species Burkholderia mallei. A protocol for purification of the exopolysaccharide which is based principally on mechanical separation from the cell surface followed by repetitive ethanol precipitation steps and finally affinity chromatography using MAb 3015 was established. The exopolysaccharide yielded was of high purity. Gel permeation chromatography was performed, and the molecular mass was estimated to be > 150 kDa. Sera from patients with melioidosis were strongly reactive with the purified exopolysaccharide, indicating its in vivo expression and immunogenicity in natural infection. The diagnostic value of the exopolysaccharide and its role in the pathogenesis of disease must still be determined. PMID:7558305

Steinmetz, I; Rohde, M; Brenneke, B

1995-01-01

83

EPIDEMIOLOGY OF BURKHOLDERIA PSEUDOMALLEI IN THAILAND  

Microsoft Academic Search

The distribution of Burkholderia pseudomalleiin soil collected from four regions of Thailand and the frequency of B. pseudomallei infections in patients attending government hospitals throughout Thailand in 1997 were surveyed. A total of 3,585 soil samples collected from 896 sites in four regions of Thailand were cultured for B. pseudomallei using selective enrichment broth and modified Ashdown's agar. The organism

VARAPORN VUDDHAKUL; PRASIT THARAVICHITKUL; NARISORN NA-NGAM; SIROJ JITSURONG; BANYONG KUNTHAWA; PITAK NOIMAY; PANPETH NOIMAY; ANUCHIT BINLA; VISANU THAMLIKITKUL

1999-01-01

84

Systematic Review and Consensus Guidelines for Environmental Sampling of Burkholderia pseudomallei  

PubMed Central

Background Burkholderia pseudomallei, a Tier 1 Select Agent and the cause of melioidosis, is a Gram-negative bacillus present in the environment in many tropical countries. Defining the global pattern of B. pseudomallei distribution underpins efforts to prevent infection, and is dependent upon robust environmental sampling methodology. Our objective was to review the literature on the detection of environmental B. pseudomallei, update the risk map for melioidosis, and propose international consensus guidelines for soil sampling. Methods/Principal Findings An international working party (Detection of Environmental Burkholderia pseudomallei Working Party (DEBWorP)) was formed during the VIth World Melioidosis Congress in 2010. PubMed (January 1912 to December 2011) was searched using the following MeSH terms: pseudomallei or melioidosis. Bibliographies were hand-searched for secondary references. The reported geographical distribution of B. pseudomallei in the environment was mapped and categorized as definite, probable, or possible. The methodology used for detecting environmental B. pseudomallei was extracted and collated. We found that global coverage was patchy, with a lack of studies in many areas where melioidosis is suspected to occur. The sampling strategies and bacterial identification methods used were highly variable, and not all were robust. We developed consensus guidelines with the goals of reducing the probability of false-negative results, and the provision of affordable and ‘low-tech’ methodology that is applicable in both developed and developing countries. Conclusions/Significance The proposed consensus guidelines provide the basis for the development of an accurate and comprehensive global map of environmental B. pseudomallei. PMID:23556010

Limmathurotsakul, Direk; Dance, David A. B.; Wuthiekanun, Vanaporn; Kaestli, Mirjam; Mayo, Mark; Warner, Jeffrey; Wagner, David M.; Tuanyok, Apichai; Wertheim, Heiman; Yoke Cheng, Tan; Mukhopadhyay, Chiranjay; Puthucheary, Savithiri; Day, Nicholas P. J.; Steinmetz, Ivo; Currie, Bart J.; Peacock, Sharon J.

2013-01-01

85

Nitric oxide-dependent killing of aerobic, anaerobic and persistent Burkholderia pseudomallei  

PubMed Central

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 the drugs hydroxyurea, spermine NONOate and DETA NONOate that release nitric oxide (NO). Our investigations indicate that B. pseudomallei are killed by NO in a concentration and time-dependent fashion. The cytoxicity of this diatomic radical against B. pseudomallei depends on both the culture medium and growth phase of the bacteria. Rapidly growing, but not stationary phase, B. pseudomallei are readily killed upon exposure to the NO donor spermine NONOate. NO also has excellent antimicrobial activity against anaerobic B. pseudomallei. In addition, persistent bacteria highly resistant to most conventional antibiotics are remarkably susceptible to NO. Sublethal concentrations of NO inhibited the enzymatic activity of [4Fe-4S]-cofactored aconitase of aerobic and anaerobic B. pseudomallei. The strong anti-B. pseudomallei activity of NO described herein merits further studies on the application of NO-based antibiotics for the treatment of melioidosis. PMID:22521523

Jones-Carson, Jessica; Laughlin, James R.; Stewart, Amanda L.; Voskuil, Martin I.; Vázquez-Torres, Andrés

2012-01-01

86

Bioluminescent Diagnostic Imaging to Characterize Altered Respiratory Tract Colonization by the Burkholderia Pseudomallei Capsule Mutant  

PubMed Central

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. Hairless outbred SKH1 mice were used to enhance the ability to monitor B. pseudomallei respiratory disease, and were found to be similarly susceptible to respiratory melioidosis as BALB/c mice. This represents the first demonstration of in vivo diagnostic imaging of pulmonary melioidosis permitting the detection of B. pseudomallei less than 24?h post-infection. Diagnostic imaging of pulmonary melioidosis revealed distinct temporal patterns of bacterial colonization unique to both BALB/c and SKH1 mice. Validation of these model systems included the use of the previously characterized capsule mutant, which was found to colonize the upper respiratory tract at significantly higher levels than the wild type strain. These model systems allow for high resolution detection of bacterial pulmonary disease which will facilitate studies of therapeutics and basic science evaluation of melioidosis. PMID:21720539

Warawa, Jonathan M.; Long, Dan; Rosenke, Rebecca; Gardner, Don; Gherardini, Frank C.

2011-01-01

87

Polar Lipids of Burkholderia pseudomallei Induce Different Host Immune Responses  

PubMed Central

Melioidosis is a disease in tropical and subtropical regions of the world that is caused by Burkholderia pseudomallei. In endemic regions the disease occurs primarily in humans and goats. In the present study, we used the goat as a model to dissect the polar lipids of B. pseudomallei to identify lipid molecules that could be used for adjuvants/vaccines or as diagnostic tools. We showed that the lipidome of B. pseudomallei and its fractions contain several polar lipids with the capacity to elicit different immune responses in goats, namely rhamnolipids and ornithine lipids which induced IFN-?, whereas phospholipids and an undefined polar lipid induced strong IL-10 secretion in CD4+ T cells. Autologous T cells co-cultured with caprine dendritic cells (cDCs) and polar lipids of B. pseudomallei proliferated and up-regulated the expression of CD25 (IL-2 receptor) molecules. Furthermore, we demonstrated that polar lipids were able to up-regulate CD1w2 antigen expression in cDCs derived from peripheral blood monocytes. Interestingly, the same polar lipids had only little effect on the expression of MHC class II DR antigens in the same caprine dendritic cells. Finally, antibody blocking of the CD1w2 molecules on cDCs resulted in decreased expression for IFN-? by CD4+ T cells. Altogether, these results showed that polar lipids of B. pseudomallei are recognized by the caprine immune system and that their recognition is primarily mediated by the CD1 antigen cluster. PMID:24260378

Gonzalez-Juarrero, Mercedes; Mima, Naoko; Trunck, Lily A.; Schweizer, Herbert P.; Bowen, Richard A.; Dascher, Kyle; Mwangi, Waithaka; Eckstein, Torsten M.

2013-01-01

88

Interrogation of the Burkholderia pseudomallei Genome to Address Differential Virulence among Isolates  

PubMed Central

Infection by the Gram-negative pathogen Burkholderia pseudomallei results in the disease melioidosis, acquired from the environment in parts of southeast Asia and northern Australia. Clinical symptoms of melioidosis range from acute (fever, pneumonia, septicemia, and localized infection) to chronic (abscesses in various organs and tissues, most commonly occurring in the lungs, liver, spleen, kidney, prostate and skeletal muscle), and persistent infections in humans are difficult to cure. Understanding the basic biology and genomics of B. pseudomallei is imperative for the development of new vaccines and therapeutic interventions. This formidable task is becoming more tractable due to the increasing number of B. pseudomallei genomes that are being sequenced and compared. Here, we compared three B. pseudomallei genomes, from strains MSHR668, K96243 and 1106a, to identify features that might explain why MSHR668 is more virulent than K96243 and 1106a in a mouse model of B. pseudomallei infection. Our analyses focused on metabolic, virulence and regulatory genes that were present in MSHR668 but absent from both K96243 and 1106a. We also noted features present in K96243 and 1106a but absent from MSHR668, and identified genomic differences that may contribute to variations in virulence noted among the three B. pseudomallei isolates. While this work contributes to our understanding of B. pseudomallei genomics, more detailed experiments are necessary to characterize the relevance of specific genomic features to B. pseudomallei metabolism and virulence. Functional analyses of metabolic networks, virulence and regulation shows promise for examining the effects of B. pseudomallei on host cell metabolism and will lay a foundation for future prediction of the virulence of emerging strains. Continued emphasis in this area will be critical for protection against melioidosis, as a better understanding of what constitutes a fully virulent Burkholderia isolate may provide for better diagnostic and medical countermeasure strategies. PMID:25536074

Challacombe, Jean F.; Stubben, Chris J.; Klimko, Christopher P.; Welkos, Susan L.; Kern, Steven J.; Bozue, Joel A.; Worsham, Patricia L.; Cote, Christopher K.; Wolfe, Daniel N.

2014-01-01

89

Interrogation of the Burkholderia pseudomallei Genome to Address Differential Virulence among Isolates.  

PubMed

Infection by the Gram-negative pathogen Burkholderia pseudomallei results in the disease melioidosis, acquired from the environment in parts of southeast Asia and northern Australia. Clinical symptoms of melioidosis range from acute (fever, pneumonia, septicemia, and localized infection) to chronic (abscesses in various organs and tissues, most commonly occurring in the lungs, liver, spleen, kidney, prostate and skeletal muscle), and persistent infections in humans are difficult to cure. Understanding the basic biology and genomics of B. pseudomallei is imperative for the development of new vaccines and therapeutic interventions. This formidable task is becoming more tractable due to the increasing number of B. pseudomallei genomes that are being sequenced and compared. Here, we compared three B. pseudomallei genomes, from strains MSHR668, K96243 and 1106a, to identify features that might explain why MSHR668 is more virulent than K96243 and 1106a in a mouse model of B. pseudomallei infection. Our analyses focused on metabolic, virulence and regulatory genes that were present in MSHR668 but absent from both K96243 and 1106a. We also noted features present in K96243 and 1106a but absent from MSHR668, and identified genomic differences that may contribute to variations in virulence noted among the three B. pseudomallei isolates. While this work contributes to our understanding of B. pseudomallei genomics, more detailed experiments are necessary to characterize the relevance of specific genomic features to B. pseudomallei metabolism and virulence. Functional analyses of metabolic networks, virulence and regulation shows promise for examining the effects of B. pseudomallei on host cell metabolism and will lay a foundation for future prediction of the virulence of emerging strains. Continued emphasis in this area will be critical for protection against melioidosis, as a better understanding of what constitutes a fully virulent Burkholderia isolate may provide for better diagnostic and medical countermeasure strategies. PMID:25536074

Challacombe, Jean F; Stubben, Chris J; Klimko, Christopher P; Welkos, Susan L; Kern, Steven J; Bozue, Joel A; Worsham, Patricia L; Cote, Christopher K; Wolfe, Daniel N

2014-01-01

90

Burkholderia pseudomallei isolates from Sarawak, Malaysian Borneo, are predominantly susceptible to aminoglycosides and macrolides.  

PubMed

Melioidosis is a potentially fatal disease caused by the saprophytic bacterium Burkholderia pseudomallei. Resistance to gentamicin is generally a hallmark of B. pseudomallei, and gentamicin is a selective agent in media used for diagnosis of melioidosis. In this study, we determined the prevalence and mechanism of gentamicin susceptibility found in B. pseudomallei isolates from Sarawak, Malaysian Borneo. We performed multilocus sequence typing and antibiotic susceptibility testing on 44 B. pseudomallei clinical isolates from melioidosis patients in Sarawak district hospitals. Whole-genome sequencing was used to identify the mechanism of gentamicin susceptibility. A novel allelic-specific PCR was designed to differentiate gentamicin-sensitive isolates from wild-type B. pseudomallei. A reversion assay was performed to confirm the involvement of this mechanism in gentamicin susceptibility. A substantial proportion (86%) of B. pseudomallei clinical isolates in Sarawak, Malaysian Borneo, were found to be susceptible to the aminoglycoside gentamicin, a rare occurrence in other regions where B. pseudomallei is endemic. Gentamicin sensitivity was restricted to genetically related strains belonging to sequence type 881 or its single-locus variant, sequence type 997. Whole-genome sequencing identified a novel nonsynonymous mutation within amrB, encoding an essential component of the AmrAB-OprA multidrug efflux pump. We confirmed the role of this mutation in conferring aminoglycoside and macrolide sensitivity by reversion of this mutation to the wild-type sequence. Our study demonstrates that alternative B. pseudomallei selective media without gentamicin are needed for accurate melioidosis laboratory diagnosis in Sarawak. This finding may also have implications for environmental sampling of other locations to test for B. pseudomallei endemicity. PMID:24145517

Podin, Yuwana; Sarovich, Derek S; Price, Erin P; Kaestli, Mirjam; Mayo, Mark; Hii, KingChing; Ngian, Hieung; Wong, SeeChang; Wong, IngTien; Wong, JinShyan; Mohan, Anand; Ooi, MongHow; Fam, TemLom; Wong, Jack; Tuanyok, Apichai; Keim, Paul; Giffard, Philip M; Currie, Bart J

2014-01-01

91

Burkholderia pseudomallei Isolates from Sarawak, Malaysian Borneo, Are Predominantly Susceptible to Aminoglycosides and Macrolides  

PubMed Central

Melioidosis is a potentially fatal disease caused by the saprophytic bacterium Burkholderia pseudomallei. Resistance to gentamicin is generally a hallmark of B. pseudomallei, and gentamicin is a selective agent in media used for diagnosis of melioidosis. In this study, we determined the prevalence and mechanism of gentamicin susceptibility found in B. pseudomallei isolates from Sarawak, Malaysian Borneo. We performed multilocus sequence typing and antibiotic susceptibility testing on 44 B. pseudomallei clinical isolates from melioidosis patients in Sarawak district hospitals. Whole-genome sequencing was used to identify the mechanism of gentamicin susceptibility. A novel allelic-specific PCR was designed to differentiate gentamicin-sensitive isolates from wild-type B. pseudomallei. A reversion assay was performed to confirm the involvement of this mechanism in gentamicin susceptibility. A substantial proportion (86%) of B. pseudomallei clinical isolates in Sarawak, Malaysian Borneo, were found to be susceptible to the aminoglycoside gentamicin, a rare occurrence in other regions where B. pseudomallei is endemic. Gentamicin sensitivity was restricted to genetically related strains belonging to sequence type 881 or its single-locus variant, sequence type 997. Whole-genome sequencing identified a novel nonsynonymous mutation within amrB, encoding an essential component of the AmrAB-OprA multidrug efflux pump. We confirmed the role of this mutation in conferring aminoglycoside and macrolide sensitivity by reversion of this mutation to the wild-type sequence. Our study demonstrates that alternative B. pseudomallei selective media without gentamicin are needed for accurate melioidosis laboratory diagnosis in Sarawak. This finding may also have implications for environmental sampling of other locations to test for B. pseudomallei endemicity. PMID:24145517

Podin, Yuwana; Sarovich, Derek S.; Price, Erin P.; Kaestli, Mirjam; Mayo, Mark; Hii, KingChing; Ngian, HieUng; Wong, SeeChang; Wong, IngTien; Wong, JinShyan; Mohan, Anand; Ooi, MongHow; Fam, TemLom; Wong, Jack; Tuanyok, Apichai; Keim, Paul; Giffard, Philip M.

2014-01-01

92

The toxin/immunity network of Burkholderia pseudomallei contact-dependent growth inhibition (CDI) systems.  

PubMed

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 ?-proteobacteria. CDI systems from Escherichia coli and Dickeya dadantii play significant roles in bacterial competition, suggesting these systems may also contribute to the competitive fitness of B.?pseudomallei. Here, we identify 10 distinct CDI systems in B.?pseudomallei based on polymorphisms within the cdiA-CT/cdiI coding regions, which are predicted to encode CdiA-CT/CdiI toxin/immunity protein pairs. Biochemical analysis of three B.?pseudomallei CdiA-CTs revealed that each protein possesses a distinct tRNase activity capable of inhibiting cell growth. These toxin activities are blocked by cognate CdiI immunity proteins, which specifically bind the CdiA-CT and protect cells from growth inhibition. Using Burkholderia thailandensis E264 as a model, we show that a CDI system from B.?pseudomallei 1026b mediates CDI and is capable of delivering CdiA-CT toxins derived from other B.?pseudomallei strains. These results demonstrate that Burkholderia species contain functional CDI systems, which may confer a competitive advantage to these bacteria. PMID:22435733

Nikolakakis, Kiel; Amber, Saba; Wilbur, J Scott; Diner, Elie J; Aoki, Stephanie K; Poole, Stephen J; Tuanyok, Apichai; Keim, Paul S; Peacock, Sharon; Hayes, Christopher S; Low, David A

2012-05-01

93

The Capsular Polysaccharide of Burkholderia pseudomallei Contributes to Survival in Serum by Reducing Complement Factor C3b Deposition  

Microsoft Academic Search

Burkholderia pseudomallei produces an extracellular polysaccharide capsule -3)-2-O-acetyl-6-deoxy--D- manno-heptopyranose-(1- which has been shown to be an essential virulence determinant. The addition of purified capsule was shown to increase the virulence of a capsule mutant strain in the Syrian hamster model of acute melioidosis. An increase in the number of wild-type B. pseudomallei cells in the blood was seen by 48

Shauna L. Reckseidler-Zenteno; Rebekah DeVinney; Donald E. Woods

2005-01-01

94

Evidence for the presence in Burkholderia pseudomallei of a type III secretion system-associated gene cluster  

Microsoft Academic Search

Burkholderia pseudomallei, the causative agent of melioidosis, contains a cluster of putative genes homologous to those encoding HpaP, HrcQ, HrcR, HrcS and HrpV in the plant pathogen Ralstonia solanacearum. In R. solanacearum, these genes form part of a type I11 secretion-associated pathogenicity island. The order of the genes in B. pseudomallei is directly equivalent to that found in R. solanacearum.

C. WINSTANLEY; B. A. HALES; C. A. HART

1999-01-01

95

Use of 16S rRNA Gene Sequencing for Rapid Identification and Differentiation of Burkholderia pseudomallei and B. mallei  

Microsoft Academic Search

Burkholderia pseudomallei and B. mallei, the causative agents of melioidosis and glanders, respectively, are designated category B biothreat agents. Current methods for identifying these organisms rely on their phe- notypic characteristics and an extensive set of biochemical reactions. We evaluated the use of 16S rRNA gene sequencing to rapidly identify these two species and differentiate them from each other as

Jay E. Gee; Claudio T. Sacchi; Mindy B. Glass; Barun K. De; Robbin S. Weyant; Paul N. Levett; Anne M. Whitney; Alex R. Hoffmaster; Tanja Popovic

2003-01-01

96

Obligatory Role of Gamma Interferon for Host Survival in a Murine Model of Infection with Burkholderia pseudomallei  

Microsoft Academic Search

Burkholderia pseudomallei, the causative agent of melioidosis, is a gram-negative bacterium capable of causing either acute lethal sepsis or chronic but eventually fatal disease in infected individuals. However, despite the clinical importance of this infection in areas where it is endemic, there is essentially no information on the mechanisms of protective immunity to the bacterium. We describe here a murine

P. SANTANIRAND; V. S. HARLEY; D. A. B. DANCE; B. S. DRASAR; G. J. BANCROFT

1999-01-01

97

Burkholderia pseudomallei Induces Cell Fusion and Actin-Associated Membrane Protrusion: a Possible Mechanism for Cell-to-Cell Spreading  

Microsoft Academic Search

Burkholderia pseudomallei, a facultative intracellular bacterium, is the causative agent of a broad spectrum of diseases collectively known as melioidosis. Its ability to survive inside phagocytic and nonphagocytic cells and to induce multinucleated giant cell (MNGC) formation has been demonstrated. This study was designed to assess a possible mechanism(s) leading to this cellular change, using virulent and nonvirulent strains of

W. Kespichayawattana; S. Rattanachetkul; T. Wanun; P. Utaisincharoen; S. Sirisinha

2000-01-01

98

Lipopolysaccharide from Nonvirulent Ara1 Burkholderia pseudomallei Isolates Is Immunologically Indistinguishable from Lipopolysaccharide from Virulent Ara2 Clinical Isolates  

Microsoft Academic Search

Different lines of evidence suggest that a discrepancy between the distribution of Burkholderia (Pseudomonas) pseudomallei in the environment and the distribution of the disease melioidosis is attributable, at least in part, to phenotypic differences between clinical and some environmental isolates. Two antigenically and biochemi- cally distinct biotypes have been described, only one of which is virulent. In this study, lipopolysaccharides

NARISARA ANUNTAGOOL; PAKAMAS INTACHOTE; VANAPORN WUTHIEKANUN; NICHOLAS J. WHITE; STITAYA SIRISINHA

99

Passive protection against Burkholderia pseudomallei infection in mice by monoclonal antibodies against capsular polysaccharide, lipopolysaccharide or proteins  

Microsoft Academic Search

Burkholderia pseudomallei, the aetiological agent of melioidosis, is endemic in south-east Asia and northern Australia, where it is an important cause of human disease. There is no vaccine available and antibiotic therapy is associated with high relapse rates. A panel of seven monoclonal antibodies (MAbs) that recognise capsular polysaccharide, lipopolysaccharide or proteins was produced and their ability to protect mice

S. M. JONES; J. F. ELLIS; P. RUSSELL; K. F. GRIFFIN; P. C. F. OYSTON

100

Specificity and Functional Activity of Anti-Burkholderia pseudomallei Polysaccharide Antibodies  

Microsoft Academic Search

The lipopolysaccharide (LPS) of Burkholderia pseudomallei, the causative agent of melioidosis, consists of two O-antigenic polysaccharides designated O-PS I and O-PS II. In this study, the O-PS specificity and functional activity of a protective polyclonal antiserum and an immunoglobulin M (IgM) monoclonal antibody were determined. The polyclonal antiserum recognized both O-PS I and O-PS II, while the monoclonal antibody was

MAY HO; TINEKE SCHOLLAARDT; MICHAEL D. SMITH; MALCOLM B. PERRY; PAUL J. BRETT; WIPADA CHAOWAGUL; LARRY E. BRYAN; Ubol Ratchatani

1997-01-01

101

groEL Encodes a Highly Antigenic Protein in Burkholderia pseudomallei  

Microsoft Academic Search

No recombinant protein is available for serodiagnosis of melioidosis. In this study, we report the cloning of the groEL gene, which encodes an immunogenic protein of Burkholderia pseudomallei. Bidirectional DNA sequencing of groEL revealed that the gene contained a single open reading frame encoding 546 amino acid residues with a predicted molecular mass of 57.1 kDa. Basic Local Alignment Search

PATRICK C. Y. WOO; PATRICIA K. L. LEUNG; SAMSON S. Y. WONG; PAK-LEUNG HO; KWOK-YUNG YUEN

2001-01-01

102

Burkholderia pseudomallei Misidentified by Automated System  

PubMed Central

After returning from Thailand, a 35-year-old man from Switzerland was hospitalized with an abscess of the head. Material cultured from the abscess and adjacent bone grew a gram-negative rod, which was misidentified by an automated microbiology system as Burkholderia cepacia. The organism was eventually identified by molecular methods as B. pseudomallei. PMID:19891868

Weissert, Christoph; Dollenmaier, Günter; Rafeiner, Philippe; Riehm, Julia

2009-01-01

103

The chemical arsenal of Burkholderia pseudomallei is essential for pathogenicity.  

PubMed

Increasing evidence has shown that small-molecule chemistry in microbes (i.e., secondary metabolism) can modulate the microbe-host response in infection and pathogenicity. The bacterial disease melioidosis is conferred by the highly virulent, antibiotic-resistant pathogen Burkholderia pseudomallei (BP). Whereas some macromolecular structures have been shown to influence BP virulence (e.g., secretion systems, cellular capsule, pili), the role of the large cryptic secondary metabolome encoded within its genome has been largely unexplored for its importance to virulence. Herein we demonstrate that BP-encoded small-molecule biosynthesis is indispensible for in vivo BP pathogenicity. Promoter exchange experiments were used to induce high-level molecule production from two gene clusters (MPN and SYR) found to be essential for in vivo virulence. NMR structural characterization of these metabolites identified a new class of lipopeptide biosurfactants/biofilm modulators (the malleipeptins) and syrbactin-type proteasome inhibitors, both of which represent overlooked small-molecule virulence factors for BP. Disruption of Burkholderia virulence by inhibiting the biosynthesis of these small-molecule biosynthetic pathways may prove to be an effective strategy for developing novel melioidosis-specific therapeutics. PMID:24884988

Biggins, John B; Kang, Hahk-Soo; Ternei, Melinda A; DeShazer, David; Brady, Sean F

2014-07-01

104

Fatal Burkholderia pseudomallei infection initially reported as a Bacillus species, Ohio, 2013.  

PubMed

A fatal case of melioidosis was diagnosed in Ohio one month after culture results were initially reported as a Bacillus species. To identify a source of infection and assess risk in patient contacts, we abstracted patient charts; interviewed physicians and contacts; genetically characterized the isolate; performed a Burkholderia pseudomallei antibody indirect hemagglutination assay on household contacts and pets to assess seropositivity; and collected household plant, soil, liquid, and insect samples for culturing and real-time polymerase chain reaction testing. Family members and pets tested were seronegative for B. pseudomallei. Environmental samples were negative by real-time polymerase chain reaction and culture. Although the patient never traveled internationally, the isolate genotype was consistent with an isolate that originated in Southeast Asia. This investigation identified the fifth reported locally acquired non-laboratory melioidosis case in the contiguous United States. Physicians and laboratories should be aware of this potentially emerging disease and refer positive cultures to a Laboratory Response Network laboratory. PMID:25092821

Doker, Thomas J; Quinn, Celia L; Salehi, Ellen D; Sherwood, Joshua J; Benoit, Tina J; Glass Elrod, Mindy; Gee, Jay E; Shadomy, Sean V; Bower, William A; Hoffmaster, Alex R; Walke, Henry T; Blaney, David D; DiOrio, Mary S

2014-10-01

105

A Burkholderia pseudomallei outer membrane vesicle vaccine provides protection against lethal sepsis.  

PubMed

The environmental Gram-negative encapsulated bacillus Burkholderia pseudomallei is the causative agent of melioidosis, a disease associated with high morbidity and mortality rates in areas of Southeast Asia and northern Australia in which the disease is endemic. B. pseudomallei is also classified as a tier I select agent due to the high level of lethality of the bacterium and its innate resistance to antibiotics, as well as the lack of an effective vaccine. Gram-negative bacteria, including B. pseudomallei, secrete outer membrane vesicles (OMVs) which are enriched with multiple protein, lipid, and polysaccharide antigens. Previously, we demonstrated that immunization with multivalent B. pseudomallei-derived OMVs protects highly susceptible BALB/c mice against an otherwise lethal aerosol challenge. In this work, we evaluated the protective efficacy of OMV immunization against intraperitoneal challenge with a heterologous strain because systemic infection with phenotypically diverse environmental B. pseudomallei strains poses another hazard and a challenge to vaccine development. We demonstrated that B. pseudomallei OMVs derived from strain 1026b afforded significant protection against septicemic infection with B. pseudomallei strain K96243. OMV immunization induced robust OMV-, lipopolysaccharide-, and capsular polysaccharide-specific serum IgG (IgG1, IgG2a, and IgG3) and IgM antibody responses. OMV-immune serum promoted bacterial killing in vitro, and passive transfer of B. pseudomallei OMV immune sera protected naive mice against a subsequent challenge. These results indicate that OMV immunization provides antibody-mediated protection against acute, rapidly lethal sepsis in mice. B. pseudomallei-derived OMVs may represent an efficacious multivalent vaccine strategy against melioidosis. PMID:24671550

Nieves, Wildaliz; Petersen, Hailey; Judy, Barbara M; Blumentritt, Carla A; Russell-Lodrigue, Kasi; Roy, Chad J; Torres, Alfredo G; Morici, Lisa A

2014-05-01

106

A Burkholderia pseudomallei Colony Variant Necessary for Gastric Colonization  

PubMed Central

ABSTRACT? Diverse colony morphologies are a hallmark of Burkholderia pseudomallei recovered from infected patients. We observed that stresses that inhibit aerobic respiration shifted populations of B. pseudomallei from the canonical white colony morphotype toward two distinct, reversible, yet relatively stable yellow colony variants (YA and YB). As accumulating evidence supports the importance of B. pseudomallei enteric infection and gastric colonization, we tested the response of yellow variants to hypoxia, acidity, and stomach colonization. Yellow variants exhibited a competitive advantage under hypoxic and acidic conditions and alkalized culture media. The YB variant, although highly attenuated in acute virulence, was the only form capable of colonization and persistence in the murine stomach. The accumulation of extracellular DNA (eDNA) was a characteristic of YB as observed by 4?,6-diamidino-2-phenylindole (DAPI) staining of gastric tissues, as well as in an in vitro stomach model where large amounts of eDNA were produced without cell lysis. Transposon mutagenesis identified a transcriptional regulator (BPSL1887, designated YelR) that when overexpressed produced the yellow phenotype. Deletion of yelR blocked a shift from white to the yellow forms. These data demonstrate that YB is a unique B. pseudomallei pathovariant controlled by YelR that is specifically adapted to the harsh gastric environment and necessary for persistent stomach colonization. IMPORTANCE? Seemingly uniform populations of bacteria often contain subpopulations that are genetically identical but display unique characteristics which offer advantages when the population is faced with infrequent but predictable stresses. The pathogen Burkholderia pseudomallei is capable of forming several reversible colony types, and it interconverted between one white type and two yellow types under certain environmental stresses. The two yellow forms exhibited distinct advantages in low-oxygen and acidic environments. One yellow colony variant was the only form capable of chronic stomach colonization. Areas of gastric infection were marked by bacteria encased in a DNA matrix, and the yellow forms were able to produce large amounts of extracellular DNA in vitro. We also identified the regulator in control of yellow colony variant formation. These findings demonstrate a role in infection for colony variation and provide a mechanism for chronic stomach colonization—a frequently overlooked niche in melioidosis. PMID:25650400

Austin, C. R.; Goodyear, A. W.; Bartek, I. L.; Stewart, A.; Sutherland, M. D.; Silva, E. B.; Zweifel, A.; Vitko, N. P.; Tuanyok, A.; Highnam, G.; Mittelman, D.; Keim, P.; Schweizer, H. P.; Vázquez-Torres, A.; Dow, S. W. C.

2015-01-01

107

Genetic control of weight loss during pneumonic Burkholderia pseudomallei infection.  

PubMed

Burkholderia pseudomallei (Bp) is the causal agent of a high-morbidity/mortality disease syndrome known as melioidosis. This syndrome can range from acute fulminate disease to chronic, local, and disseminated infections that are often difficult to treat because Bp exhibits resistance to many antibiotics. Bp is a prime candidate for use in biologic warfare/terrorism and is classified as a Tier-1 select agent by HHS and APHIS. It is known that inbred mouse strains display a range of susceptibility to Bp and that the murine infection model is ideal for studying acute melioidosis. Here, we exploit a powerful mouse genetics resource that consists of a large family of BXD-type recombinant inbred strains, to perform genome-wide linkage analysis of the weight loss phenotype following pneumonic infection with Bp. We infected parental mice and 32 BXD strains with 50-100 CFU of Bp (strain 1026b) and monitored weight retention each day over an eleven-day time course. Using the computational tools in GeneNetwork, we performed genome-wide linkage analysis to identify an interval on chromosome 12 that appears to control the weight retention trait. We then analyzed and ranked positional candidate genes in this interval, several of which have intriguing connections with innate immunity, calcium homeostasis, lipid transport, host cell growth and development, and autophagy. PMID:24687986

Emery, Felicia D; Parvathareddy, Jyothi; Pandey, Ashutosh K; Cui, Yan; Williams, Robert W; Miller, Mark A

2014-07-01

108

Correlates of Immune Protection following Cutaneous Immunization with an Attenuated Burkholderia pseudomallei Vaccine  

PubMed Central

Infections with the Gram-negative bacterium Burkholderia pseudomallei (melioidosis) are associated with high mortality, and there is currently no approved vaccine to prevent the development of melioidosis in humans. Infected patients also do not develop protective immunity to reinfection, and some individuals will develop chronic, subclinical infections with B. pseudomallei. At present, our understanding of what constitutes effective protective immunity against B. pseudomallei infection remains incomplete. Therefore, we conducted a study to elucidate immune correlates of vaccine-induced protective immunity against acute B. pseudomallei infection. BALB/c and C57BL/6 mice were immunized subcutaneously with a highly attenuated, Select Agent-excluded purM deletion mutant of B. pseudomallei (strain Bp82) and then subjected to intranasal challenge with virulent B. pseudomallei strain 1026b. Immunization with Bp82 generated significant protection from challenge with B. pseudomallei, and protection was associated with a significant reduction in bacterial burden in lungs, liver, and spleen of immunized mice. Humoral immunity was critically important for vaccine-induced protection, as mice lacking B cells were not protected by immunization and serum from Bp82-vaccinated mice could transfer partial protection to nonvaccinated animals. In contrast, vaccine-induced protective immunity was found to be independent of both CD4 and CD8 T cells. Tracking studies demonstrated uptake of the Bp82 vaccine strain predominately by neutrophils in vaccine-draining lymph nodes and by smaller numbers of dendritic cells (DC) and monocytes. We concluded that protection following cutaneous immunization with a live attenuated Burkholderia vaccine strain was dependent primarily on generation of effective humoral immune responses. PMID:24101688

Silva, Ediane B.; Goodyear, Andrew; Sutherland, Marjorie D.; Podnecky, Nicole L.; Gonzalez-Juarrero, Mercedes; Schweizer, Herbert P.

2013-01-01

109

Raman spectroscopic detection and identification of Burkholderia mallei and Burkholderia pseudomallei in feedstuff.  

PubMed

Burkholderia mallei (the etiologic agent of glanders in equines and rarely humans) and Burkholderia pseudomallei, causing melioidosis in humans and animals, are designated category B biothreat agents. The intrinsically high resistance of both agents to many antibiotics, their potential use as bioweapons, and their low infectious dose, necessitate the need for rapid and accurate detection methods. Current methods to identify these organisms may require up to 1 week, as they rely on phenotypic characteristics and an extensive set of biochemical reactions. In this study, Raman microspectroscopy, a cultivation-independent typing technique for single bacterial cells with the potential for being a rapid point-of-care analysis system, is evaluated to identify and differentiate B. mallei and B. pseudomallei within hours. Here, not only broth-cultured microbes but also bacteria isolated out of pelleted animal feedstuff were taken into account. A database of Raman spectra allowed a calculation of classification functions, which were trained to differentiate Raman spectra of not only both pathogens but also of five further Burkholderia spp. and four species of the closely related genus Pseudomonas. The developed two-stage classification system comprising two support vector machine (SVM) classifiers was then challenged by a test set of 11 samples to simulate the case of a real-world-scenario, when "unknown samples" are to be identified. In the end, all test set samples were identified correctly, even if the contained bacterial strains were not incorporated in the database before or were isolated out of animal feedstuff. Specifically, the five test samples bearing B. mallei and B. pseudomallei were correctly identified on species level with accuracies between 93.9 and 98.7 %. The sample analysis itself requires no biomass enrichment step prior to the analysis and can be performed under biosafety level 1 (BSL 1) conditions after inactivating the bacteria with formaldehyde. PMID:24880875

Stöckel, Stephan; Meisel, Susann; Elschner, Mandy; Melzer, Falk; Rösch, Petra; Popp, Jürgen

2014-06-01

110

Substituted Diphenyl Ethers as a Novel Chemotherapeutic Platform against Burkholderia pseudomallei  

PubMed Central

Identification of a novel class of anti-Burkholderia compounds is key in addressing antimicrobial resistance to current therapies as well as naturally occurring resistance. The FabI enoyl-ACP reductase in Burkholderia is an underexploited target that presents an opportunity for development of a new class of inhibitors. A library of substituted diphenyl ethers was used to identify FabI1-specific inhibitors for assessment in Burkholderia pseudomallei ex vivo and murine efficacy models. Active FabI1 inhibitors were identified in a two-stage format consisting of percent inhibition screening and MIC determination by the broth microdilution method. Each compound was evaluated against the B. pseudomallei 1026b (efflux-proficient) and Bp400 (efflux-compromised) strains. In vitro screening identified candidate substituted diphenyl ethers that exhibited MICs of less than 1 ?g/ml, and enzyme kinetic assays were used to assess potency and specificity against the FabI1 enzyme. These compounds demonstrated activity in a Burkholderia ex vivo efficacy model, and two demonstrated efficacy in an acute B. pseudomallei mouse infection model. This work establishes substituted diphenyl ethers as a suitable platform for development of novel anti-Burkholderia compounds that can be used for treatment of melioidosis. PMID:24379198

Cummings, Jason E.; Beaupre, Adam J.; Knudson, Susan E.; Liu, Nina; Yu, Weixuan; Neckles, Carla; Wang, Hui; Khanna, Avinash; Bommineni, Gopal R.; Trunck, Lily A.; Schweizer, Herbert P.

2014-01-01

111

Substituted diphenyl ethers as a novel chemotherapeutic platform against Burkholderia pseudomallei.  

PubMed

Identification of a novel class of anti-Burkholderia compounds is key in addressing antimicrobial resistance to current therapies as well as naturally occurring resistance. The FabI enoyl-ACP reductase in Burkholderia is an underexploited target that presents an opportunity for development of a new class of inhibitors. A library of substituted diphenyl ethers was used to identify FabI1-specific inhibitors for assessment in Burkholderia pseudomallei ex vivo and murine efficacy models. Active FabI1 inhibitors were identified in a two-stage format consisting of percent inhibition screening and MIC determination by the broth microdilution method. Each compound was evaluated against the B. pseudomallei 1026b (efflux-proficient) and Bp400 (efflux-compromised) strains. In vitro screening identified candidate substituted diphenyl ethers that exhibited MICs of less than 1 ?g/ml, and enzyme kinetic assays were used to assess potency and specificity against the FabI1 enzyme. These compounds demonstrated activity in a Burkholderia ex vivo efficacy model, and two demonstrated efficacy in an acute B. pseudomallei mouse infection model. This work establishes substituted diphenyl ethers as a suitable platform for development of novel anti-Burkholderia compounds that can be used for treatment of melioidosis. PMID:24379198

Cummings, Jason E; Beaupre, Adam J; Knudson, Susan E; Liu, Nina; Yu, Weixuan; Neckles, Carla; Wang, Hui; Khanna, Avinash; Bommineni, Gopal R; Trunck, Lily A; Schweizer, Herbert P; Tonge, Peter J; Slayden, Richard A

2014-01-01

112

Distribution of Burkholderia pseudomallei in northern Australia, a land of diversity.  

PubMed

Burkholderia pseudomallei is a Gram-negative soil bacillus that is the etiological agent of melioidosis and a biothreat agent. Little is known about the biogeography of this bacterium in Australia, despite its hyperendemicity in the northern region of this continent. The population structure of 953 Australian B. pseudomallei strains representing 779 and 174 isolates of clinical and environmental origins, respectively, was analyzed using multilocus sequence typing (MLST). Bayesian population structure and network SplitsTree analyses were performed on concatenated MLST loci, and sequence type (ST) diversity and evenness were examined using Simpson's and Pielou's indices and a multivariate dissimilarity matrix. Bayesian analysis found two B. pseudomallei populations in Australia that were geographically distinct; isolates from the Northern Territory were grouped mainly into the first population, whereas the majority of isolates from Queensland were grouped in a second population. Differences in ST evenness were observed between sampling areas, confirming that B. pseudomallei is widespread and established across northern Australia, with a large number of fragmented habitats. ST analysis showed that B. pseudomallei populations diversified as the sampling area increased. This observation was in contrast to smaller sampling areas where a few STs predominated, suggesting that B. pseudomallei populations are ecologically established and not frequently dispersed. Interestingly, there was no identifiable ST bias between clinical and environmental isolates, suggesting the potential for all culturable B. pseudomallei isolates to cause disease. Our findings have important implications for understanding the ecology of B. pseudomallei in Australia and for potential source attribution of this bacterium in the event of unexpected cases of melioidosis. PMID:24657869

McRobb, Evan; Kaestli, Mirjam; Price, Erin P; Sarovich, Derek S; Mayo, Mark; Warner, Jeffrey; Spratt, Brian G; Currie, Bart J

2014-06-01

113

Distribution of Burkholderia pseudomallei in Northern Australia, a Land of Diversity  

PubMed Central

Burkholderia pseudomallei is a Gram-negative soil bacillus that is the etiological agent of melioidosis and a biothreat agent. Little is known about the biogeography of this bacterium in Australia, despite its hyperendemicity in the northern region of this continent. The population structure of 953 Australian B. pseudomallei strains representing 779 and 174 isolates of clinical and environmental origins, respectively, was analyzed using multilocus sequence typing (MLST). Bayesian population structure and network SplitsTree analyses were performed on concatenated MLST loci, and sequence type (ST) diversity and evenness were examined using Simpson's and Pielou's indices and a multivariate dissimilarity matrix. Bayesian analysis found two B. pseudomallei populations in Australia that were geographically distinct; isolates from the Northern Territory were grouped mainly into the first population, whereas the majority of isolates from Queensland were grouped in a second population. Differences in ST evenness were observed between sampling areas, confirming that B. pseudomallei is widespread and established across northern Australia, with a large number of fragmented habitats. ST analysis showed that B. pseudomallei populations diversified as the sampling area increased. This observation was in contrast to smaller sampling areas where a few STs predominated, suggesting that B. pseudomallei populations are ecologically established and not frequently dispersed. Interestingly, there was no identifiable ST bias between clinical and environmental isolates, suggesting the potential for all culturable B. pseudomallei isolates to cause disease. Our findings have important implications for understanding the ecology of B. pseudomallei in Australia and for potential source attribution of this bacterium in the event of unexpected cases of melioidosis. PMID:24657869

McRobb, Evan; Kaestli, Mirjam; Price, Erin P.; Sarovich, Derek S.; Mayo, Mark; Warner, Jeffrey; Spratt, Brian G.

2014-01-01

114

Novel gain of function approaches for vaccine candidate identification in Burkholderia pseudomallei  

PubMed Central

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. Categorization of the pathogen as a potential biowarfare agent has also made research into vaccine development a high priority. Recent genome-scale screening has produced a large number of putative gene candidates from B. pseudomallei with the potential for development into vaccines. This mini-review will discuss the advantages and limitations of this novel approach, how these new techniques can complement existing strategies, and outline aims for future research. PMID:23316481

Dowling, Andrea J.

2013-01-01

115

An objective approach for Burkholderia pseudomallei strain selection as challenge material for medical countermeasures efficacy testing.  

PubMed

Burkholderia pseudomallei is the causative agent of melioidosis, a rare disease of biodefense concern with high mortality and extreme difficulty in treatment. No human vaccines are available that protect against B. pseudomallei infection, and with the current limitations of antibiotic treatment, the development of new preventative and therapeutic interventions is crucial. Although clinical trials could be used to test the efficacy of new medical countermeasures (MCMs), the high mortality rates associated with melioidosis raises significant ethical issues concerning treating individuals with new compounds with unknown efficacies. The US Food and Drug Administration (FDA) has formulated a set of guidelines for the licensure of new MCMs to treat diseases in which it would be unethical to test the efficacy of these drugs in humans. The FDA "Animal Rule" 21 CFR 314 calls for consistent, well-characterized B. pseudomallei strains to be used as challenge material in animal models. In order to facilitate the efficacy testing of new MCMs for melioidosis using animal models, we intend to develop a well-characterized panel of strains for use. This panel will comprise of strains that were isolated from human cases, have a low passage history, are virulent in animal models, and are well-characterized phenotypically and genotypically. We have reviewed published and unpublished data on various B. pseudomallei strains to establish an objective method for selecting the strains to be included in the panel of B. pseudomallei strains with attention to five categories: animal infection models, genetic characterization, clinical and passage history, and availability of the strain to the research community. We identified 109 strains with data in at least one of the five categories, scored each strain based on the gathered data and identified six strains as candidate for a B. pseudomallei strain panel. PMID:23057010

Van Zandt, Kristopher E; Tuanyok, Apichai; Keim, Paul S; Warren, Richard L; Gelhaus, H Carl

2012-01-01

116

Antimicrobial and antibiofilm activity of LL-37 and its truncated variants against Burkholderia pseudomallei.  

PubMed

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 mechanisms of action of LL-37 and its truncated variants against B. pseudomallei both in planktonic and biofilm form, as LL-37 is an antimicrobial peptide that possessed strong killing activity against several pathogens. Antimicrobial assays revealed that LL-31, a truncated variant of LL-37 lacking the six C-terminus residues, exhibited the strongest killing effect. Time-kill experiments showed that 20 ?M LL-31 can reach the bactericidal endpoint within 2h. Freeze-fracture electron microscopy of bacterial cells demonstrated that these peptides disrupt the membrane and cause leakage of intracellular molecules leading to cell death. Moreover, LL-31 also possessed stronger bactericidal activity than ceftazidime against B. pseudomallei grown in biofilm. Thus, LL-31 should be considered as a potent antimicrobial agent against B. pseudomallei both in planktonic and biofilm form. PMID:22005071

Kanthawong, Sakawrat; Bolscher, Jan G M; Veerman, Enno C I; van Marle, Jan; de Soet, Hans J J; Nazmi, Kamran; Wongratanacheewin, Surasakdi; Taweechaisupapong, Suwimol

2012-01-01

117

Isolation of Polymyxin B-Susceptible Mutants of Burkholderia pseudomallei and Molecular Characterization of Genetic Loci Involved in Polymyxin B Resistance  

Microsoft Academic Search

Burkholderia pseudomallei is a gram-negative bacterium that causes the disease known as melioidosis. This pathogen is endemic to Southeast Asia and northern Australia and is particularly problematic in northeastern Thailand. It has been previously reported that B. pseudomallei is resistant to the killing action of cationic antimicrobial peptides, including human neutrophil peptide, protamine sulfate, poly-L-lysine, magainins, and polymyxins. Recently, we

MARY N. BURTNICK; DONALD E. WOODS

1999-01-01

118

Isolates of Burkholderia pseudomallei from Northern Australia Are Distinct by Multilocus Sequence Typing, but Strain Types Do Not Correlate with Clinical Presentation  

Microsoft Academic Search

Melioidosis is the disease caused by the saprophytic organism Burkholderia pseudomallei. Previous studies have suggested some strain tropism and differential virulence. In this study, we defined strains by multilocus sequence typing (MLST) of isolates taken from the Top End of Australia's Northern Territory and compared the results with those of other strains typed worldwide. We specifically sought clinical and geographical

Allen C. Cheng; Daniel Godoy; Mark Mayo; Daniel Gal; Brian G. Spratt; Bart J. Currie

2004-01-01

119

The PmlI-PmlR Quorum-Sensing System in Burkholderia pseudomallei Plays a Key Role in Virulence and Modulates Production of the MprA Protease  

Microsoft Academic Search

Burkholderia pseudomallei is the causative agent of melioidosis, an often fatal infection of humans and animals. The virulence of this pathogen is thought to depend on a number of secreted proteins, including the MprA metalloprotease. We observed that MprA is produced upon entry into the stationary phase, when the cell density is high, and this prompted us to study cell

E. Valade; F. M. Thibault; Y. P. Gauthier; M. Palencia; M. Y. Popoff; D. R. Vidal

2004-01-01

120

Liver abscess caused by Burkholderia pseudomallei in a young man: A case report and review of literature.  

PubMed

Pyogenic liver abscess is a common entity in Indian subcontinent and is mostly caused by gram negative bacteria. Melioidosis is not commonly seen in India and only a few cases are reported. It can give rise to multiple abscesses at different sites including liver. We report a case of isolated liver abscess caused by Burkholderia pseudomallei (B. pseudomallei) in a 29-year-old recently diagnosed diabetic, immunocompetent male. Diagnosis was made by imaging and culture of pus aspirated from the abscess and he was treated with percutaneous pigtail catheter drainage followed by antibiotics (meropenem and trimethoprim-sulphmethoxazole). Melioidosis is an emerging infection in India and has high mortality rate, so early diagnosis and prompt management is warranted which requires clinical vigilance and an intensive microbiological workup. Clinicians should be aware of isolated liver abscess caused by B. pseudomallei in appropriate clinical settings. PMID:25325075

Pal, Partha; Ray, Sayantan; Moulick, Avijit; Dey, Subhasis; Jana, Anirban; Banerjee, Kokila

2014-10-16

121

Liver abscess caused by Burkholderia pseudomallei in a young man: A case report and review of literature  

PubMed Central

Pyogenic liver abscess is a common entity in Indian subcontinent and is mostly caused by gram negative bacteria. Melioidosis is not commonly seen in India and only a few cases are reported. It can give rise to multiple abscesses at different sites including liver. We report a case of isolated liver abscess caused by Burkholderia pseudomallei (B. pseudomallei) in a 29-year-old recently diagnosed diabetic, immunocompetent male. Diagnosis was made by imaging and culture of pus aspirated from the abscess and he was treated with percutaneous pigtail catheter drainage followed by antibiotics (meropenem and trimethoprim-sulphmethoxazole). Melioidosis is an emerging infection in India and has high mortality rate, so early diagnosis and prompt management is warranted which requires clinical vigilance and an intensive microbiological workup. Clinicians should be aware of isolated liver abscess caused by B. pseudomallei in appropriate clinical settings. PMID:25325075

Pal, Partha; Ray, Sayantan; Moulick, Avijit; Dey, Subhasis; Jana, Anirban; Banerjee, Kokila

2014-01-01

122

Isolation, identification and characterization of Burkholderia pseudomallei from soil of coastal region of India.  

PubMed

Melioidosis is an emerging infectious disease caused by a free living soil dwelling Gram-negative bacterium Burkholderia pseudomallei. The disease is endemic to most parts of Southeast Asia and northern Australia and the organism has been isolated from moist soil and water. In India clinical cases are recently reported from the states of Tamilnadu, Kerala, Karnataka, Maharashtra, Orissa, Assam, West Bengal, Pondicherry and Tripura. This study is aimed to confirm the prevalence of this important bacterial species in soil samples collected from coastal areas of Tamilnadu. Forty five soil samples from five different sites were collected from Parangipettai, Tamilnadu and screened for the presence of B. pseudomallei. The study confirmed 4 isolates as B. pseudomallei with the help of conventional bacteriological methods and molecular methods that include; 16S rDNA sequencing, B. pseudomallei specific PCR, fliC gene RFLP and MALDI-TOF mass spectrometry based bacterial identification. This study reveals the prevalence and distribution of B. pseudomallei in the soil environment in coastal areas of southern India and further necessitates studies from other parts of the country. It will also be helpful to understand the distribution of B. pseudomallei and to access its epidemiological importance. PMID:25187882

Prakash, Archana; Thavaselvam, Duraipandian; Kumar, Ashu; Kumar, Ajith; Arora, Sonia; Tiwari, Sapana; Barua, Anita; Sathyaseelan, Kannusamy

2014-01-01

123

Antimicrobial Susceptibility and Genetic Characterisation of Burkholderia pseudomallei Isolated from Malaysian Patients  

PubMed Central

Burkholderia pseudomallei, the causative agent of melioidosis, is intrinsically resistant to many antibiotics. Ceftazidime (CAZ), the synthetic ?-lactam, is normally used as the first-line antibiotic therapy for treatment of melioidosis. However, acquired CAZ resistance can develop in vivo during treatment with CAZ, leading to mortality if therapy is not switched to a different antibiotic(s) in a timely manner. In this study, susceptibilities of 81 B. pseudomallei isolates to nine different antimicrobial agents were determined using the disk diffusion method, broth microdilution test and Etest. Highest percentage of susceptibility was demonstrated to CAZ, amoxicillin/clavulanic acid, meropenem, imipenem, and trimethoprim/sulfamethoxazole. Although these drugs demonstrated the highest percentage of susceptibility in B. pseudomallei, the overall results underline the importance of the emergence of resistance in this organism. PCR results showed that, of the 81 B. pseudomallei, six multidrug resistant (MDR) isolates carried bpeB, amrB, and BPSS1119 and penA genes. Genotyping of the isolates using random amplified polymorphic DNA analysis showed six different PCR fingerprinting patterns generated from the six MDR isolates clusters (A) and eight PCR fingerprinting patterns generated for the remaining 75 non-MDR isolates clusters (B). PMID:25379514

Khosravi, Yalda; Mariappan, Vanitha; Ng, Shet-Lee

2014-01-01

124

Within-Host Evolution of Burkholderia pseudomallei over a Twelve-Year Chronic Carriage Infection  

PubMed Central

ABSTRACT Burkholderia pseudomallei causes the potentially fatal disease melioidosis. It is generally accepted that B. pseudomallei is a noncommensal bacterium and that any culture-positive clinical specimen denotes disease requiring treatment. Over a 23-year study of melioidosis cases in Darwin, Australia, just one patient from 707 survivors has developed persistent asymptomatic B. pseudomallei carriage. To better understand the mechanisms behind this unique scenario, we performed whole-genome analysis of two strains isolated 139 months apart. During this period, B. pseudomallei underwent several adaptive changes. Of 23 point mutations, 78% were nonsynonymous and 43% were predicted to be deleterious to gene function, demonstrating a strong propensity for positive selection. Notably, a nonsense mutation inactivated the universal stress response sigma factor RpoS, with pleiotropic implications. The genome underwent substantial reduction, with four deletions in chromosome 2 resulting in the loss of 221 genes. The deleted loci included genes involved in secondary metabolism, environmental survival, and pathogenesis. Of 14 indels, 11 occurred in coding regions and 9 resulted in frameshift mutations that dramatically affected predicted gene products. Disproportionately, four indels affected lipopolysaccharide biosynthesis and modification. Finally, we identified a frameshift mutation in both P314 isolates within wcbR, an important component of the capsular polysaccharide I locus, suggesting virulence attenuation early in infection. Our study illustrates a unique clinical case that contrasts a high-consequence infectious agent with a long-term commensal infection and provides further insights into bacterial evolution within the human host. PMID:23860767

Price, Erin P.; Sarovich, Derek S.; Mayo, Mark; Tuanyok, Apichai; Drees, Kevin P.; Kaestli, Mirjam; Beckstrom-Sternberg, Stephen M.; Babic-Sternberg, James S.; Kidd, Timothy J.; Bell, Scott C.; Keim, Paul; Pearson, Talima; Currie, Bart J.

2013-01-01

125

An ensemble of structures of Burkholderia pseudomallei 2,3-bisphosphoglycerate-dependent phosphoglycerate mutase  

SciTech Connect

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 elucidated. Vanadate is a phosphate mimic that is a powerful tool for studying enzymatic mechanisms in phosphoryl-transfer enzymes such as phosphoglycerate mutase. However, to date no X-ray crystal structures of phosphoglycerate mutase have been solved with vanadate acting as a substrate mimic. Here, two vanadate complexes together with an ensemble of substrate and fragment-bound structures that provide a comprehensive picture of the function of the Burkholderia enzyme are reported.

Davies, Douglas R.; Staker, Bart L.; Abendroth, Jan A.; Edwards, Thomas E.; Hartley, Robert; Leonard, Jess; Kim, Hidong; Rychel, Amanda L.; Hewitt, Stephen N.; Myler, Peter J.; Stewart, Lance J. (UWASH); (Emerald)

2011-12-07

126

Biogeography of Burkholderia pseudomallei in the Torres Strait Islands of Northern Australia  

PubMed Central

It has been hypothesized that biogeographical boundaries are a feature of Burkholderia pseudomallei ecology, and they impact the epidemiology of melioidosis on a global scale. This study examined the relatedness of B. pseudomallei sourced from islands in the Torres Strait of Northern Australia to determine if the geography of isolated island communities is a determinant of the organisms' dispersal. Environmental sampling on Badu Island in the Near Western Island cluster recovered a single clone. An additional 32 clinical isolates from the region were sourced. Isolates were characterized using multilocus sequence typing and a multiplex PCR targeting the flagellum gene cluster. Gene cluster analysis determined that 69% of the isolates from the region encoded the ancestral Burkholderia thailandensis-like flagellum and chemotaxis gene cluster, a proportion significantly lower than that reported from mainland Australia and consistent with observations of isolates from southern Papua New Guinea. A goodness-of-fit test indicated that there was geographic localization of sequence types throughout the archipelago, with the exception of Thursday Island, the economic and cultural hub of the region. Sequence types common to mainland Australia and Papua New Guinea were identified. These findings demonstrate for the first time an environmental reservoir for B. pseudomallei in the Torres Strait, and multilocus sequence typing suggests that the organism is not randomly distributed throughout this region and that seawater may provide a barrier to dispersal of the organism. Moreover, these findings support an anthropogenic dispersal hypothesis for the spread of B. pseudomallei throughout this region. PMID:23698533

Baker, Anthony; Mayo, Mark; Owens, Leigh; Burgess, Graham; Norton, Robert; McBride, William John Hannan; Currie, Bart J.

2013-01-01

127

The Condition-Dependent Transcriptional Landscape of Burkholderia pseudomallei  

PubMed Central

Burkholderia pseudomallei (Bp), the causative agent of the often-deadly infectious disease melioidosis, contains one of the largest prokaryotic genomes sequenced to date, at 7.2 Mb with two large circular chromosomes (1 and 2). To comprehensively delineate the Bp transcriptome, we integrated whole-genome tiling array expression data of Bp exposed to >80 diverse physical, chemical, and biological conditions. Our results provide direct experimental support for the strand-specific expression of 5,467 Sanger protein-coding genes, 1,041 operons, and 766 non-coding RNAs. A large proportion of these transcripts displayed condition-dependent expression, consistent with them playing functional roles. The two Bp chromosomes exhibited dramatically different transcriptional landscapes — Chr 1 genes were highly and constitutively expressed, while Chr 2 genes exhibited mosaic expression where distinct subsets were expressed in a strongly condition-dependent manner. We identified dozens of cis-regulatory motifs associated with specific condition-dependent expression programs, and used the condition compendium to elucidate key biological processes associated with two complex pathogen phenotypes — quorum sensing and in vivo infection. Our results demonstrate the utility of a Bp condition-compendium as a community resource for biological discovery. Moreover, the observation that significant portions of the Bp virulence machinery can be activated by specific in vitro cues provides insights into Bp's capacity as an “accidental pathogen”, where genetic pathways used by the bacterium to survive in environmental niches may have also facilitated its ability to colonize human hosts. PMID:24068961

Nandi, Tannistha; Kreisberg, Jason F.; Chua, Hui Hoon; Sun, Guangwen; Chen, Yahua; Mueller, Claudia; Conejero, Laura; Eshaghi, Majid; Ang, Roy Moh Lik; Liu, Jianhua; Sobral, Bruno W.; Korbsrisate, Sunee; Gan, Yunn Hwen; Titball, Richard W.; Bancroft, Gregory J.; Valade, Eric; Tan, Patrick

2013-01-01

128

MyD88 Dependent Signaling Contributes to Protective Host Defense against Burkholderia pseudomallei  

PubMed Central

Background Toll-like receptors (TLRs) have a central role in the recognition of pathogens and the initiation of the innate immune response. Myeloid differentiation primary-response gene 88 (MyD88) and TIR-domain-containing adaptor protein inducing IFN? (TRIF) are regarded as the key signaling adaptor proteins for TLRs. Melioidosis, which is endemic in SE-Asia, is a severe infection caused by the gram-negative bacterium Burkholderia pseudomallei. We here aimed to characterize the role of MyD88 and TRIF in host defense against melioidosis. Methodology and Principal Findings First, we found that MyD88, but not TRIF, deficient whole blood leukocytes released less TNF? upon stimulation with B. pseudomallei compared to wild-type (WT) cells. Thereafter we inoculated MyD88 knock-out (KO), TRIF mutant and WT mice intranasally with B. pseudomallei and found that MyD88 KO, but not TRIF mutant mice demonstrated a strongly accelerated lethality, which was accompanied by significantly increased bacterial loads in lungs, liver and blood, and grossly enhanced liver damage compared to WT mice. The decreased bacterial clearance capacity of MyD88 KO mice was accompanied by a markedly reduced early pulmonary neutrophil recruitment and a diminished activation of neutrophils after infection with B. pseudomallei. MyD88 KO leukocytes displayed an unaltered capacity to phagocytose and kill B. pseudomallei in vitro. Conclusions MyD88 dependent signaling, but not TRIF dependent signaling, contributes to a protective host response against B. pseudomallei at least in part by causing early neutrophil recruitment towards the primary site of infection. PMID:18946505

Wiersinga, W. Joost; Wieland, Catharina W.; Roelofs, Joris J. T. H.; van der Poll, Tom

2008-01-01

129

Reliability of automated biochemical identification of Burkholderia pseudomallei is regionally dependent.  

PubMed

Misidentifications of Burkholderia pseudomallei as Burkholderia cepacia by Vitek 2 have occurred. Multidimensional scaling ordination of biochemical profiles of 217 Malaysian and Australian B. pseudomallei isolates found clustering of misidentified B. pseudomallei isolates from Malaysian Borneo. Specificity of B. pseudomallei identification in Vitek 2 and potentially other automated identification systems is regionally dependent. PMID:23784129

Podin, Yuwana; Kaestli, Mirjam; McMahon, Nicole; Hennessy, Jann; Ngian, Hie Ung; Wong, Jin Shyan; Mohana, Anand; Wong, See Chang; William, Timothy; Mayo, Mark; Baird, Robert W; Currie, Bart J

2013-09-01

130

Isolation of the highly pathogenic and zoonotic agent Burkholderia pseudomallei from a pet green Iguana in Prague, Czech Republic.  

PubMed

Background Melioidosis caused by Burkholderia (B.) pseudomallei is an endemic zoonotic disease mainly reported from northern Australia and Southeast Asia. In Europe, cases of human melioidosis have been reported only from patients travelling to endemic regions. Besides humans, B. pseudomallei has a very broad host range in domestic and wild animals. There are some reports about importation of B. pseudomallei-infected animals from endemic areas into Europe. The present report describes the first case of B. pseudomallei infection of a pet iguana in Europe.Case presentationIn a 5-year-old pet Iguana iguana living in a private household in Prague, Czech Republic, B. pseudomallei was isolated from pus of an abscess. The isolate VB976100 was identified by Vitek®2, MALDI-TOF mass spectrometry and polymerase chain reaction as B. pseudomallei. The molecular typing resulted in multi-locus sequence type 436 hitherto, which has been found only once worldwide in a B. pseudomallei strain isolated in the USA and originating from Guatemala. The identification as internal transcribed spacer type G indicates a close relatedness to strains mainly isolated in the Western Hemisphere. These findings support the hypothesis that the iguana became infected in this region or in a breeding facility through contact to other infected animals.ConclusionsThe present case highlights the risk of importation of the highly pathogenic and zoonotic B. pseudomallei into non-endemic regions through animal trade. Therefore, veterinarians treating animals from these areas and physicians examining patients owning such animals should include melioidosis in differential diagnosis whenever specific symptoms appear. Furthermore, veterinary authorities responsible for supervision of traders and pet shops should be aware of this risk of zoonotic transmission. PMID:25430942

Elschner, Mandy C; Hnizdo, Jan; Stamm, Ivonne; El-Adawy, Hosny; Mertens, Katja; Melzer, Falk

2014-11-28

131

Septicaemic Melioidosis: Case Report from a Non-Endemic Area  

PubMed Central

Melioidosis is a clinically diverse disease caused by the facultative intracellular Gram-negative bacterium, Burkholderia pseudomallei. In recent times melioidosis has been increasingly reported in India especially from the southern and coastal states. We report a fatal case of septicaemic melioidosis from the state of Rajasthan with a view to increase awareness about the existence of this disease in an area yet unrecognized.

Khedar, Raghuvir Singh; Joad, Shabbar HK; Gupta, Rajeev

2014-01-01

132

Activation of NADPH oxidase is essential, but not sufficient, in controlling intracellular multiplication of Burkholderia pseudomallei in primary human monocytes.  

PubMed

Burkholderia pseudomallei is a Gram-negative intracellular bacterium and the causative agent of melioidosis. Innate immune mechanisms against this pathogen, which might contribute to outcomes of melioidosis, are little known. We demonstrated here that B. pseudomallei could activate NADPH oxidase in primary human monocytes as judged by production of reactive oxygen species (ROS) and p40(phox) phosphorylation after infection. However, as similar to other intracellular bacteria, this bacterium was able to resist and multiply inside monocytes despite being able to activate NADPH oxidase. In the presence of NADPH oxidase inhibitor, diphenyleneiodonium or apocynin, intracellular multiplication of B. pseudomallei was significantly increased, suggesting that NADPH oxidase-mediated ROS production is essential in suppressing intracellular multiplication of B. pseudomallei. Additionally, interferon-? (IFN-?)-mediated intracellular killing of B. pseudomallei requires NADPH oxidase activity, even though ROS level was not detected at higher levels in IFN-?-treated infected monocytes. Altogether, these results imply that the activation of NADPH plays an essential role in suppressing intracellular multiplication of B. pseudomallei in human monocytes, although this enzyme is not sufficient to stop intracellular multiplication. PMID:24376210

Wikraiphat, Chanthiwa; Pudla, Matsayapan; Baral, Pankaj; Kitthawee, Sangvorn; Utaisincharoen, Pongsak

2014-06-01

133

Development and Validation of Burkholderia pseudomallei-Specific Real-Time PCR Assays for Clinical, Environmental or Forensic Detection Applications  

PubMed Central

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 assays for B. pseudomallei detection lack rigorous validation across large in silico datasets and isolate collections to test for specificity, and none have been subjected to stringent quality control criteria (accuracy, precision, selectivity, limit of quantitation (LoQ), limit of detection (LoD), linearity, ruggedness and robustness) to determine their suitability for environmental, clinical or forensic investigations. In this study, we developed two novel B. pseudomallei specific assays, 122018 and 266152, using a dual-probe approach to differentiate B. pseudomallei from B. thailandensis, B. oklahomensis and B. thailandensis-like species; other species failed to amplify. Species specificity was validated across a large DNA panel (>2,300 samples) comprising Burkholderia spp. and non-Burkholderia bacterial and fungal species of clinical and environmental relevance. Comparison of assay specificity to two previously published B. pseudomallei-specific assays, BurkDiff and TTS1, demonstrated comparable performance of all assays, providing between 99.7 and 100% specificity against our isolate panel. Last, we subjected 122018 and 266152 to rigorous quality control analyses, thus providing quantitative limits of assay performance. Using B. pseudomallei as a model, our study provides a framework for comprehensive quantitative validation of molecular assays and provides additional, highly validated B. pseudomallei assays for the scientific research community. PMID:22624061

Price, Erin P.; Dale, Julia L.; Cook, James M.; Sarovich, Derek S.; Seymour, Meagan L.; Ginther, Jennifer L.; Kaufman, Emily L.; Beckstrom-Sternberg, Stephen M.; Mayo, Mark; Kaestli, Mirjam; Glass, Mindy B.; Gee, Jay E.; Wuthiekanun, Vanaporn; Warner, Jeffrey M.; Baker, Anthony; Foster, Jeffrey T.; Tan, Patrick; Tuanyok, Apichai; Limmathurotsakul, Direk; Peacock, Sharon J.; Currie, Bart J.; Wagner, David M.; Keim, Paul; Pearson, Talima

2012-01-01

134

Failure of Burkholderia pseudomallei to Grow in an Automated Blood Culture System  

PubMed Central

We compared the organisms isolated from 30,210 pairs of blood culture bottles by using BacT/Alert system and the conventional system. Overall, 2,575 (8.5%) specimens were culture positive for pathogenic organisms. The sensitivity for detection of pathogenic organisms with the BACT/Alert system (85.6%, 2,203 of 2,575) was significantly higher than that with the conventional method (74.1%, 1,908 of 2,575; P < 0.0001). However, Burkholderia pseudomallei was isolated less often with the BacT/ALERT system (73.5%, 328 of 446) than with the conventional system (90.3%, 403 of 446; P < 0.0001). This finding suggests that use of the conventional culture method in conjunction with the BacT/Alert system may improve the isolation rate for B. pseudomallei in melioidosis-endemic areas. PMID:25311697

Teerawattanasook, Nittaya; Limmathurotsakul, Direk; Day, Nicholas P. J.; Wuthiekanun, Vanaporn

2014-01-01

135

Crystallization and preliminary crystallographic studies of the hypothetical protein BPSL1038 from Burkholderia pseudomallei.  

PubMed

Melioidosis is an infectious disease caused by the pathogenic bacterium Burkholderia pseudomallei. Whole-genome sequencing revealed that the B. pseudomallei genome includes 5855 coding DNA sequences (CDSs), of which ?25% encode hypothetical proteins. A pathogen-associated hypothetical protein, BPSL1038, was overexpressed in Escherichia coli, purified and crystallized using vapour-diffusion methods. A BPSL1038 protein crystal that grew using sodium formate as precipitant diffracted to 1.55?Å resolution. It belonged to space group C2221, with unit-cell parameters a = 85.36, b = 115.63, c = 46.73?Å. The calculated Matthews coefficient (VM) suggests that there are two molecules per asymmetric unit, with a solvent content of 48.8%. PMID:25484229

Shaibullah, Sofiyah; Mohd-Sharif, Nurhikmah; Ho, Kok Lian; Firdaus-Raih, Mohd; Nathan, Sheila; Mohamed, Rahmah; Ng, Chyan Leong

2014-12-01

136

Exploiting the Burkholderia pseudomallei acute phase antigen BPSL2765 for structure-based epitope discovery/design in structural vaccinology.  

PubMed

We solved the crystal structure of Burkholderia pseudomallei acute phase antigen BPSL2765 in the context of a structural vaccinology study, in the area of melioidosis vaccine development. Based on the structure, we applied a recently developed method for epitope design that combines computational epitope predictions with in vitro mapping experiments and successfully identified a consensus sequence within the antigen that, when engineered as a synthetic peptide, was selectively immunorecognized to the same extent as the recombinant protein in sera from melioidosis-affected subjects. Antibodies raised against the consensus peptide were successfully tested in opsonization bacterial killing experiments and antibody-dependent agglutination tests of B. pseudomallei. Our strategy represents a step in the development of immunodiagnostics, in the production of specific antibodies and in the optimization of antigens for vaccine development, starting from structural and physicochemical principles. PMID:23993463

Gourlay, Louise J; Peri, Claudio; Ferrer-Navarro, Mario; Conchillo-Solé, Oscar; Gori, Alessandro; Rinchai, Darawan; Thomas, Rachael J; Champion, Olivia L; Michell, Stephen L; Kewcharoenwong, Chidchamai; Nithichanon, Arnone; Lassaux, Patricia; Perletti, Lucia; Longhi, Renato; Lertmemongkolchai, Ganjana; Titball, Richard W; Daura, Xavier; Colombo, Giorgio; Bolognesi, Martino

2013-09-19

137

SHORT REPORT: A RAPID METHOD FOR THE DIFFERENTIATION OF BURKHOLDERIA PSEUDOMALLEI AND BURKHOLDERIA THAILANDENSIS  

Microsoft Academic Search

A rapid method for the identification and differentiation of Burkholderia pseudomallei and Burkholderia thailandensis colonies is described. It consists of simultaneous use of 2 monoclonal antibody-based latex agglutination test systems. The anti-lipopolysaccharide test reacts with both species, whereas the anti-exopolysaccharide reacts only with B. pseudomallei. Compared with classical biochemical tests, the method is highly reproducibleand accurate . It is particularly

VANAPORN WUTHIEKANUN; NARISARA ANUNTAGOOL; NICHOLAS J. WHITE; STITAYA SIRISINHA

2002-01-01

138

Screening for potential anti-infective agents towards Burkholderia pseudomallei infection  

NASA Astrophysics Data System (ADS)

The established treatment for melioidosis is antibiotic therapy. However, a constant threat to this form of treatment is resistance development of the causative agent, Burkholderia pseudomallei, towards antibiotics. One option to circumvent this threat of antibiotic resistance is to search for new alternative anti-infectives which target the host innate immune system and/or bacterial virulence. In this study, 29 synthetic compounds were evaluated for their potential to increase the lifespan of an infected host. The nematode Caenorhabditis elegans was adopted as the infection model as its innate immune pathways are homologous to humans. Screens were performed in a liquid-based survival assay containing infected worms exposed to individual compounds and survival of untreated and compound-treated worms were compared. A primary screen identified nine synthetic compounds that extended the lifespan of B. pseudomallei-infected worms. Subsequently, a disc diffusion test was performed on these selected compounds to delineate compounds into those that enhanced the survival of worms via antimicrobial activity i.e. reducing the number of infecting bacteria, or into those that did not target pathogen viability. Out of the nine hits selected, two demonstrated antimicrobial effects on B. pseudomallei. Therefore, the findings from this study suggest that the other seven identified compounds are potential anti-infectives which could protect a host against B. pseudomallei infection without developing the risk of drug resistance.

Eng, Su Anne; Nathan, Sheila

2014-09-01

139

Antibiotic susceptibility of 65 isolates of Burkholderia pseudomallei and Burkholderia mallei to 35 antimicrobial agents  

Microsoft Academic Search

Objectives: Fifty isolates of Burkholderia pseudomallei and 15 isolates of Burkholderia mallei were tested for their susceptibilities to 35 antimicrobial agents, including agents not previously tested against these bacteria. Methods: MICs were determined by agar dilution in Mueller-Hinton medium. Results: Among the antibiotics tested, lower MICs were obtained with imipenem, ceftazidime, piperacil- lin, piperacillin\\/tazobactam, doxycycline and minocycline. Fluoroquinolones and aminoglycosides

F. M. Thibault; E. Hernandez; D. R. Vidal; M. Girardet; D. Cavallo

2004-01-01

140

Porin Involvement in Cephalosporin and Carbapenem Resistance of Burkholderia pseudomallei  

PubMed Central

Background Burkholderia pseudomallei (Bps) is a Gram-negative bacterium that causes frequently lethal melioidosis, with a particularly high prevalence in the north and northeast of Thailand. Bps is highly resistant to many antimicrobial agents and this resistance may result from the low drug permeability of outer membrane proteins, known as porins. Principal Findings Microbiological assays showed that the clinical Bps strain was resistant to most antimicrobial agents and sensitive only to ceftazidime and meropenem. An E. coli strain defective in most porins, but expressing BpsOmp38, exhibited considerably lower antimicrobial susceptibility than the control strain. In addition, mutation of Tyr119, the most prominent pore-lining residue in BpsOmp38, markedly altered membrane permeability, substitution with Ala (mutant BpsOmp38Y119A) enhanced uptake of the antimicrobial agents, while substitution with Phe (mutant BpsOmp38Y119F) inhibited uptake. Channel recordings of BpsOmp38 reconstituted in a planar black lipid membrane (BLM) suggested that the higher permeability of BpsOmp38Y119A was caused by widening of the pore interior through removal of the bulky side chain. In contrast, the lower permeability of BpsOmp38Y119F was caused by introduction of the hydrophobic side chain (Phe), increasing the ‘greasiness’ of the pore lumen. Significantly, liposome swelling assays showed no permeation through the BpsOmp38 channel by antimicrobial agents to which Bps is resistant (cefoxitin, cefepime, and doripenem). In contrast, high permeability to ceftazidime and meropenem was observed, these being agents to which Bps is sensitive. Conclusion/Significance Our results, from both in vivo and in vitro studies, demonstrate that membrane permeability associated with BpsOmp38 expression correlates well with the antimicrobial susceptibility of the virulent bacterium B. pseudomallei, especially to carbapenems and cephalosporins. In addition, substitution of the residue Tyr119 affects the permeability of the BpsOmp38 channel to neutral sugars and antimicrobial agents. PMID:24788109

Aunkham, Anuwat; Schulte, Albert; Winterhalter, Mathias; Suginta, Wipa

2014-01-01

141

Protease production by Burkholderia pseudomallei and virulence in mice  

Microsoft Academic Search

The aim of this study was to assess protease production and virulence of various Burkholderia pseudomallei strains. Protease activity was evaluated in filtrates from cultures grown for 50 h in TSB Dialysate by azocasein hydrolysis, and expressed as absorbancy at 405 nm. Virulence was assessed in 8 weeks old SWISS mice, by intraperitoneal injection of 6–6×105 CFU, and the LD50

Y. P Gauthier; F. M Thibault; J. C Paucod; D. R Vidal

2000-01-01

142

Use of a Safe, Reproducible, and Rapid Aerosol Delivery Method to Study Infection by Burkholderia pseudomallei and Burkholderia mallei in Mice  

PubMed Central

Burkholderia pseudomallei, the etiologic agent of melioidosis, is a saprophytic bacterium readily isolated from wet soils of countries bordering the equator. Burkholderia mallei is a host-adapted clone of B. pseudomallei that does not persist outside of its equine reservoir and causes the zoonosis glanders, which is endemic in Asia, Africa, the Middle East and South America. Infection by these organisms typically occurs via percutaneous inoculation or inhalation of aerosols, and the most common manifestation is severe pneumonia leading to fatal bacteremia. Glanders and melioidosis are difficult to diagnose and require prolonged antibiotic therapy with low success rates. There are no vaccines available to protect against either Burkholderia species, and there is concern regarding their use as biological warfare agents given that B. mallei has previously been utilized in this manner. Hence, experiments were performed to establish a mouse model of aerosol infection to study the organisms and develop countermeasures. Using a hand-held aerosolizer, BALB/c mice were inoculated intratracheally with strains B. pseudomallei 1026b and B. mallei ATCC23344 and growth of the agents in the lungs, as well as dissemination to the spleen, were examined. Mice infected with 102, 103 and 104 organisms were unable to control growth of B. mallei in the lungs and bacteria rapidly disseminated to the spleen. Though similar results were observed in mice inoculated with 103 and 104 B. pseudomallei cells, animals infected with 102 organisms controlled bacterial replication in the lungs, dissemination to the spleen, and the extent of bacteremia. Analysis of sera from mice surviving acute infection revealed that animals produced antibodies against antigens known to be targets of the immune response in humans. Taken together, these data show that small volume aerosol inoculation of mice results in acute disease, dose-dependent chronic infection, and immune responses that correlate with those seen in human infections. PMID:24098563

Lafontaine, Eric R.; Zimmerman, Shawn M.; Shaffer, Teresa L.; Michel, Frank; Gao, Xiudan; Hogan, Robert J.

2013-01-01

143

Burkholderia pseudomallei in soil samples from an oceanarium in Hong Kong detected using a sensitive PCR assay  

PubMed Central

Melioidosis, caused by Burkholderia pseudomallei, is an emerging infectious disease with an expanding geographical distribution. Although assessment of the environmental load of B. pseudomallei is important for risk assessment in humans or animals in endemic areas, traditional methods of bacterial culture for isolation have low sensitivities and are labor-intensive. Using a specific polymerase chain reaction (PCR) assay targeting a Tat domain protein in comparison with a bacterial culture method, we examined the prevalence of B. pseudomallei in soil samples from an oceanarium in Hong Kong where captive marine mammals and birds have contracted melioidosis. Among 1420 soil samples collected from various sites in the oceanarium over a 15-month period, B. pseudomallei was detected in nine (0.6%) soil samples using bacterial culture, whereas it was detected in 96 (6.8%) soil samples using the specific PCR assay confirmed by sequencing. The PCR-positive samples were detected during various months, with higher detection rates observed during summer months. Positive PCR detection was significantly correlated with ambient temperature (P<0.0001) and relative humidity (P=0.011) but not with daily rainfall (P=0.241) or a recent typhoon (P=0.787). PCR-positive samples were obtained from all sampling locations, with the highest detection rate in the valley. Our results suggest that B. pseudomallei is prevalent and endemic in the oceanarium. The present PCR assay is more sensitive than the bacterial culture method, and it may be used to help better assess the transmission of melioidosis and to design infection control measures for captive animals in this unique and understudied environment.

Lau, Susanna KP; Chan, San-Yuen; Curreem, Shirly OT; Hui, Suk-Wai; Lau, Candy CY; Lee, Paul; Ho, Chi-Chun; Martelli, Paolo; Woo, Patrick CY

2014-01-01

144

Highly Sensitive Direct Detection and Quantification of Burkholderia pseudomallei Bacteria in Environmental Soil Samples by Using Real-Time PCR ? †  

PubMed Central

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 for 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 established a protocol for B. pseudomallei soil DNA isolation, purification, and quantification by quantitative PCR (qPCR) targeting a type three secretion system 1 single-copy gene. This assay was validated using 40 soil samples from Northeast Thailand that underwent parallel bacteriological culture. All 26 samples that were B. pseudomallei positive by direct culture were B. pseudomallei qPCR positive, with a median of 1.84 × 104 genome equivalents (range, 3.65 × 102 to 7.85 × 105) per gram of soil, assuming complete recovery of DNA. This was 10.6-fold (geometric mean; range, 1.1- to 151.3-fold) higher than the bacterial count defined by direct culture. Moreover, the qPCR detected B. pseudomallei in seven samples (median, 36.9 genome equivalents per g of soil; range, 9.4 to 47.3) which were negative by direct culture. These seven positive results were reproduced using a nested PCR targeting a second, independent B. pseudomallei-specific sequence. Two samples were direct culture and qPCR negative but nested PCR positive. Five samples were negative by both PCR methods and culture. In conclusion, our PCR-based system provides a highly specific and sensitive tool for the quantitative environmental surveillance of B. pseudomallei. PMID:21803915

Trung, Trinh Thanh; Hetzer, Adrian; Göhler, André; Topfstedt, Eylin; Wuthiekanun, Vanaporn; Limmathurotsakul, Direk; Peacock, Sharon J.; Steinmetz, Ivo

2011-01-01

145

Identification of the conserved hypothetical protein BPSL0317 in Burkholderia pseudomallei K96243  

NASA Astrophysics Data System (ADS)

Burkholderia pseudomallei K96243 is the causative agent of melioidosis, a disease which is endemic in Northern Australia and Southeastern Asia. The genome encodes several essential proteins including those currently annotated as hypothetical proteins. We studied the conservation and the essentiality of expressed hypothetical proteins in normal and different stress conditions. Based on the comparative genomics, we identified a hypothetical protein, BPSL0317, a potential essential gene that is being expressed in all normal and stress conditions. BPSL0317 is also phylogenetically conserved in the Burkholderiales order suggesting that this protein is crucial for survival among the order's members. BPSL0317 therefore has a potential to be a candidate antimicrobial drug target for this group of bacteria.

Yusoff, Nur Syamimi; Damiri, Nadzirah; Firdaus-Raih, Mohd

2014-09-01

146

The detection of insertion sequences within the human pathogen Burkholderia pseudomallei which have been identified previously in Burkholderia cepacia  

Microsoft Academic Search

Using primers designed from the nucleotide sequences of five insertion elements identified previously in Burkholderia cepacia, the presence of two insertion sequences (IS406 and IS407) was detected in chromosomal DNA isolated from strains of the human pathogen Burkholderia pseudomallei. The IS407 homologue was cloned from B. pseudomallei NCTC 4845 and nucleotide sequenced to confirm its identity and degree of homology

Kerri Mack; Richard W Titball

1998-01-01

147

Characterization of BcaA, a Putative Classical Autotransporter Protein in Burkholderia pseudomallei  

PubMed Central

Burkholderia pseudomallei is a tier 1 select agent, and the causative agent of melioidosis, a disease with effects ranging from chronic abscesses to fulminant pneumonia and septic shock, which can be rapidly fatal. Autotransporters (ATs) are outer membrane proteins belonging to the type V secretion system family, and many have been shown to play crucial roles in pathogenesis. The open reading frame Bp1026b_II1054 (bcaA) in B. pseudomallei strain 1026b is predicted to encode a classical autotransporter protein with an approximately 80-kDa passenger domain that contains a subtilisin-related domain. Immediately 3? to bcaA is Bp11026_II1055 (bcaB), which encodes a putative prolyl 4-hydroxylase. To investigate the role of these genes in pathogenesis, large in-frame deletion mutations of bcaA and bcaB were constructed in strain Bp340, an efflux pump mutant derivative of the melioidosis clinical isolate 1026b. Comparison of Bp340?bcaA and Bp340?bcaB mutants to wild-type B. pseudomallei in vitro demonstrated similar levels of adherence to A549 lung epithelial cells, but the mutant strains were defective in their ability to invade these cells and to form plaques. In a BALB/c mouse model of intranasal infection, similar bacterial burdens were observed after 48 h in the lungs and liver of mice infected with Bp340?bcaA, Bp340?bcaB, and wild-type bacteria. However, significantly fewer bacteria were recovered from the spleen of Bp340?bcaA-infected mice, supporting the idea of a role for this AT in dissemination or in survival in the passage from the site of infection to the spleen. PMID:23340315

Campos, Cristine G.; Borst, Luke

2013-01-01

148

Quorum Sensing Negatively Regulates Multinucleate Cell Formation during Intracellular Growth of Burkholderia pseudomallei in Macrophage-Like Cells  

PubMed Central

Burkholderia pseudomallei is a Gram-negative environmental bacterium and the causative agent of melioidosis, a potentially fatal, acute or chronic disease endemic in the tropics. Acyl homoserine lactone (AHL)-mediated quorum sensing and signalling have been associated with virulence and biofilm formation in numerous bacterial pathogens. In the canonical acyl-homoserine lactone signalling paradigm, AHLs are detected by a response regulator. B. pseudomallei encodes three AHL synthases, encoded by bpsI1, bpsI2 and bpsI3, and five regulator genes. In this study, we mutated the B. pseudomallei AHL synthases individually and in double and triple combination. Five AHLs were detected and quantified by tandem liquid chromatography-mass spectroscopy. The major AHLs produced were N-octanoylhomoserine lactone and N-(3-hydroxy-decanoyl)homoserine lactone, the expression of which depended on bpsI1 and bpsI2, respectively. B. pseudomallei infection of macrophage cells causes cell fusion, leading to multinucleated cells (3 or more nuclei per cell). A triple mutant defective in production of all three AHL synthases was associated with a striking phenotype of massively enhanced host cellular fusion in macrophages. However, neither abrogation of host cell fusion, achieved by mutation of bimA or hcp1, nor enhancement of fusion altered intracellular replication of B. pseudomallei. Furthermore, when tested in murine models of acute melioidosis the AHL synthase mutants were not attenuated for virulence. Collectively, this study identifies important new aspects of the genetic basis of AHL synthesis in B. pseudomallei and the roles of these AHLs in systemic infection and in cell fusion in macrophages for this important human pathogen. PMID:23704903

Horton, Rachel E.; Grant, Gary D.; Matthews, Ben; Batzloff, Michael; Owen, Suzzanne J.; Kyan, Stephanie; Flegg, Cameron P.; Clark, Amanda M.; Ulett, Glen C.; Morrison, Nigel; Peak, Ian R.; Beacham, Ifor R.

2013-01-01

149

Autochthonous melioidosis in humans, Madagascar, 2012 and 2013.  

PubMed

Melioidosis is an often fatal infectious disease affecting humans and animals in the tropics. Only sporadic cases have been reported from Africa and the Indian Ocean region. We describe 2 confirmed autochthonous cases of human melioidosis in Madagascar, both from novel genotypes of Burkholderia pseudomallei. PMID:25272365

Garin, Benoit; Djaomazala, Innocente; Dubois-Cauwelaert, Natasha; Raharimanga, Vaomalala; Ralison, Fidiarivony; Herindrainy, Perlinot; Andriamalala, Nivosoa C; Sarovich, Derek S; Mayo, Mark; Kaestli, Mirjam; Currie, Bart J

2014-10-01

150

Autochthonous Melioidosis in Humans, Madagascar, 2012 and 2013  

PubMed Central

Melioidosis is an often fatal infectious disease affecting humans and animals in the tropics. Only sporadic cases have been reported from Africa and the Indian Ocean region. We describe 2 confirmed autochthonous cases of human melioidosis in Madagascar, both from novel genotypes of Burkholderia pseudomallei. PMID:25272365

Djaomazala, Innocente; Dubois-Cauwelaert, Natasha; Raharimanga, Vaomalala; Ralison, Fidiarivony; Herindrainy, Perlinot; Andriamalala, Nivosoa C.; Sarovich, Derek S.; Mayo, Mark; Kaestli, Mirjam; Currie, Bart J.

2014-01-01

151

The Multiple Roles of Hypothetical Gene BPSS1356 in Burkholderia pseudomallei  

PubMed Central

Burkholderia pseudomallei is an opportunistic pathogen and the causative agent of melioidosis. It is able to adapt to harsh environments and can live intracellularly in its infected hosts. In this study, identification of transcriptional factors that associate with the ?? subunit (RpoC) of RNA polymerase was performed. The N-terminal region of this subunit is known to trigger promoter melting when associated with a sigma factor. A pull-down assay using histidine-tagged B. pseudomallei RpoC N-terminal region as bait showed that a hypothetical protein BPSS1356 was one of the proteins bound. This hypothetical protein is conserved in all B. pseudomallei strains and present only in the Burkholderia genus. A BPSS1356 deletion mutant was generated to investigate its biological function. The mutant strain exhibited reduced biofilm formation and a lower cell density during the stationary phase of growth in LB medium. Electron microscopic analysis revealed that the ?BPSS1356 mutant cells had a shrunken cytoplasm indicative of cell plasmolysis and a rougher surface when compared to the wild type. An RNA microarray result showed that a total of 63 genes were transcriptionally affected by the BPSS1356 deletion with fold change values of higher than 4. The expression of a group of genes encoding membrane located transporters was concurrently down-regulated in ?BPSS1356 mutant. Amongst the affected genes, the putative ion transportation genes were the most severely suppressed. Deprivation of BPSS1356 also down-regulated the transcriptions of genes for the arginine deiminase system, glycerol metabolism, type III secretion system cluster 2, cytochrome bd oxidase and arsenic resistance. It is therefore obvious that BPSS1356 plays a multiple regulatory roles on many genes. PMID:24927285

Yam, Hokchai; Abdul Rahim, Ainihayati; Mohamad, Suriani; Mahadi, Nor Muhammad; Abdul Manaf, Uyub; Shu-Chien, Alexander Chong; Najimudin, Nazalan

2014-01-01

152

Characterization and mutagenesis of fur gene from Burkholderia pseudomallei  

Microsoft Academic Search

A homolog of the ferric uptake regulator gene (fur) was isolated from Burkholderia pseudomallei (Bp) by a reverse genetic technique. Sequencing of a 2.2kb DNA fragment revealed an open reading frame with extensive homology to bacterial Fur proteins. The cloned gene encodes a 16kDa protein that cross-reacts with a polyclonal anti-Escherichia coli Fur serum. The transcription start site was determined

Suvit Loprasert; Ratiboot Sallabhan; Wirongrong Whangsuk; Skorn Mongkolsuk

2000-01-01

153

Functional characterization of OXA-57, a class D beta-lactamase from Burkholderia pseudomallei.  

PubMed

Class D beta-lactamase OXA-57 was identified in a range of isolates of Burkholderia pseudomallei and Burkholderia thailandensis. Comparative kinetic analyses of wild-type and mutant forms of B. pseudomallei OXA-57 are reported. Implications of these data for beta-lactam resistance and the proposed role of Ser-104 in beta-lactam hydrolysis are discussed. PMID:15793160

Keith, Karen E; Oyston, Petra C; Crossett, Ben; Fairweather, Neil F; Titball, Richard W; Walsh, Timothy R; Brown, Katherine A

2005-04-01

154

ATP-binding cassette systems in Burkholderia pseudomallei and Burkholderia mallei  

Microsoft Academic Search

BACKGROUND: ATP binding cassette (ABC) systems are responsible for the import and export of a wide variety of molecules across cell membranes and comprise one of largest protein superfamilies found in prokarya, eukarya and archea. ABC systems play important roles in bacterial lifestyle, virulence and survival. In this study, an inventory of the ABC systems of Burkholderia pseudomallei strain K96243

David N Harland; Elie Dassa; Richard W Titball; Katherine A Brown; Helen S Atkins

2007-01-01

155

Comparison of DNA extraction kits for detection of Burkholderia pseudomallei in spiked human whole blood using real-time PCR.  

PubMed

Burkholderia pseudomallei, the etiologic agent of melioidosis, is endemic in northern Australia and Southeast Asia and can cause severe septicemia that may lead to death in 20% to 50% of cases. Rapid detection of B. pseudomallei infection is crucial for timely treatment of septic patients. This study evaluated seven commercially available DNA extraction kits to determine the relative recovery of B. pseudomallei DNA from spiked EDTA-containing human whole blood. The evaluation included three manual kits: the QIAamp DNA Mini kit, the QIAamp DNA Blood Mini kit, and the High Pure PCR Template Preparation kit; and four automated systems: the MagNAPure LC using the DNA Isolation Kit I, the MagNAPure Compact using the Nucleic Acid Isolation Kit I, and the QIAcube using the QIAamp DNA Mini kit and the QIAamp DNA Blood Mini kit. Detection of B. pseudomallei DNA extracted by each kit was performed using the B. pseudomallei specific type III secretion real-time PCR (TTS1) assay. Crossing threshold (C T ) values were used to compare the limit of detection and reproducibility of each kit. This study also compared the DNA concentrations and DNA purity yielded for each kit. The following kits consistently yielded DNA that produced a detectable signal from blood spiked with 5.5×10(4) colony forming units per mL: the High Pure PCR Template Preparation, QIAamp DNA Mini, MagNA Pure Compact, and the QIAcube running the QIAamp DNA Mini and QIAamp DNA Blood Mini kits. The High Pure PCR Template Preparation kit yielded the lowest limit of detection with spiked blood, but when this kit was used with blood from patients with confirmed cases of melioidosis, the bacteria was not reliably detected indicating blood may not be an optimal specimen. PMID:23460920

Podnecky, Nicole L; Elrod, Mindy G; Newton, Bruce R; Dauphin, Leslie A; Shi, Jianrong; Chawalchitiporn, Sutthinan; Baggett, Henry C; Hoffmaster, Alex R; Gee, Jay E

2013-01-01

156

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  

PubMed Central

Context: 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. Aim: We sought to evaluate detection of Burkholderia pseudomallei and Brucella spp. among patients presenting febrile illness. Material and Methods: Previously described polymerase chain reaction (PCR) assays for both pathogens were evaluated with Deoxyribonucleic acid extracts of buffy coat samples collected from 301 patients recruited prospectively. Data was not amenable to statistical analysis. Results: The PCR showed specific amplification and no non-specific amplification with heterologous Gram-negative bacilli. The lower limit of detection of the assay for B. pseudomallei was determined to be 1 colony-forming unit /mL and for Brucella it was 1.95 × 103 plasmids per microliter. Blood culture in automated blood culture system was negative for all the samples. This prospective study carried out in southern India for the first time. PCR for Brucella was positive in 1% of the patient samples whereas 0.3% was positive for B. pseudomallei. Conclusion: The finding of Brucella and Burkholderia infections in our populations leads us to suggest that tests for Brucella and B. pseudomallei should also form part of a diagnostic platform for patients with Pyrexia of unknown origin in tropical developing countries. PMID:22529625

Nandagopal, Balaji; Sankar, Sathish; Lingesan, Karthikeyan; Appu, KC; Sridharan, Gopalan; Gopinathan, Anilkumar

2012-01-01

157

Melioidosis from contaminated bore water and successful UV sterilization.  

PubMed

Two cases of melioidosis at a residence in rural northern Australia were linked to the unchlorinated domestic bore (automated well) water supply, which was found to have a high concentration of Burkholderia pseudomallei. Using multilocus sequence typing, clinical B. pseudomallei isolates from both cases were identical to an isolate from the bore water supply. A simple UV sterilizer reduced B. pseudomallei from the domestic water supply to undetectable levels. We have shown that UV treatment is highly effective for remediation of water contaminated with B. pseudomallei and recommend its consideration in households where individuals may be at heightened risk of contracting melioidosis. PMID:23751401

McRobb, Evan; Kaestli, Mirjam; Mayo, Mark; Price, Erin P; Sarovich, Derek S; Godoy, Daniel; Spratt, Brian G; Currie, Bart J

2013-08-01

158

Use of a Real-Time PCR TaqMan Assay for Rapid Identification and Differentiation of Burkholderia pseudomallei and Burkholderia mallei  

Microsoft Academic Search

A TaqMan allelic-discrimination assay designed around a synonymous single-nucleotide polymorphism was used to genotype Burkholderia pseudomallei and Burkholderia mallei isolates. The assay rapidly identifies and discriminates between these two highly pathogenic bacteria and does not cross-react with genetic near neigh- bors, such as Burkholderia thailandensis and Burkholderia cepacia. The intracellular, pathogenic bacteria Burkholderia pseudomallei and Burkholderia mallei are the causative

Jana M. U'Ren; Matthew N. Van Ert; James M. Schupp; W. Ryan Easterday; Tatum S. Simonson; Richard T. Okinaka; Talima Pearson; Paul Keim

2005-01-01

159

Melioidosis: a review.  

PubMed

The disease melioidosis, caused by the bacterium Burkholderia pseudomallei, remains an important and sometimes neglected cause of disease in tropical regions of Australia. Infection may present in myriad ways, and diagnosis often requires consideration of this organism prior to culture. Laboratory identification of B. pseudomallei requires specialised testing beyond that available in many routine diagnostic microbiology laboratories. For this reason, cases outside of the traditional endemic zone, often occurring years after initial exposure to the organism, may remain undiagnosed or are delayed in diagnosis. Furthermore, the high levels of intrinsic antimicrobial resistance associated with B. pseudomallei often render empirical therapies ineffective. Health professionals, particularly those in rural and remote areas of Australia, must consider melioidosis in their differential diagnoses and remain abreast of advances in the field of this important emerging disease. PMID:25359677

Foong, Y C; Tan, Michelle; Bradbury, Richard S

2014-01-01

160

Comparison of the protective effects of killed Burkholderia pseudomallei and CpG oligodeoxynucleotide against live challenge.  

PubMed

Melioidosis is a fatal disease caused by Burkholderia pseudomallei. Currently there is no vaccine available. Synthetic oligodeoxynucleotides with unmethylated CpG dinucleotide motifs (CpG ODN) can stimulate vertebrate immune cells and clear certain pathogens that are susceptible to a strong Th1 response. In our previous study, pretreatment with CpG ODN alone or CpG-ODN with cationic liposomes for 2-10 or 30 days before B. pseudomallei infection in mice conferred 80-100% protection. In the present study we investigated the protective effect of CpG-ODN together with heat-killed (HK) or paraformaldehyde-killed B. pseudomallei (PP). HK or PP were used to immunize BALB/c mice twice at 15-day intervals before intra-peritoneal challenge with 5LD50 of B. pseudomallei and observed for 30 days. We found that PP could significantly protect mice (60%) with an increased survival time (24.8±11.63 days) while in the HK and PBS groups, all infected mice died within 6 days. Although either CpG ODN or PP conferred significant protection, giving them in combination did not enhance it further. Serum IFN-? levels on day-5 (before challenge) of the PP and PP+CpG ODN groups were significantly higher than those of the PBS control group. The results further support the importance of IFN-? in host protection against B. pseudomallei and suggest further study on paraformaldehyde-killed bacteria as a component of a future B. pseudomallei vaccine. PMID:25223269

Puangpetch, Apichaya; Anderson, Robert; Huang, Yan Y; Saengsot, Rojana; Sermswan, Rasana W; Wongratanacheewin, Surasakdi

2014-10-14

161

Proteomic analysis of the Burkholderia pseudomallei type II secretome reveals hydrolytic enzymes, novel proteins, and the deubiquitinase TssM.  

PubMed

Burkholderia pseudomallei, the etiologic agent of melioidosis, is an opportunistic pathogen that harbors a wide array of secretion systems, including a type II secretion system (T2SS), three type III secretion systems (T3SS), and six type VI secretion systems (T6SS). The proteins exported by these systems provide B. pseudomallei with a growth advantage in vitro and in vivo, but relatively little is known about the full repertoire of exoproducts associated with each system. In this study, we constructed deletion mutations in gspD and gspE, T2SS genes encoding an outer membrane secretin and a cytoplasmic ATPase, respectively. The secretion profiles of B. pseudomallei MSHR668 and its T2SS mutants were noticeably different when analyzed by SDS-PAGE. We utilized liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify proteins present in the supernatants of B. pseudomallei MSHR668 and B. pseudomallei ?gspD grown in rich and minimal media. The MSHR668 supernatants contained 48 proteins that were either absent or substantially reduced in the supernatants of ?gspD strains. Many of these proteins were putative hydrolytic enzymes, including 12 proteases, two phospholipases, and a chitinase. Biochemical assays validated the LC-MS/MS results and demonstrated that the export of protease, phospholipase C, and chitinase activities is T2SS dependent. Previous studies had failed to identify the mechanism of secretion of TssM, a deubiquitinase that plays an integral role in regulating the innate immune response. Here we present evidence that TssM harbors an atypical signal sequence and that its secretion is mediated by the T2SS. This study provides the first in-depth characterization of the B. pseudomallei T2SS secretome. PMID:24866793

Burtnick, Mary N; Brett, Paul J; DeShazer, David

2014-08-01

162

BPSS1504, a cluster 1 type VI secretion gene, is involved in intracellular survival and virulence of Burkholderia pseudomallei.  

PubMed

Burkholderia pseudomallei is a Gram-negative rod and the causative agent of melioidosis, an emerging infectious disease of tropical and subtropical areas worldwide. B. pseudomallei harbors a remarkable number of virulence factors, including six type VI secretion systems (T6SS). Using our previously described plaque assay screening system, we identified a B. pseudomallei transposon mutant defective in the BPSS1504 gene that showed reduced plaque formation. The BPSS1504 locus is encoded within T6SS cluster 1 (T6SS1), which is known to be involved in the pathogenesis of B. pseudomallei in mammalian hosts. For further analysis, a B. pseudomallei BPSS1504 deletion (Bp?BPSS1504) mutant and complemented mutant strain were constructed. B. pseudomallei lacking the BPSS1504 gene was highly attenuated in BALB/c mice, whereas the in vivo virulence of the complemented mutant strain was fully restored to the wild-type level. The Bp?BPSS1504 mutant showed impaired intracellular replication and formation of multinucleated giant cells in macrophages compared with wild-type bacteria, whereas the induction of actin tail formation within host cells was not affected. These observations resembled the phenotype of a mutant lacking hcp1, which is an integral component of the T6SS1 apparatus and is associated with full functionality of the T6SS1. Transcriptional expression of the T6SS components vgrG, tssA, and hcp1, as well as the T6SS regulators virAG, bprC, and bsaN, was not dependent on BPSS1504 expression. However, secretion of Hcp1 was not detectable in the absence of BPSS1504. Thus, BPSS1504 seems to serve as a T6SS component that affects Hcp1 secretion and is therefore involved in the integrity of the T6SS1 apparatus. PMID:24595140

Hopf, Verena; Göhler, André; Eske-Pogodda, Kristin; Bast, Antje; Steinmetz, Ivo; Breitbach, Katrin

2014-05-01

163

Proteomic Analysis of the Burkholderia pseudomallei Type II Secretome Reveals Hydrolytic Enzymes, Novel Proteins, and the Deubiquitinase TssM  

PubMed Central

Burkholderia pseudomallei, the etiologic agent of melioidosis, is an opportunistic pathogen that harbors a wide array of secretion systems, including a type II secretion system (T2SS), three type III secretion systems (T3SS), and six type VI secretion systems (T6SS). The proteins exported by these systems provide B. pseudomallei with a growth advantage in vitro and in vivo, but relatively little is known about the full repertoire of exoproducts associated with each system. In this study, we constructed deletion mutations in gspD and gspE, T2SS genes encoding an outer membrane secretin and a cytoplasmic ATPase, respectively. The secretion profiles of B. pseudomallei MSHR668 and its T2SS mutants were noticeably different when analyzed by SDS-PAGE. We utilized liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify proteins present in the supernatants of B. pseudomallei MSHR668 and B. pseudomallei ?gspD grown in rich and minimal media. The MSHR668 supernatants contained 48 proteins that were either absent or substantially reduced in the supernatants of ?gspD strains. Many of these proteins were putative hydrolytic enzymes, including 12 proteases, two phospholipases, and a chitinase. Biochemical assays validated the LC-MS/MS results and demonstrated that the export of protease, phospholipase C, and chitinase activities is T2SS dependent. Previous studies had failed to identify the mechanism of secretion of TssM, a deubiquitinase that plays an integral role in regulating the innate immune response. Here we present evidence that TssM harbors an atypical signal sequence and that its secretion is mediated by the T2SS. This study provides the first in-depth characterization of the B. pseudomallei T2SS secretome. PMID:24866793

Burtnick, Mary N.; Brett, Paul J.

2014-01-01

164

Oropharyngeal Aspiration of Burkholderia mallei and Burkholderia pseudomallei in BALB/c Mice  

PubMed Central

Burkholderia mallei and Burkholderia pseudomallei are potentially lethal pathogens categorized as biothreat agents due, in part, to their ability to be disseminated via aerosol. There are no protective vaccines against these pathogens and treatment options are limited and cumbersome. Since disease severity is greatest when these agents are inhaled, efforts to develop pre- or post-exposure prophylaxis focus largely on inhalation models of infection. Here, we demonstrate a non-invasive and technically simple method for affecting the inhalational challenge of BALB/c mice with B. pseudomallei and B. mallei. In this model, two investigators utilized common laboratory tools such as forceps and a micropipette to conduct and characterize an effective and reproducible inhalational challenge of BALB/c mice with B. mallei and B. pseudomallei. Challenge by oropharyngeal aspiration resulted in acute disease. Additionally, 50% endpoints for B. pseudomallei K96243 and B. mallei ATCC 23344 were nearly identical to published aerosol challenge methods. Furthermore, the pathogens disseminated to all major organs typically targeted by these agents where they proliferated. The pro-inflammatory cytokine production in the proximal and peripheral fluids demonstrated a rapid and robust immune response comparable to previously described murine and human studies. These observations demonstrate that OA is a viable alternative to aerosol exposure. PMID:25503969

Schully, Kevin L.; Bell, Matthew G.; Ward, Jerrold M.; Keane-Myers, Andrea M.

2014-01-01

165

Clinical, environmental, and serologic surveillance studies of melioidosis in Gabon, 2012-2013.  

PubMed

Burkholderia pseudomallei, an environmental gram-negative bacillus, is the causative agent of melioidosis and a bio-threat agent. Reports of B. pseudomallei isolation from soil and animals in East and West Africa suggest that melioidosis might be more widely distributed than previously thought. Because it has been found in equatorial areas with tropical climates, we hypothesized that B. pseudomallei could exist in Gabon. During 2012-2013, we conducted a seroprevalance study in which we set up microbiology facilities at a large clinical referral center and prospectively screened all febrile patients by conducting blood cultures and testing for B. pseudomallei and related species; we also determined whether B. pseudomallei could be isolated from soil. We discovered a novel B. pseudomallei sequence type that caused lethal septic shock and identified B. pseudomallei and B. thailandensis in the environment. Our data suggest that melioidosis is emerging in Central Africa but is unrecognized because of the lack of diagnostic microbiology facilities. PMID:25530077

Wiersinga, W Joost; Birnie, Emma; Weehuizen, Tassili A F; Alabi, Abraham S; Huson, Michaëla A M; In 't Veld, Robert A G Huis; Mabala, Harry K; Adzoda, Gregoire K; Raczynski-Henk, Yannick; Esen, Meral; Lell, Bertrand; Kremsner, Peter G; Visser, Caroline E; Wuthiekanun, Vanaporn; Peacock, Sharon J; van der Ende, Arie; Limmathurotsakul, Direk; Grobusch, Martin P

2015-01-01

166

Clinical, Environmental, and Serologic Surveillance Studies of Melioidosis in Gabon, 2012–2013  

PubMed Central

Burkholderia pseudomallei, an environmental gram-negative bacillus, is the causative agent of melioidosis and a bio-threat agent. Reports of B. pseudomallei isolation from soil and animals in East and West Africa suggest that melioidosis might be more widely distributed than previously thought. Because it has been found in equatorial areas with tropical climates, we hypothesized that B. pseudomallei could exist in Gabon. During 2012–2013, we conducted a seroprevalance study in which we set up microbiology facilities at a large clinical referral center and prospectively screened all febrile patients by conducting blood cultures and testing for B. pseudomallei and related species; we also determined whether B. pseudomallei could be isolated from soil. We discovered a novel B. pseudomallei sequence type that caused lethal septic shock and identified B. pseudomallei and B. thailandensis in the environment. Our data suggest that melioidosis is emerging in Central Africa but is unrecognized because of the lack of diagnostic microbiology facilities. PMID:25530077

Birnie, Emma; Weehuizen, Tassili A.F.; Alabi, Abraham S.; Huson, Michaëla A.M.; in ’t Veld, Robert A. G. Huis; Mabala, Harry K.; Adzoda, Gregoire K.; Raczynski-Henk, Yannick; Esen, Meral; Lell, Bertrand; Kremsner, Peter G.; Visser, Caroline E.; Wuthiekanun, Vanaporn; Peacock, Sharon J.; van der Ende, Arie; Limmathurotsakul, Direk; Grobusch, Martin P.

2015-01-01

167

Association of melioidosis incidence with rainfall and humidity, singapore, 2003-2012.  

PubMed

Soil has been considered the natural reservoir for the bacterium Burkholderia pseudomallei, which causes melioidosis. We examined 550 melioidosis cases that occurred during a 10-year period in the highly urbanized city of Singapore, where soil exposure is rare, and found that rainfall and humidity levels were associated with disease incidence. PMID:25531547

Liu, Xiang; Pang, Long; Sim, Siew Hoon; Goh, Kee Tai; Ravikumar, Sharada; Win, Mar Soe; Tan, Gladys; Cook, Alex Richard; Fisher, Dale; Chai, Louis Yi Ann

2015-01-01

168

Association of Melioidosis Incidence with Rainfall and Humidity, Singapore, 2003–2012  

PubMed Central

Soil has been considered the natural reservoir for the bacterium Burkholderia pseudomallei, which causes melioidosis. We examined 550 melioidosis cases that occurred during a 10-year period in the highly urbanized city of Singapore, where soil exposure is rare, and found that rainfall and humidity levels were associated with disease incidence. PMID:25531547

Liu, Xiang; Pang, Long; Sim, Siew Hoon; Goh, Kee Tai; Ravikumar, Sharada; Win, Mar Soe; Tan, Gladys; Cook, Alex Richard; Fisher, Dale

2015-01-01

169

Membrane-active mechanism of LFchimera against Burkholderia pseudomallei and Burkholderia thailandensis.  

PubMed

LFchimera, a construct combining two antimicrobial domains of bovine lactoferrin, lactoferrampin265-284 and lactoferricin17-30, possesses strong bactericidal activity. As yet, no experimental evidence was presented to evaluate the mechanisms of LFchimera against Burkholderia isolates. In this study we analyzed the killing activity of LFchimera on the category B pathogen Burkholderia pseudomallei in comparison to the lesser virulent Burkholderia thailandensis often used as a model for the highly virulent B. pseudomallei. Killing kinetics showed that B. thailandensis E264 was more susceptible for LFchimera than B. pseudomallei 1026b. Interestingly the bactericidal activity of LFchimera appeared highly pH dependent; B. thailandensis killing was completely abolished at and below pH 6.4. FITC-labeled LFchimera caused a rapid accumulation within 15 min in the cytoplasm of both bacterial species. Moreover, freeze-fracture electron microscopy demonstrated extreme effects on the membrane morphology of both bacterial species within 1 h of incubation, accompanied by altered membrane permeability monitored as leakage of nucleotides. These data indicate that the mechanism of action of LFchimera is similar for both species and encompasses disruption of the plasma membrane and subsequently leakage of intracellular nucleotides leading to cell dead. PMID:24961697

Kanthawong, Sakawrat; Puknun, Aekkalak; Bolscher, Jan G M; Nazmi, Kamran; van Marle, Jan; de Soet, Johannes J; Veerman, Enno C I; Wongratanacheewin, Surasakdi; Taweechaisupapong, Suwimol

2014-10-01

170

Melioidosis as a consequence of sporting activity.  

PubMed

In the tropical city of Darwin, Northern Territory, Australia, dry season soil sampling cultured Burkholderia pseudomallei from 7 (70%) of 10 sports fields. However, during the 23 years of the Darwin Prospective Melioidosis Study, only 5 (0.6%) of 785 melioidosis cases have been attributed to infection from sports fields. In one soccer player with cutaneous melioidosis, B. pseudomallei cultured from the player was identical by multilocus sequence typing and multilocus variable-number tandem repeat analysis with an isolate recovered from soil at the location on the sports field where he was injured. Melioidosis is uncommon in otherwise healthy sports persons in melioidosis-endemic regions but still needs consideration in persons with abrasion injuries that involve contact with soil. PMID:23732257

Hill, Audrey A; Mayo, Mark; Kaestli, Mirjam; Price, Erin P; Richardson, Leisha J; Godoy, Daniel; Spratt, Brian G; Currie, Bart J

2013-08-01

171

Burkholderia mallei and Burkholderia pseudomallei stimulate differential inflammatory responses from human alveolar type II cells (ATII) and macrophages  

PubMed Central

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 macrophages (MDM). We hypothesized that because BP and BM induce different disease outcomes, each pathogen would induce distinct, unique host immune responses from resident pulmonary cells. Our findings showed that BP adhered readily to ATII cells compared to BM. BP, but not BM, was rapidly internalized by macrophages where it replicated to high numbers. Further, BP-induced significantly higher levels of pro-inflammatory cytokine secretion from ATII cells (IL-6, IL-8) and macrophages (IL-6, TNF?) at 6 h post-infection compared to BM (p < 0.05). Interestingly, BM-induced the anti-inflammatory cytokine, IL-10, in ATII cells and macrophages at 6 h post-infection, with delayed induction of inflammatory cytokines at 24 h post-infection. Because BP is flagellated and produces LPS, we confirmed that it stimulated both Toll-like receptor (TLR) 4 and TLR5 via NF-?b activation while the non-flagellated BM stimulated only TLR4. These data show the differences in BP and BM pathogenicity in the lung when infecting human ATII cells and macrophages and demonstrate the ability of these pathogens to elicit distinct immune responses from resident lung cells which may open new targets for therapeutic intervention to fight against these pathogens. PMID:23293773

Lu, Richard; Popov, Vsevolod; Patel, Jignesh; Eaves-Pyles, Tonyia

2012-01-01

172

Induction of Mouse Melioidosis with Meningitis by CD11b+ Phagocytic Cells Harboring Intracellular B. pseudomallei as a Trojan Horse  

PubMed Central

Background Approximately 3–5% of patients with melioidosis manifest CNS symptoms; however, the clinical data regarding neurological melioidosis are limited. Methods and Findings We established a mouse model of melioidosis with meningitis characterized by neutrophil infiltration into the meninges histologically and B. pseudomallei in the cerebrospinal fluid (CSF) by bacteriological culturing methods. As the disease progresses, the bacteria successively colonize the spleen, liver, bone marrow (BM) and brain and invade splenic and BM cells by days 2 and 6 post-infection, respectively. The predominant cell types intracellularly infected with B. pseudomallei were splenic and BM CD11b+ populations. The CD11b+Ly6Chigh inflamed monocytes, CD11b+Ly6Clow resident monocytes, CD11b+Ly6G+ neutrophils, CD11b+F4/80+ macrophages and CD11b+CD19+ B cells were expanded in the spleen and BM during the progression of melioidosis. After adoptive transfer of CD11b populations harboring B. pseudomallei, the infected CD11b+ cells induced bacterial colonization in the brain, whereas CD11b? cells only partially induced colonization; extracellular (free) B. pseudomallei were unable to colonize the brain. CD62L (selectin) was absent on splenic CD11b+ cells on day 4 but was expressed on day 10 post-infection. Adoptive transfer of CD11b+ cells expressing CD62L (harvested on day 10 post-infection) resulted in meningitis in the recipients, but transfer of CD11b+ CD62L-negative cells did not. Conclusions/Significance We suggest that B. pseudomallei-infected CD11b+ selectin-expressing cells act as a Trojan horse and are able to transmigrate across endothelial cells, resulting in melioidosis with meningitis. PMID:23951382

Liu, Pei-Ju; Chen, Yao-Shen; Lin, Hsi-Hsu; Ni, Wei-Feng; Hsieh, Tsung-Han; Chen, Hsu-Tzu; Chen, Ya-Lei

2013-01-01

173

Disarming Burkholderia pseudomallei: Structural and Functional Characterization of a Disulfide Oxidoreductase (DsbA) Required for Virulence In Vivo  

PubMed Central

Abstract Aims: The intracellular pathogen Burkholderia pseudomallei causes the disease melioidosis, a major source of morbidity and mortality in southeast Asia and northern Australia. The need to develop novel antimicrobials is compounded by the absence of a licensed vaccine and the bacterium's resistance to multiple antibiotics. In a number of clinically relevant Gram-negative pathogens, DsbA is the primary disulfide oxidoreductase responsible for catalyzing the formation of disulfide bonds in secreted and membrane-associated proteins. In this study, a putative B. pseudomallei dsbA gene was evaluated functionally and structurally and its contribution to infection assessed. Results: Biochemical studies confirmed the dsbA gene encodes a protein disulfide oxidoreductase. A dsbA deletion strain of B. pseudomallei was attenuated in both macrophages and a BALB/c mouse model of infection and displayed pleiotropic phenotypes that included defects in both secretion and motility. The 1.9 Å resolution crystal structure of BpsDsbA revealed differences from the classic member of this family Escherichia coli DsbA, in particular within the region surrounding the active site disulfide where EcDsbA engages with its partner protein E. coli DsbB, indicating that the interaction of BpsDsbA with its proposed partner BpsDsbB may be distinct from that of EcDsbA-EcDsbB. Innovation: This study has characterized BpsDsbA biochemically and structurally and determined that it is required for virulence of B. pseudomallei. Conclusion: These data establish a critical role for BpsDsbA in B. pseudomallei infection, which in combination with our structural characterization of BpsDsbA will facilitate the future development of rationally designed inhibitors against this drug-resistant organism. Antioxid. Redox Signal. 20, 606–617. PMID:23901809

McMahon, Róisín M.; Marshall, Laura E.; Halili, Maria; Furlong, Emily; Tay, Stephanie; Sarkar-Tyson, Mitali

2014-01-01

174

Structural characterization of Burkholderia pseudomallei adenylate kinase (Adk): Profound asymmetry in the crystal structure of the 'open' state  

SciTech Connect

In all organisms adenylate kinases (Adks) play a vital role in cellular energy metabolism and nucleic acid synthesis. Due to differences in catalytic properties between the Adks found in prokaryotes and in the cytoplasm of eukaryotes, there is interest in targeting this enzyme for new drug therapies against infectious bacterial agents. Here we report the 2.1 {angstrom} resolution crystal structure for the 220-residue Adk from Burkholderia pseudomallei (BpAdk), the etiological agent responsible for the infectious disease melioidosis. The general structure of apo BpAdk is similar to other Adk structures, composed of a CORE subdomain with peripheral ATP-binding (ATP{sub bd}) and LID subdomains. The two molecules in the asymmetric unit have significantly different conformations, with a backbone RMSD of 1.46 {angstrom}. These two BpAdk conformations may represent 'open' Adk sub-states along the preferential pathway to the 'closed' substrate-bound state.

Buchko, G.W.; Robinson, H.; Abendroth, J.; Staker, B. L.; Myler, P. J.

2010-04-16

175

Leveraging structure determination with fragment screening for infectious disease drug targets: MECP synthase from Burkholderia pseudomallei  

SciTech Connect

As part of the Seattle Structural Genomics Center for Infectious Disease, we seek to enhance structural genomics with ligand-bound structure data which can serve as a blueprint for structure-based drug design. We have adapted fragment-based screening methods to our structural genomics pipeline to generate multiple ligand-bound structures of high priority drug targets from pathogenic organisms. In this study, we report fragment screening methods and structure determination results for 2C-methyl-D-erythritol-2,4-cyclo-diphosphate (MECP) synthase from Burkholderia pseudomallei, the gram-negative bacterium which causes melioidosis. Screening by nuclear magnetic resonance spectroscopy as well as crystal soaking followed by X-ray diffraction led to the identification of several small molecules which bind this enzyme in a critical metabolic pathway. A series of complex structures obtained with screening hits reveal distinct binding pockets and a range of small molecules which form complexes with the target. Additional soaks with these compounds further demonstrate a subset of fragments to only bind the protein when present in specific combinations. This ensemble of fragment-bound complexes illuminates several characteristics of MECP synthase, including a previously unknown binding surface external to the catalytic active site. These ligand-bound structures now serve to guide medicinal chemists and structural biologists in rational design of novel inhibitors for this enzyme.

Begley, Darren W.; Hartley, Robert C.; Davies, Douglas R.; Edwards, Thomas E.; Leonard, Jess T.; Abendroth, Jan; Burris, Courtney A.; Bhandari, Janhavi; Myler, Peter J.; Staker, Bart L.; Stewart, Lance J. (UWASH); (Emerald)

2011-09-28

176

Burkholderia pseudomallei sequencing identifies genomic clades with distinct recombination, accessory, and epigenetic profiles.  

PubMed

Burkholderia pseudomallei (Bp) is the causative agent of the infectious disease melioidosis. To investigate population diversity, recombination, and horizontal gene transfer in closely related Bp isolates, we performed whole-genome sequencing (WGS) on 106 clinical, animal, and environmental strains from a restricted Asian locale. Whole-genome phylogenies resolved multiple genomic clades of Bp, largely congruent with multilocus sequence typing (MLST). We discovered widespread recombination in the Bp core genome, involving hundreds of regions associated with multiple haplotypes. Highly recombinant regions exhibited functional enrichments that may contribute to virulence. We observed clade-specific patterns of recombination and accessory gene exchange, and provide evidence that this is likely due to ongoing recombination between clade members. Reciprocally, interclade exchanges were rarely observed, suggesting mechanisms restricting gene flow between clades. Interrogation of accessory elements revealed that each clade harbored a distinct complement of restriction-modification (RM) systems, predicted to cause clade-specific patterns of DNA methylation. Using methylome sequencing, we confirmed that representative strains from separate clades indeed exhibit distinct methylation profiles. Finally, using an E. coli system, we demonstrate that Bp RM systems can inhibit uptake of non-self DNA. Our data suggest that RM systems borne on mobile elements, besides preventing foreign DNA invasion, may also contribute to limiting exchanges of genetic material between individuals of the same species. Genomic clades may thus represent functional units of genetic isolation in Bp, modulating intraspecies genetic diversity. PMID:25236617

Nandi, Tannistha; Holden, Mathew T G; Didelot, Xavier; Mehershahi, Kurosh; Boddey, Justin A; Beacham, Ifor; Peak, Ian; Harting, John; Baybayan, Primo; Guo, Yan; Wang, Susana; How, Lee Chee; Sim, Bernice; Essex-Lopresti, Angela; Sarkar-Tyson, Mitali; Nelson, Michelle; Smither, Sophie; Ong, Catherine; Aw, Lay Tin; Hoon, Chua Hui; Michell, Stephen; Studholme, David J; Titball, Richard; Chen, Swaine L; Parkhill, Julian; Tan, Patrick

2015-01-01

177

Two fatal cases of melioidosis on the Thai-Myanmar border  

PubMed Central

Melioidosis is endemic in areas of Southeast Asia, however, there are no published reports from the Thai-Myanmar border. We report the first two documented cases of fatal melioidosis in this region. This is of great public health importance and highlights the need to both increase clinical awareness of melioidosis on the Thai-Myanmar border, and to assess the true burden of disease in the area through improved case detection and Burkholderia pseudomallei prevalence studies. PMID:24715973

Nosten, François

2014-01-01

178

Radiological manifestations of melioidosis.  

PubMed

Melioidosis is a serious infection that is associated with high mortality. It is due to a Gram-negative bacterium, Burkholderia pseudomallei which is an environmental saprophyte found in wet soils. Melioidosis is endemic to northern Australia and the Southeast Asia. However, there is now increasing number of reports of imported cases to regions where this infection has not been previously encountered. Almost any organ can be affected. Like many other conditions, radiological imaging is an integral part of the diagnostic workup of melioidosis. Awareness of the various radiological manifestations can help direct appropriate investigations to achieve early diagnosis and the initiation of appropriate treatment. Generally, there are no known characteristic features on imaging that can specifically differentiate melioidosis from other infections. However, the "honeycomb" appearance has been described to be characteristic for large melioidosis liver abscesses. Simultaneous involvement of various organs is also characteristics. To date, there are few data available on the radiological manifestations of melioidosis. The present pictorial essay describes melioidosis affecting the various organs. PMID:20103424

Lim, K S; Chong, V H

2010-01-01

179

Evaluation of the Remel RapID NF plus rapid biochemical method for identification of Burkholderia pseudomallei.  

PubMed

Typical methods for the identification of Burkholderia pseudomallei colonies produce results in 18 h. The Remel RapID NF Plus kit produces results in 4 h. We used the kit for 190 stored B. pseudomallei isolates and correctly identified 189 of them. This kit produces consistent results for known B. pseudomallei isolates. PMID:24671779

Maloney, Samuel; Engler, Cathy; Norton, Robert

2014-06-01

180

Role of Inducible Nitric Oxide Synthase and NADPH Oxidase in Early Control of Burkholderia pseudomallei Infection in Mice  

Microsoft Academic Search

Infection with the soil bacterium Burkholderia pseudomallei can result in a variety of clinical outcomes, including asymptomatic infection. The initial immune defense mechanisms which might contribute to the various outcomes after environmental contact with B. pseudomallei are largely unknown. We have previously shown that relatively resistant C57BL\\/6 mice can restrict bacterial B. pseudomallei growth more efficiently within 1 day after

Katrin Breitbach; Sonja Klocke; Thomas Tschernig; Nico van Rooijen; Ulrich Baumann; Ivo Steinmetz

2006-01-01

181

Incidence, risk factors and clinical epidemiology of melioidosis: a complex socio-ecological emerging infectious disease in the Alor Setar region of Kedah, Malaysia  

Microsoft Academic Search

BACKGROUND: Melioidosis, a severe and fatal infectious disease caused by Burkholderia pseudomallei, is believed to an emerging global threat. However, data on the natural history, risk factors, and geographic epidemiology of the disease are still limited. METHODS: We undertook a retrospective analysis of 145 confirmed cases extracted from a hospital-based Melioidosis Registry set up from 2005 in Hospital Sultanah Bahiyah,

Muhammad RA Hassan; Subhada P Pani; Ng P Peng; Kirtanaa Voralu; Natesan Vijayalakshmi; Ranjith Mehanderkar; Norasmidar A Aziz; Edwin Michael

2010-01-01

182

Characterization of an autotransporter adhesin protein shared by Burkholderia mallei and Burkholderia pseudomallei  

PubMed Central

Background Autotransporters form a large family of outer membrane proteins specifying diverse biological traits of Gram-negative bacteria. In this study, we report the identification and characterization of a novel autotransporter gene product of Burkholderia mallei (locus tag BMA1027 in strain ATCC 23344). Results Database searches identified the gene in at least seven B. mallei isolates and the encoded proteins were found to be 84% identical. Inactivation of the gene encoding the autotransporter in the genome of strain ATCC 23344 substantially reduces adherence to monolayers of HEp-2 laryngeal cells and A549 type II pneumocytes, as well as to cultures of normal human bronchial epithelium (NHBE). Consistent with these findings, expression of the autotransporter on the surface of recombinant E. coli bacteria increases adherence to these cell types by 5–7 fold. The gene specifying the autotransporter was identified in the genome of 29 B. pseudomallei isolates and disruption of the gene in strain DD503 reduced adherence to NHBE cultures by 61%. Unlike B. mallei, the mutation did not impair binding of B. pseudomallei to A549 or HEp-2 cells. Analysis of sera from mice infected via the aerosol route with B. mallei and B. pseudomallei revealed that animals inoculated with as few as 10 organisms produce antibodies against the autotransporter, therefore indicating expression in vivo. Conclusions Our data demonstrate that we have identified an autotransporter protein common to the pathogenic species B. mallei and B. pseudomallei which mediates adherence to respiratory epithelial cells and is expressed in vivo during the course of aerosol infection. PMID:24731253

2014-01-01

183

The epidemiology of melioidosis in the Balimo region of Papua New Guinea.  

PubMed

The distribution of Burkholderia pseudomallei was determined in soil collected from a rural district in Papua New Guinea (PNG) where melioidosis had recently been described, predominately affecting children. In 274 samples, 2.6% tested culture-positive for B. pseudomallei. Pulsed-field gel electrophoresis using SpeI digests and rapid polymorphic DNA PCR with five primers demonstrated a single clone amongst clinical isolates and isolates cultured from the environment that was commonly used by children from whom the clinical isolates were derived. We concluded that individuals in this region most probably acquired the organism through close contact with the environment at these sites. Burkholderia thailandensis, a closely related Burkholderia sp. was isolated from 5.5% of samples tested, an observation similar to that of melioidosis-endemic areas in Thailand. This is the first report of an environmental reservoir for melioidosis in PNG and confirms the Balimo district in PNG as melioidosis endemic. PMID:17714600

Warner, J M; Pelowa, D B; Gal, D; Rai, G; Mayo, M; Currie, B J; Govan, B; Skerratt, L F; Hirst, R G

2008-07-01

184

Immunostimulatory CpG Oligodeoxynucleotide Confers Protection in a Murine Model of Infection with Burkholderia pseudomallei  

Microsoft Academic Search

Although CpG oligodeoxynucleotides (CpG ODNs) are known to enhance resistance against infection in a number of animal models, little is known about the CpG-induced protection against acute fatal sepsis such as that associated with the highly virulent bacterium Burkholderia pseudomallei. We previously demonstrated in an in vitro study that immunostimulatory CpG ODN 1826 enhances phagocytosis of B. pseudomallei and induces

Surasakdi Wongratanacheewin; Wannapa Kespichayawattana; Pakamas Intachote; Sathit Pichyangkul; Rasana W. Sermswan; Arthur M. Krieg; Stitaya Sirisinha

2004-01-01

185

Rapid Identification of Burkholderia pseudomallei by Latex Agglutination Based on an Exopolysaccharide-Specific Monoclonal Antibody  

Microsoft Academic Search

We recently identified a constitutively expressed exopolysaccharide of Burkholderia pseudomallei which is composed of a unique linear tetrasaccharide repeating unit consisting of three galactose residues and one 3-deoxy-D-manno-2-octulosonic acid residue. In this study we developed a latex agglutination test based on monoclonal antibody 3015, which is specific for this exopolysaccharide, and evaluated this test for rapid identification of B. pseudomallei

I. STEINMETZ; A. REGANZEROWSKI; B. BRENNEKE; S. HAUSSLER; A. SIMPSON; N. J. WHITE

1999-01-01

186

Extended Loop Region of Hcp1 is Critical for the Assembly and Function of Type VI Secretion System in Burkholderia pseudomallei.  

PubMed

The Type VI Secretion System cluster 1 (T6SS1) is essential for the pathogenesis of Burkholderia pseudomallei, the causative agent of melioidosis, a disease endemic in the tropics. Inside host cells, B. pseudomallei escapes into the cytosol and through T6SS1, induces multinucleated giant cell (MNGC) formation that is thought to be important for bacterial cell to cell spread. The hemolysin-coregulated protein (Hcp) is both a T6SS substrate, as well as postulated to form part of the T6SS secretion tube. Our structural study reveals that Hcp1 forms hexameric rings similar to the other Hcp homologs but has an extended loop (Asp40-Arg56) that deviates significantly in position compared to other Hcp structures and may act as a key contact point between adjacent hexameric rings. When two residues within the loop were mutated, the mutant proteins were unable to stack as dodecamers, suggesting defective tube assembly. Moreover, infection with a bacterial mutant containing in situ substitution of these hcp1 residues abolishes Hcp1 secretion inside infected cells and MNGC formation. We further show that Hcp has the ability to preferentially bind to the surface of antigen-presenting cells, which may contribute to its immunogenicity in inducing high titers of antibodies seen in melioidosis patients. PMID:25648885

Lim, Yan Ting; Jobichen, Chacko; Wong, Jocelyn; Limmathurotsakul, Direk; Li, Shaowei; Chen, Yahua; Raida, Manfred; Srinivasan, Nalini; MacAry, Paul Anthony; Sivaraman, J; Gan, Yunn-Hwen

2015-01-01

187

Genetic Tools for Select-Agent-Compliant Manipulation of Burkholderia pseudomallei  

Microsoft Academic Search

Because of Burkholderia pseudomallei's classification as a select agent in the United States, genetic manip- ulation of this bacterium is strictly regulated. Only a few antibiotic selection markers, including gentamicin, kanamycin, and zeocin, are currently approved for use with this bacterium, but wild-type strains are highly resistant to these antibiotics. To facilitate routine genetic manipulations of wild-type strains, several new

Kyoung-Hee Choi; Takehiko Mima; Yveth Casart; Drew Rholl; Ayush Kumar; Ifor R. Beacham; Herbert P. Schweizer

2008-01-01

188

Melioidosis: molecular aspects of pathogenesis.  

PubMed

Burkholderia pseudomallei is a gram-negative bacterium that causes melioidosis, a multifaceted disease that is highly endemic in southeast Asia and northern Australia. This facultative intracellular pathogen possesses a large genome that encodes a wide array of virulence factors that promote survival in vivo by manipulating host cell processes and disarming elements of the host immune system. Antigens and systems that play key roles in B. pseudomallei virulence include capsular polysaccharide, lipopolysaccharide, adhesins, specialized secretion systems, actin-based motility and various secreted factors. This review provides an overview of the current and steadily expanding knowledge regarding the molecular mechanisms used by this organism to survive within a host and their contribution to the pathogenesis of melioidosis. PMID:25312349

Stone, Joshua K; DeShazer, David; Brett, Paul J; Burtnick, Mary N

2014-12-01

189

Effect of oral N-acetyl cysteine supplementation in type 2 diabetic patients on intracellular glutathione content and innate immune responses to Burkholderia pseudomallei.  

PubMed

Type 2 diabetic patients have increased susceptibility to melioidosis, an infectious disease caused by Burkholderia pseudomallei. We had previously shown that peripheral blood mononuclear cells (PBMCs) from diabetic patients with poor glycemic control had a defective IL-12 and IFN? response to B. pseudomallei infection, resulting in poor intracellular bacterial control. The impaired IL-12 response was due to glutathione (GSH) deficiency characterized by a low reduced to oxidized glutathione ratio (GSH ratio) and could be restored by the addition of reduced GSH to the infected cells. Our goal is to determine whether N-acetyl cysteine (NAC, a GSH pro-drug) supplementation in diabetic patients could improve their immune control of B. pseudomallei. Type 2 diabetic patients with poor glycemic control were given oral supplementation of NAC for six weeks at 1200 mg daily. Their PBMCs and subsets of immune cells showed a significant increase in free GSH concentration. However, the GSH ratio, IL-12 and IFN? production, and intracellular bacterial killing upon ex-vivo infection did not improve. Thus, oral NAC supplementation in diabetic patients is sufficient to increase intracellular GSH content in blood cells. However, modulating the free GSH content is not sufficient to improve infection outcome as it is the GSH ratio that regulates the IL-12 response in monocytes. PMID:25088507

Gamage, Akshamal M; Lee, Kok Onn; Gan, Yunn-Hwen

2014-08-01

190

Development and evaluation of a real-time PCR assay targeting the type III secretion system of Burkholderia pseudomallei  

Microsoft Academic Search

Here we report on the development of a discriminatory real-time assay for the rapid identification of Burkholderia pseudomallei isolates and the evaluation of this assay for sensitivity against related species and detection in spiked human blood samples. The assay targets a 115-base-pair region within orf2 of the B. pseudomallei type III secretion system gene cluster and distinguishes B. pseudomallei from

Ryan T. Novak; Mindy B. Glass; Jay E. Gee; Daniel Gal; Mark J. Mayo; Bart J. Currie; Patricia P. Wilkins

2006-01-01

191

Genetic and Transcriptional Analysis of the Siderophore Malleobactin Biosynthesis and Transport Genes in the Human Pathogen Burkholderia pseudomallei K96243  

PubMed Central

Burkholderia pseudomallei is a gram-negative facultative intracellular pathogen that causes melioidosis, an invasive disease of humans and animals. To address the response of this bacterium to iron-limiting conditions, we first performed a global transcriptional analysis of RNA extracted from bacteria grown under iron-limiting and iron-rich conditions by microarrays. We focused our study on those open reading frames (ORFs) induced under iron limitation, which encoded predicted proteins that could be involved in the biosynthesis and uptake of the siderophore malleobactin. We purified this siderophore and determined that it consisted of at least three compounds with different molecular weights. We demonstrated that ORFs BPSL1776 and BPSL1774, designated mbaA and mbaF, respectively, are involved in the biosynthesis of malleobactin, while BPSL1775, named fmtA, is involved in its transport. These genes are in an operon with two other ORFs (mbaJ and mbaI) whose transcription is under the control of MbaS, a protein that belongs to the extracytoplasmic function sigma factors. Interestingly, the transcription of the mbaA, fmtA, and mbaS genes is not controlled by the availability of the siderophore malleobactin. PMID:16452439

Alice, Alejandro F.; López, Claudia S.; Lowe, Carolyn A.; Ledesma, Maria A.; Crosa, Jorge H.

2006-01-01

192

Mycotic aneurysm caused by Burkholderia pseudomallei in a previously healthy returning traveller.  

PubMed

Burkholderia pseudomallei is a common cause of serious, difficult to treat infections in South-East Asia and Northern Australia, but is a rare imported pathogen in the USA and Europe. We report a case of a patient with a mycotic aneurysm caused by B. pseudomallei in a previously healthy returning traveller. The patient presented with 4 weeks of abdominal pain and intermittent fever after a brief vacation in Thailand. The aneurysm was excised and replaced by an autologous deep vein graft, and the patient was treated for 6 months with antibiotics adjusted according to postoperative renal impairment. Twenty-four months after surgery the patient is well and without relapse. PMID:25246454

Bodilsen, Jacob; Vammen, Sten; Fuursted, Kurt; Hjort, Ulla

2014-01-01

193

Melioidosis: evolving concepts in epidemiology, pathogenesis, and treatment.  

PubMed

Infection with Burkholderia pseudomallei can result in asymptomatic seroconversion, a single skin lesion that may or may not heal spontaneously, a pneumonia which can be subacute or chronic and mimic tuberculosis or rapidly progressive resulting in fatal overwhelming sepsis. Latency with subsequent activation of disease is well recognized, but very uncommon. Melioidosis also has a myriad of other clinical presentations and diagnosis is often delayed because of this and because of difficulties with laboratory diagnosis and lack of recognition outside melioidosis-endemic regions. The perception of B. pseudomallei as a top tier biothreat agent has driven large funding for research, yet resources for diagnosis and therapy of melioidosis in many endemic locations remain extremely limited, with mortality as high as 50% in comparison to around 10% in regions where state-of-the-art intensive care therapy for sepsis is available. Fatal melioidosis is extremely unlikely from natural infection in a healthy person, provided the diagnosis is made early, ceftazidime or meropenem is commenced and intensive care therapy is available. While biothreat research is directed toward potential aerosol exposure to B. pseudomallei, the overall proportion of melioidosis cases resulting from inhalation rather than from percutaneous inoculation remains entirely uncertain, although the epidemiology supports a shift to inhalation during severe weather events such as cyclones and typhoons. What makes B. pseudomallei such a dangerous organism for patients with diabetes and other selective risk factors remains unclear, but microbial genome-wide association studies linking clinical aspects of melioidosis cases to nonubiquitous or polymorphic B. pseudomallei genes or genomic islands are beginning to uncover specific virulence signatures. Finally, what also remains uncertain is the global phylogeography of B. pseudomallei and whether melioidosis is spreading beyond historical locations or is just being unmasked in Africa and the Americas by better recognition and increased surveillance. PMID:25643275

Currie, Bart J

2015-02-01

194

Genomic transcriptional profiling identifies a candidate blood biomarker signature for the diagnosis of septicemic melioidosis  

Microsoft Academic Search

BACKGROUND: Melioidosis is a severe infectious disease caused by Burkholderia pseudomallei, a Gram-negative bacillus classified by the National Institute of Allergy and Infectious Diseases (NIAID) as a category B priority agent. Septicemia is the most common presentation of the disease with a 40% mortality rate even with appropriate treatments. Better diagnostic tests are therefore needed to improve therapeutic efficacy and

Rungnapa Pankla; Surachat Buddhisa; Matthew Berry; Derek M Blankenship; Gregory J Bancroft; Jacques Banchereau; Ganjana Lertmemongkolchai; Damien Chaussabel

2009-01-01

195

Paediatric melioidosis with septic shock in a previously-well child.  

PubMed

We present a previously-healthy 12-year old girl from a rural community and who was admitted to a district general hospital in Malaysia with coagulopathy and septic shock. Despite receiving intensive care, she succumbed to her illness. Blood cultures grew Burkholderia pseudomallei. Melioidosis is an unusual cause of paediatric Gram-negative sepsis among children in Malaysia. PMID:17384864

Kandasamy, Y; Somasundaram, P

2007-04-01

196

Interim report on updated microarray probes for the LLNL Burkholderia pseudomallei SNP array  

SciTech Connect

The overall goal of this project is to forensically characterize 100 unknown Burkholderia isolates in the US-Australia collaboration. We will identify genome-wide single nucleotide polymorphisms (SNPs) from B. pseudomallei and near neighbor species including B. mallei, B. thailandensis and B. oklahomensis. We will design microarray probes to detect these SNP markers and analyze 100 Burkholderia genomic DNAs extracted from environmental, clinical and near neighbor isolates from Australian collaborators on the Burkholderia SNP microarray. We will analyze the microarray genotyping results to characterize the genetic diversity of these new isolates and triage the samples for whole genome sequencing. In this interim report, we described the SNP analysis and the microarray probe design for the Burkholderia SNP microarray.

Gardner, S; Jaing, C

2012-03-27

197

Detection of Burkholderia pseudomallei in blood samples using polymerase chain reaction  

Microsoft Academic Search

A highly sensitive, specific, rapid and simple method to detectBurkholderia pseudomalleiin blood samples was developed. Two 22-base oligonucleotide primers, based on sequences from a specific DNA probe, were used for amplification of bacterial DNA by the polymerase chain reaction (PCR). Amplification with these primers yielded a 178-base pair product in 100 clinical isolates ofB. pseudomallei. As little as 0·5 fg

A. Rattanathongkom; R. W. Sermswan; S. Wongratanacheewin

1997-01-01

198

Identification and characterization of a two-component regulatory system involved in invasion of eukaryotic cells and heavy-metal resistance in Burkholderia pseudomallei.  

PubMed Central

Burkholderia pseudomallei is the causative agent of melioidosis, a disease increasingly recognized as an important cause of morbidity and mortality in many regions of the world. B. pseudomallei is a facultative intracellular pathogen capable of invading eukaryotic cells. We used Tn5-OT182 mutagenesis to generate mutants deficient in the ability to invade a human type II pneumocyte cell line (A549 cells). One of these mutants, AJ1D8, exhibited approximately 10% of the ability of the parental strain, 1026b, to invade A549 cells. There was no difference in the abilities of 1026b and AJ1D8 to resist killing by RAW macrophages or the human defensin HNP-1. The nucleotide sequence flanking the Tn5-OT182 integration in AJ1D8 was determined, and two open reading frames were identified. The predicted proteins shared considerable homology with two-component regulatory systems involved in the regulation of heavy-metal resistance in other organisms. AJ1D8 was 16-fold more sensitive to Cd2+ and twofold more sensitive to Zn2+ than was 1026b but was not sensitive to any of the other heavy metals examined. The B. pseudomallei two-component regulatory system, termed irlRS, complemented the invasion-deficient and heavy-metal-sensitive phenotype of AJ1D8 in trans. There was no significant difference between the virulence of AJ1D8 and that of 1026b in infant diabetic rats and Syrian hamsters, suggesting that the irlRS locus is probably not a virulence determinant in these animal models of acute B. pseudomallei infection. PMID:9393784

Jones, A L; DeShazer, D; Woods, D E

1997-01-01

199

Innate Immune Responses of Pulmonary Epithelial Cells to Burkholderia pseudomallei Infection  

PubMed Central

Background Burkholderia pseudomallei, a facultative intracellular pathogen, causes systemic infection in humans with high mortality especially when infection occurs through an infectious aerosol. Previous studies indicated that the epithelial cells in the lung are an active participant in host immunity. In this study, we aimed to investigate the innate immune responses of lung epithelial cells against B. pseudomallei. Methodology and Principal Findings Using a murine lung epithelial cell line, primary lung epithelial cells and an inhalational murine infection model, we characterized the types of innate immunity proteins and peptides produced upon B. pseudomallei infection. Among a wide panel of immune components studied, increased levels of major pro-inflammatory cytokines IL-6 and TNF?, chemokine MCP-1, and up-regulation of secretory leukocyte protease inhibitor (SLPI) and chemokine (C-C motif) ligand 20 (CCL20) were observed. Inhibition assays using specific inhibitors suggested that NF-?B and p38 MAPK pathways were responsible for these B. pseudomallei-induced antimicrobial peptides. Conclusions Our findings indicate that the respiratory epithelial cells, which form the majority of the cells lining the epithelial tract and the lung, have important roles in the innate immune response against B. pseudomallei infection. PMID:19806192

Sim, Siew Hoon; Liu, Yichun; Wang, Dongling; Novem, Vidhya; Sivalingam, Suppiah Paramalingam; Thong, Tuck Weng; Ooi, Eng Eong; Tan, Gladys

2009-01-01

200

The role of NOD2 in murine and human melioidosis  

PubMed Central

NOD2 is a cytosolic pathogen recognition receptor that regulates susceptibility to a variety of infections and chronic diseases. Burkholderia pseudomallei, a facultative intracellular bacterium, causes the tropical infection melioidosis. We hypothesized that NOD2 may participate in host defense in melioidosis. We performed a series of in vitro assays and in vivo experiments, and analyzed the association of human genetic variation with infection to delineate the contribution of NOD2 to the host response to B. pseudomallei. We found that transfection with NOD2 mediated NF-?B activation induced by B. pseudomallei stimulation of HEK293 cells. After low dose inoculation with aerosolized B. pseudomallei, Nod2-deficient mice showed impaired clinical responses and permitted greater bacterial replication in the lung and dissemination to the spleen compared to wild type mice. IL-6 and KC levels were higher in the lungs of Nod2-deficient mice. In a cohort of 1,562 Thai subjects, a common genetic polymorphism in the NOD2 region, rs7194886, was associated with melioidosis and this effect was most pronounced in women. rs7194886 was not associated with differences in cytokine production induced by whole blood stimulation with the NOD2 ligand, MDP, or B. pseudomallei. These findings are the first to characterize the role of NOD2 in host defense in mammalian melioidosis. PMID:24298015

Myers, Nicolle D.; Chantratita, Narisara; Berrington, William R.; Chierakul, Wirongrong; Limmathurotsakul, Direk; Wuthiekanun, Vanaporn; Robertson, Johanna D.; Liggitt, H. Denny; Peacock, Sharon J.; Skerrett, Shawn J.; West, T. Eoin

2013-01-01

201

Type three secretion system-mediated escape of Burkholderia pseudomallei into the host cytosol is critical for the activation of NF?B  

PubMed Central

Background Burkholderia pseudomallei is the causative agent of melioidosis, a potentially fatal disease endemic in Southeast Asia and Northern Australia. This Gram-negative pathogen possesses numerous virulence factors including three “injection type” type three secretion systems (T3SSs). B. pseudomallei has been shown to activate NF?B in HEK293T cells in a Toll-like receptor and MyD88 independent manner that requires T3SS gene cluster 3 (T3SS3 or T3SSBsa). However, the mechanism of how T3SS3 contributes to NF?B activation is unknown. Results Known T3SS3 effectors are not responsible for NF?B activation. Furthermore, T3SS3-null mutants are able to activate NF?B almost to the same extent as wildtype bacteria at late time points of infection, corresponding to delayed escape into the cytosol. NF?B activation also occurs when bacteria are delivered directly into the cytosol by photothermal nanoblade injection. Conclusions T3SS3 does not directly activate NF?B but facilitates bacterial escape into the cytosol where the host is able to sense the presence of the pathogen through cytosolic sensors leading to NF?B activation. PMID:24884837

2014-01-01

202

Melioidosis in a patient on monoclonal antibody therapy for psoriatic arthritis.  

PubMed

Melioidosis is caused by the environmental bacterium Burkholderia pseudomallei and can present with severe sepsis. Predisposing risk factors are present in 80% of cases. Monoclonal antibodies are increasingly prescribed for varied medical conditions. This report describes the first known case of melioidosis in a patient whose only risk factor for disease is treatment with a monoclonal antibody. Prescribers of monoclonal antibodies and other immunosuppressants should ensure that their patients are aware of the potential risk of melioidosis prior to travel and the precautions that should be taken. PMID:25442759

Commons, R J; Grivas, R; Currie, B J

2014-12-01

203

Nasal Acai Polysaccharides Potentiate Innate Immunity to Protect against Pulmonary Francisella tularensis and Burkholderia pseudomallei Infections  

PubMed Central

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 as an immunotherapeutic to treat F. tularensis and B. pseudomallei infections. In vitro, Acai PS impaired replication of Francisella in primary human macrophages co-cultured with autologous NK cells via augmentation of NK cell IFN-?. Furthermore, Acai PS administered nasally before or after infection protected mice against type A F. tularensis aerosol challenge with survival rates up to 80%, and protection was still observed, albeit reduced, when mice were treated two days post-infection. Nasal Acai PS administration augmented intracellular expression of IFN-? by NK cells in the lungs of F. tularensis-infected mice, and neutralization of IFN-? ablated the protective effect of Acai PS. Likewise, nasal Acai PS treatment conferred protection against pulmonary infection with B. pseudomallei strain 1026b. Acai PS dramatically reduced the replication of B. pseudomallei in the lung and blocked bacterial dissemination to the spleen and liver. Nasal administration of Acai PS enhanced IFN-? responses by NK and ?? T cells in the lungs, while neutralization of IFN-? totally abrogated the protective effect of Acai PS against pulmonary B. pseudomallei infection. Collectively, these results demonstrate Acai PS is a potent innate immune agonist that can resolve F. tularensis and B. pseudomallei infections, suggesting this innate immune agonist has broad-spectrum activity against virulent intracellular pathogens. PMID:22438809

Skyberg, Jerod A.; Rollins, MaryClare F.; Holderness, Jeff S.; Marlenee, Nicole L.; Schepetkin, Igor A.; Goodyear, Andrew; Dow, Steven W.; Jutila, Mark A.; Pascual, David W.

2012-01-01

204

Burkholderia pseudomallei activates complement and is ingested but not killed by polymorphonuclear leukocytes.  

PubMed

The mechanism by which Burkholderia pseudomallei is resistant to lysis by human serum is unknown but may include interference with complement activation, effective opsonization, or complement-mediated lysis. We investigated the interaction of B. pseudomallei with complement in the presence and absence of specific antibody to determine potential mechanisms of serum resistance. We demonstrated rapid activation and consumption of complement by B. pseudomallei which, in the absence of specific antibody, occurred predominantly via the alternative pathway. Complement activation was associated with deposition of the opsonically active C3b and iC3b fragments on the bacterial surface. C5b-9, detected on the bacterial surface after opsonic periods of 1 to 60 min, was susceptible to elution by 1 M NaCl, indicating that resistance to complement-mediated lysis may result from deposition of the membrane attack complex in a nonmicrobicidal location. To define the role of opsonins, we investigated the ability of polymorphonuclear leukocytes (PMNL) to phagocytose B. pseudomallei. Phagocytosis of bacteria by PMNL, and the observed oxidative response, was significantly increased by opsonization of organisms with complement and/or specific antibody. Despite opsonophagocytosis by PMNL and the production of an oxidative response, no significant bacterial killing was observed. PMID:8945532

Egan, A M; Gordon, D L

1996-12-01

205

Burkholderia pseudomallei activates complement and is ingested but not killed by polymorphonuclear leukocytes.  

PubMed Central

The mechanism by which Burkholderia pseudomallei is resistant to lysis by human serum is unknown but may include interference with complement activation, effective opsonization, or complement-mediated lysis. We investigated the interaction of B. pseudomallei with complement in the presence and absence of specific antibody to determine potential mechanisms of serum resistance. We demonstrated rapid activation and consumption of complement by B. pseudomallei which, in the absence of specific antibody, occurred predominantly via the alternative pathway. Complement activation was associated with deposition of the opsonically active C3b and iC3b fragments on the bacterial surface. C5b-9, detected on the bacterial surface after opsonic periods of 1 to 60 min, was susceptible to elution by 1 M NaCl, indicating that resistance to complement-mediated lysis may result from deposition of the membrane attack complex in a nonmicrobicidal location. To define the role of opsonins, we investigated the ability of polymorphonuclear leukocytes (PMNL) to phagocytose B. pseudomallei. Phagocytosis of bacteria by PMNL, and the observed oxidative response, was significantly increased by opsonization of organisms with complement and/or specific antibody. Despite opsonophagocytosis by PMNL and the production of an oxidative response, no significant bacterial killing was observed. PMID:8945532

Egan, A M; Gordon, D L

1996-01-01

206

Intracerebral coinfection with Burkholderia pseudomallei and Cryptococcus neoformans in a patient with systemic lupus erythematosus.  

PubMed

Infections are a serious complication in patients with systemic lupus erythematosus (SLE), and are an important cause of morbidity and mortality. SLE patients are particularly susceptible to infection due to immune suppression from underlying disease or treatment. Most infections are due to common bacterial organisms. Clinicians also need to be aware of the possibility of polymicrobial infections as these may cause diagnostic delay and affect outcomes. We report the case of an intra-cerebral coinfection with Burkholderia pseudomallei and Cryptococcus neoformans in a 34-year-old woman with SLE. The diagnosis in this case was delayed since coinfection was not suspected. PMID:24968675

Samad, Irenawati; Wang, Margaret Choon Lee; Chong, Vui Heng

2014-03-01

207

The aftermath of the Western Australian melioidosis outbreak.  

PubMed

Melioidosis became a notifiable disease in Western Australia (WA) 2 years after the West Kimberley melioidosis outbreak. Two cases of melioidosis caused by the outbreak genotype of Burkholderia pseudomallei (National Collection of Type Cultures [NCTC] 13177) occurred in 1998 and 1999 in persons who visited the outbreak location at the time. No other infections caused by the outbreak strain have been recorded in WA since that time, despite an average of four culture-positive cases per year. Sporadic cases of melioidosis often follow tropical storms and cyclones during summer, and they have been detected outside the endemic area when cyclones travel far inland. In 2007, environmental isolates resembling NCTC 13177 were found 500 km east of the outbreak location after unusually severe weather. Recent whole-genome analysis places NCTC 13177 genetically close to other Australian isolates. Additional biogeographic and ecological studies are needed to establish the relative importance of environmental cofactors in disease pathogenesis. PMID:21633018

Inglis, Timothy J J; O'Reilly, Lyn; Merritt, Adam J; Levy, Avram; Heath, Christopher H; Heath, Christopher

2011-06-01

208

Development of a Prototype Lateral Flow Immunoassay (LFI) for the Rapid Diagnosis of Melioidosis  

PubMed Central

Burkholderia pseudomallei is a soil-dwelling bacterium and the causative agent of melioidosis. Isolation of B. pseudomallei from clinical samples is the “gold standard” for the diagnosis of melioidosis; results can take 3–7 days to produce. Alternatively, antibody-based tests have low specificity due to a high percentage of seropositive individuals in endemic areas. There is a clear need to develop a rapid point-of-care antigen detection assay for the diagnosis of melioidosis. Previously, we employed In vivo Microbial Antigen Discovery (InMAD) to identify potential B. pseudomallei diagnostic biomarkers. The B. pseudomallei capsular polysaccharide (CPS) and numerous protein antigens were identified as potential candidates. Here, we describe the development of a diagnostic immunoassay based on the detection of CPS. Following production of a CPS-specific monoclonal antibody (mAb), an antigen-capture immunoassay was developed to determine the concentration of CPS within a panel of melioidosis patient serum and urine samples. The same mAb was used to produce a prototype Active Melioidosis Detect Lateral Flow Immunoassay (AMD LFI); the limit of detection of the LFI for CPS is comparable to the antigen-capture immunoassay (?0.2 ng/ml). The analytical reactivity (inclusivity) of the AMD LFI was 98.7% (76/77) when tested against a large panel of B. pseudomallei isolates. Analytical specificity (cross-reactivity) testing determined that 97.2% of B. pseudomallei near neighbor species (35/36) were not reactive. The non-reactive B. pseudomallei strain and the reactive near neighbor strain can be explained through genetic sequence analysis. Importantly, we show the AMD LFI is capable of detecting CPS in a variety of patient samples. The LFI is currently being evaluated in Thailand and Australia; the focus is to optimize and validate testing procedures on melioidosis patient samples prior to initiation of a large, multisite pre-clinical evaluation. PMID:24651568

Houghton, Raymond L.; Reed, Dana E.; Hubbard, Mark A.; Dillon, Michael J.; Chen, Hongjing; Currie, Bart J.; Mayo, Mark; Sarovich, Derek S.; Theobald, Vanessa; Limmathurotsakul, Direk; Wongsuvan, Gumphol; Chantratita, Narisara; Peacock, Sharon J.; Hoffmaster, Alex R.; Duval, Brea; Brett, Paul J.; Burtnick, Mary N.; AuCoin, David P.

2014-01-01

209

Production of a recombinant vaccine candidate against Burkholderia pseudomallei exploiting the bacterial N-glycosylation machinery  

PubMed Central

Vaccines developing immune responses toward surface carbohydrates conjugated to proteins are effective in preventing infection and death by bacterial pathogens. Traditional production of these vaccines utilizes complex synthetic chemistry to acquire and conjugate the glycan to a protein. However, glycoproteins produced by bacterial protein glycosylation systems are significantly easier to produce, and could possible be used as vaccine candidates. In this work, we functionally expressed the Burkholderia pseudomallei O polysaccharide (OPS II), the Campylobacter jejuni oligosaccharyltransferase (OTase), and a suitable glycoprotein (AcrA) in a designer E. coli strain with a higher efficiency for production of glycoconjugates. We were able to produce and purify the OPS II-AcrA glycoconjugate, and MS analysis confirmed correct glycan was produced and attached. We observed the attachment of the O-acetylated deoxyhexose directly to the acceptor protein, which expands the range of substrates utilized by the OTase PglB. Injection of the glycoprotein into mice generated an IgG immune response against B. pseudomallei, and this response was partially protective against an intranasal challenge. Our experiments show that bacterial engineered glycoconjugates can be utilized as vaccine candidates against B. pseudomallei. Additionally, our new E. coli strain SDB1 is more efficient in glycoprotein production, and could have additional applications in the future. PMID:25120536

Garcia-Quintanilla, Fatima; Iwashkiw, Jeremy A.; Price, Nancy L.; Stratilo, Chad; Feldman, Mario F.

2014-01-01

210

Identification of Burkholderia pseudomallei genes required for the intracellular life cycle and in vivo virulence.  

PubMed

The bacterial pathogen Burkholderia pseudomallei invades host cells, escapes from endocytic vesicles, multiplies intracellularly, and induces the formation of actin tails and membrane protrusions, leading to direct cell-to-cell spreading. This study was aimed at the identification of B. pseudomallei genes responsible for the different steps of this intracellular life cycle. B. pseudomallei transposon mutants were screened for a reduced ability to form plaques on PtK2 cell monolayers as a result of reduced intercellular spreading. Nine plaque assay mutants with insertions in different open reading frames were selected for further studies. One mutant defective in a hypothetical protein encoded within the Bsa type III secretion system gene cluster was found to be unable to escape from endocytic vesicles after invasion but still multiplied within the vacuoles. Another mutant with a defect in a putative exported protein reached the cytoplasm but exhibited impaired actin tail formation in addition to a severe intracellular growth defect. In four mutants, the transposon had inserted into genes involved in either purine, histidine, or p-aminobenzoate biosynthesis, suggesting that these pathways are essential for intracellular growth. Three mutants with reduced plaque formation were shown to have gene defects in a putative cytidyltransferase, a putative lipoate-protein ligase B, and a hypothetical protein. All nine mutants proved to be significantly attenuated in a murine model of infection, with some mutants being essentially avirulent. In conclusion, we have identified a number of novel major B. pseudomallei virulence genes which are essential for the intracellular life cycle of this pathogen. PMID:16714590

Pilatz, Sabine; Breitbach, Katrin; Hein, Nadine; Fehlhaber, Beate; Schulze, Jessika; Brenneke, Birgit; Eberl, Leo; Steinmetz, Ivo

2006-06-01

211

Delineating the importance of serum opsonins and the bacterial capsule in affecting the uptake and killing of Burkholderia pseudomallei by murine neutrophils and macrophages.  

PubMed

Infection of susceptible hosts by the encapsulated Gram-negative bacterium Burkholderia pseudomallei (Bp) causes melioidosis, with septic patients attaining mortality rates ? 40%. Due to its high infectivity through inhalation and limited effective therapies, Bp is considered a potential bioweapon. Thus, there is great interest in identifying immune effectors that effectively kill Bp. Our goal is to compare the relative abilities of murine macrophages and neutrophils to clear Bp, as well as determine the importance of serum opsonins and bacterial capsule. Our findings indicate that murine macrophages and neutrophils are inherently unable to clear either unopsonized Bp or the relatively-avirulent acapsular bacterium B. thailandensis (Bt). Opsonization of Bp and Bt with complement or pathogen-specific antibodies increases macrophage-uptake, but does not promote clearance, although antibody-binding enhances complement deposition. In contrast, complement opsonization of Bp and Bt causes enhanced uptake and killing by neutrophils, which is linked with rapid ROS induction against bacteria exhibiting a threshold level of complement deposition. Addition of bacteria-specific antibodies enhances complement deposition, but antibody-binding alone cannot elicit neutrophil clearance. Bp capsule provides some resistance to complement deposition, but is not anti-phagocytic or protective against reactive oxygen species (ROS)-killing. Macrophages were observed to efficiently clear Bp only after pre-activation with IFN?, which is independent of serum- and/or antibody-opsonization. These studies indicate that antibody-enhanced complement activation is sufficient for neutrophil-clearance of Bp, whereas macrophages are ineffective at clearing serum-opsonized Bp unless pre-activated with IFN?. This suggests that effective immune therapies would need to elicit both antibodies and Th1-adaptive responses for successful prevention/eradication of melioidosis. PMID:25144195

Mulye, Minal; Bechill, Michael P; Grose, William; Ferreira, Viviana P; Lafontaine, Eric R; Wooten, R Mark

2014-08-01

212

Delineating the Importance of Serum Opsonins and the Bacterial Capsule in Affecting the Uptake and Killing of Burkholderia pseudomallei by Murine Neutrophils and Macrophages  

PubMed Central

Infection of susceptible hosts by the encapsulated Gram-negative bacterium Burkholderia pseudomallei (Bp) causes melioidosis, with septic patients attaining mortality rates ?40%. Due to its high infectivity through inhalation and limited effective therapies, Bp is considered a potential bioweapon. Thus, there is great interest in identifying immune effectors that effectively kill Bp. Our goal is to compare the relative abilities of murine macrophages and neutrophils to clear Bp, as well as determine the importance of serum opsonins and bacterial capsule. Our findings indicate that murine macrophages and neutrophils are inherently unable to clear either unopsonized Bp or the relatively-avirulent acapsular bacterium B. thailandensis (Bt). Opsonization of Bp and Bt with complement or pathogen-specific antibodies increases macrophage-uptake, but does not promote clearance, although antibody-binding enhances complement deposition. In contrast, complement opsonization of Bp and Bt causes enhanced uptake and killing by neutrophils, which is linked with rapid ROS induction against bacteria exhibiting a threshold level of complement deposition. Addition of bacteria-specific antibodies enhances complement deposition, but antibody-binding alone cannot elicit neutrophil clearance. Bp capsule provides some resistance to complement deposition, but is not anti-phagocytic or protective against reactive oxygen species (ROS)-killing. Macrophages were observed to efficiently clear Bp only after pre-activation with IFN?, which is independent of serum- and/or antibody-opsonization. These studies indicate that antibody-enhanced complement activation is sufficient for neutrophil-clearance of Bp, whereas macrophages are ineffective at clearing serum-opsonized Bp unless pre-activated with IFN?. This suggests that effective immune therapies would need to elicit both antibodies and Th1-adaptive responses for successful prevention/eradication of melioidosis. PMID:25144195

Mulye, Minal; Bechill, Michael P.; Grose, William; Ferreira, Viviana P.; Lafontaine, Eric R.; Wooten, R. Mark

2014-01-01

213

Population-Sequencing as a Biomarker of Burkholderia mallei and Burkholderia pseudomallei Evolution through Microbial Forensic Analysis  

PubMed Central

Large-scale genomics projects are identifying biomarkers to detect human disease. B. pseudomallei and B. mallei are two closely related select agents that cause melioidosis and glanders. Accurate characterization of metagenomic samples is dependent on accurate measurements of genetic variation between isolates with resolution down to strain level. Often single biomarker sensitivity is augmented by use of multiple or panels of biomarkers. In parallel with single biomarker validation, advances in DNA sequencing enable analysis of entire genomes in a single run: population-sequencing. Potentially, direct sequencing could be used to analyze an entire genome to serve as the biomarker for genome identification. However, genome variation and population diversity complicate use of direct sequencing, as well as differences caused by sample preparation protocols including sequencing artifacts and mistakes. As part of a Department of Homeland Security program in bacterial forensics, we examined how to implement whole genome sequencing (WGS) analysis as a judicially defensible forensic method for attributing microbial sample relatedness; and also to determine the strengths and limitations of whole genome sequence analysis in a forensics context. Herein, we demonstrate use of sequencing to provide genetic characterization of populations: direct sequencing of populations. PMID:24455204

Jakupciak, John P.; Wells, Jeffrey M.; Karalus, Richard J.; Pawlowski, David R.; Lin, Jeffrey S.; Feldman, Andrew B.

2013-01-01

214

Burkholderia mallei and Burkholderia pseudomallei Cluster 1 Type VI Secretion System Gene Expression Is Negatively Regulated by Iron and Zinc  

PubMed Central

Burkholderia mallei is a facultative intracellular pathogen that causes glanders in humans and animals. Previous studies have demonstrated that the cluster 1 type VI secretion system (T6SS-1) expressed by this organism is essential for virulence in hamsters and is positively regulated by the VirAG two-component system. Recently, we have shown that T6SS-1 gene expression is up-regulated following internalization of this pathogen into phagocytic cells and that this system promotes multinucleated giant cell formation in infected tissue culture monolayers. In the present study, we further investigated the complex regulation of this important virulence factor. To assess T6SS-1 expression, B. mallei strains were cultured in various media conditions and Hcp1 production was analyzed by Western immunoblotting. Transcript levels of several VirAG-regulated genes (bimA, tssA, hcp1 and tssM) were also determined using quantitative real time PCR. Consistent with previous observations, T6SS-1 was not expressed during growth of B. mallei in rich media. Curiously, growth of the organism in minimal media (M9G) or minimal media plus casamino acids (M9CG) facilitated robust expression of T6SS-1 genes whereas growth in minimal media plus tryptone (M9TG) did not. Investigation of this phenomenon confirmed a regulatory role for VirAG in this process. Additionally, T6SS-1 gene expression was significantly down-regulated by the addition of iron and zinc to M9CG. Other genes under the control of VirAG did not appear to be as tightly regulated by these divalent metals. Similar results were observed for B. pseudomallei, but not for B. thailandensis. Collectively, our findings indicate that in addition to being positively regulated by VirAG, B. mallei and B. pseudomallei T6SS-1 gene expression is negatively regulated by iron and zinc. PMID:24146925

Burtnick, Mary N.; Brett, Paul J.

2013-01-01

215

Clinical features of diabetes mellitus cases complicated by Burkholderia pseudomallei septicemia.  

PubMed

The aim of this study was to analyze the clinical characteristics of diabetes mellitus patients with Burkholderia pseudomallei septicemia and evaluate strategies of diagnosis and treatment. The clinical characteristics, diagnosis, treatment, and prognosis of 39 diabetes mellitus patients with B. pseudomallei septicemia were retrospectively analyzed. Farmers, fishermen and workers were found to be high-risk groups. The clinical manifestations of patients were diverse without specific features, but mainly presented manifestations of acute fulminant septicemia, diabetic ketoacidosis, and abscesses in tissues or/and organs. Patients showed high mortality and misdiagnosis rates and were prone to relapses and long treatment duration as there are currently few effective and sensitive antibiotics for the disease. Consequently, the cost of treatment for the disease was high. Early diagnosis, a prolonged course of heavy doses of sensitive intravenous antibiotics, drainage of abscesses, intensive insulin therapy, and supportive treatment are the keys for successful management of the disease. Regular follow-ups combined with long-term blood glucose control can help reduce the disease recurrence. PMID:24782168

Quan, H B; Li, T Y; Gao, Y Y; Chen, D X

2014-01-01

216

The HicA toxin from Burkholderia pseudomallei has a role in persister cell formation.  

PubMed

TA (toxin-antitoxin) systems are widely distributed amongst bacteria and are associated with the formation of antibiotic tolerant (persister) cells that may have involvement in chronic and recurrent disease. We show that overexpression of the Burkholderia pseudomallei HicA toxin causes growth arrest and increases the number of persister cells tolerant to ciprofloxacin or ceftazidime. Furthermore, our data show that persistence towards ciprofloxacin or ceftazidime can be differentially modulated depending on the level of induction of HicA expression. Deleting the hicAB locus from B. pseudomallei K96243 significantly reduced persister cell frequencies following exposure to ciprofloxacin, but not ceftazidime. The structure of HicA(H24A) was solved by NMR and forms a dsRBD-like (dsRNA-binding domain-like) fold, composed of a triple-stranded ?-sheet, with two helices packed against one face. The surface of the protein is highly positively charged indicative of an RNA-binding protein and His24 and Gly22 were functionality important residues. This is the first study demonstrating a role for the HicAB system in bacterial persistence and the first structure of a HicA protein that has been experimentally characterized. PMID:24502667

Butt, Aaron; Higman, Victoria A; Williams, Christopher; Crump, Matthew P; Hemsley, Claudia M; Harmer, Nicholas; Titball, Richard W

2014-04-15

217

The HicA toxin from Burkholderia pseudomallei has a role in persister cell formation  

PubMed Central

TA (toxin–antitoxin) systems are widely distributed amongst bacteria and are associated with the formation of antibiotic tolerant (persister) cells that may have involvement in chronic and recurrent disease. We show that overexpression of the Burkholderia pseudomallei HicA toxin causes growth arrest and increases the number of persister cells tolerant to ciprofloxacin or ceftazidime. Furthermore, our data show that persistence towards ciprofloxacin or ceftazidime can be differentially modulated depending on the level of induction of HicA expression. Deleting the hicAB locus from B. pseudomallei K96243 significantly reduced persister cell frequencies following exposure to ciprofloxacin, but not ceftazidime. The structure of HicA(H24A) was solved by NMR and forms a dsRBD-like (dsRNA-binding domain-like) fold, composed of a triple-stranded ?-sheet, with two helices packed against one face. The surface of the protein is highly positively charged indicative of an RNA-binding protein and His24 and Gly22 were functionality important residues. This is the first study demonstrating a role for the HicAB system in bacterial persistence and the first structure of a HicA protein that has been experimentally characterized. PMID:24502667

Butt, Aaron; Higman, Victoria A.; Williams, Christopher; Crump, Matthew P.; Hemsley, Claudia M.; Harmer, Nicholas; Titball, Richard W.

2014-01-01

218

High-Throughput mRNA Profiling Characterizes the Expression of Inflammatory Molecules in Sepsis Caused by Burkholderia pseudomallei  

Microsoft Academic Search

Sepsis is characterized by an uncontrolled inflammatory response to invading microorganisms. We describe the inflammatory mRNA profiles in whole-blood leukocytes, monocytes, and granulocytes using a multigene system for 35 inflammatory markers that included pro- and anti-inflammatory cytokines, chemokines, and signal transduction molecules in a case-control study with 34 patients with sepsis caused by the gram-negative bacterium Burkholderia pseudomallei (the pathogen

W. Joost Wiersinga; Mark C. Dessing; Piet A. Kager; Allen C. Cheng; Direk Limmathurotsakul; Nicholas P. Day; Arjen M. Dondorp; Tom van der Poll; Sharon J. Peacock

2007-01-01

219

[Melioidosis in a Danish tourist returning from North-eastern Thailand.  

PubMed

Melioidosis, an infectious disease caused by Burkholderia pseudomallei, is endemic in South East Asia and Northern Australia. It has a wide clinical diversity, spanning from asymptomatic cases to rapid septic shock and death. We present a case of pulmonary melioidosis in a Danish tourist returning from North-eastern Thailand. The patient was treated with intravenous ceftazidime followed by oral therapy with trimethoprim/sulfamethoxazole and subsequently switched to doxycycline due to abnormal liver function tests and eosinophilia, with no sign of relapse two months after antibiotic cessation. PMID:25096943

Leth, Steffen; Wang, Mikala; Deutch, Susanna

2014-06-01

220

The coagulation system in melioidosis: from pathogenesis to new treatment strategies.  

PubMed

Melioidosis, caused by the Gram-negative bacterium Burkholderia pseudomallei, is a dreadful disease common in South-East Asia and Northern Australia and is characterized by chronic suppurative lesions and pneumonia. Melioidosis may evolve into severe sepsis with multi-organ failure with high mortalities, despite proper antibiotic therapy. Besides activation of a strong pro-inflammatory host response, the coagulation system plays an important role during melioidosis, which is thought to be host-protective. In particular, a procoagulant state together with downregulation of anticoagulant pathways and activation of fibrinolysis are present, all closely interrelated with parameters of inflammation. This review presents an overview of recent studies in which the role of coagulation, anti-coagulation and fibrinolysis during melioidosis was investigated both in patients and in experimental settings. PMID:24962103

Kager, Liesbeth Martine; van der Poll, Tom; Wiersinga, Willem Joost

2014-08-01

221

Acute melioidosis outbreak in Western Australia.  

PubMed Central

A cluster of acute melioidosis cases occurred in a remote, coastal community in tropical Western Australia. Molecular typing of Burkholderia pseudomallei isolates from culture-confirmed cases and suspected environmental sources by pulsed-field gel electrophoresis (PFGE) of XbaI chromosomal DNA digests showed that a single PFGE type was responsible for five cases of acute infection in a community of around 300 during a 5 week period. This temporal and geographical clustering of acute melioidosis cases provided a unique opportunity to investigate the environmental factors contributing to this disease. B. pseudomallei isolated from a domestic tap at the home of an asymptomatic seroconverter was indistinguishable by PFGE. Possible contributing environmental factors included an unusually acid communal water supply, unrecordable chlorine levels during the probable exposure period, a nearby earth tremor, and gusting winds during the installation of new water and electricity supplies. The possible role of the potable water supply as a source of B. pseudomallei was investigated further. PMID:10694154

Inglis, T. J.; Garrow, S. C.; Adams, C.; Henderson, M.; Mayo, M.; Currie, B. J.

1999-01-01

222

NLRC4 and TLR5 each contribute to host defense in respiratory melioidosis.  

PubMed

Burkholderia pseudomallei causes the tropical infection melioidosis. Pneumonia is a common manifestation of melioidosis and is associated with high mortality. Understanding the key elements of host defense is essential to developing new therapeutics for melioidosis. As a flagellated bacterium encoding type III secretion systems, B. pseudomallei may trigger numerous host pathogen recognition receptors. TLR5 is a flagellin sensor located on the plasma membrane. NLRC4, along with NAIP proteins, assembles a canonical caspase-1-dependent inflammasome in the cytoplasm that responds to flagellin (in mice) and type III secretion system components (in mice and humans). In a murine model of respiratory melioidosis, Tlr5 and Nlrc4 each contributed to survival. Mice deficient in both Tlr5 and Nlrc4 were not more susceptible than single knockout animals. Deficiency of Casp1/Casp11 resulted in impaired bacterial control in the lung and spleen; in the lung much of this effect was attributable to Nlrc4, despite relative preservation of pulmonary IL-1? production in Nlrc4(-/-) mice. Histologically, deficiency of Casp1/Casp11 imparted more severe pulmonary inflammation than deficiency of Nlrc4. The human NLRC4 region polymorphism rs6757121 was associated with survival in melioidosis patients with pulmonary involvement. Co-inheritance of rs6757121 and a functional TLR5 polymorphism had an additive effect on survival. Our results show that NLRC4 and TLR5, key components of two flagellin sensing pathways, each contribute to host defense in respiratory melioidosis. PMID:25232720

West, T Eoin; Myers, Nicolle D; Chantratita, Narisara; Chierakul, Wirongrong; Limmathurotsakul, Direk; Wuthiekanun, Vanaporn; Miao, Edward A; Hajjar, Adeline M; Peacock, Sharon J; Liggitt, H Denny; Skerrett, Shawn J

2014-09-01

223

Melioidosis: Epidemiology, Pathophysiology, and Management  

PubMed Central

Melioidosis, caused by the gram-negative saprophyte Burkholderia pseudomallei, is a disease of public health importance in southeast Asia and northern Australia that is associated with high case-fatality rates in animals and humans. It has the potential for epidemic spread to areas where it is not endemic, and sporadic case reports elsewhere in the world suggest that as-yet-unrecognized foci of infection may exist. Environmental determinants of this infection, apart from a close association with rainfall, are yet to be elucidated. The sequencing of the genome of a strain of B. pseudomallei has recently been completed and will help in the further identification of virulence factors. The presence of specific risk factors for infection, such as diabetes, suggests that functional neutrophil defects are important in the pathogenesis of melioidosis; other studies have defined virulence factors (including a type III secretion system) that allow evasion of killing mechanisms by phagocytes. There is a possible role for cell-mediated immunity, but repeated environmental exposure does not elicit protective humoral or cellular immunity. A vaccine is under development, but economic constraints may make vaccination an unrealistic option for many regions of endemicity. Disease manifestations are protean, and no inexpensive, practical, and accurate rapid diagnostic tests are commercially available; diagnosis relies on culture of the organism. Despite the introduction of ceftazidime- and carbapenem-based intravenous treatments, melioidosis is still associated with a significant mortality attributable to severe sepsis and its complications. A long course of oral eradication therapy is required to prevent relapse. Studies exploring the role of preventative measures, earlier clinical identification, and better management of severe sepsis are required to reduce the burden of this disease. PMID:15831829

Cheng, Allen C.; Currie, Bart J.

2005-01-01

224

Source-Identifying Biomarker Ions between Environmental and Clinical Burkholderia pseudomallei Using Whole-Cell Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS)  

PubMed Central

Burkholderia pseudomallei is the causative agent of melioidosis, which is an endemic disease in Northeast Thailand and Northern Australia. Environmental reservoirs, including wet soils and muddy water, serve as the major sources for contributing bacterial infection to both humans and animals. The whole-cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (whole-cell MALDI-TOF MS) has recently been applied as a rapid, accurate, and high-throughput tool for clinical diagnosis and microbiological research. In this present study, we employed a whole-cell MALDI-TOF MS approach for assessing its potency in clustering a total of 11 different B. pseudomallei isolates (consisting of 5 environmental and 6 clinical isolates) with respect to their origins and to further investigate the source-identifying biomarker ions belonging to each bacterial group. The cluster analysis demonstrated that six out of eleven isolates were grouped correctly to their sources. Our results revealed a total of ten source-identifying biomarker ions, which exhibited statistically significant differences in peak intensity between average environmental and clinical mass spectra using ClinProTools software. Six out of ten mass ions were assigned as environmental-identifying biomarker ions (EIBIs), including, m/z 4,056, 4,214, 5,814, 7,545, 7,895, and 8,112, whereas the remaining four mass ions were defined as clinical-identifying biomarker ions (CIBIs) consisting of m/z 3,658, 6,322, 7,035, and 7,984. Hence, our findings represented, for the first time, the source-specific biomarkers of environmental and clinical B. pseudomallei. PMID:24914956

Srisanga, Kitima; Roytrakul, Sittiruk; Tungpradabkul, Sumalee

2014-01-01

225

Burkholderia vaccines: are we moving forward?  

PubMed Central

The genus Burkholderia consists of diverse species which includes both “friends” and “foes.” Some of the “friendly” Burkholderia spp. are extensively used in the biotechnological and agricultural industry for bioremediation and biocontrol. However, several members of the genus including B. pseudomallei, B. mallei, and B. cepacia, are known to cause fatal disease in both humans and animals. B. pseudomallei and B. mallei are the causative agents of melioidosis and glanders, respectively, while B. cepacia infection is lethal to cystic fibrosis (CF) patients. Due to the high rate of infectivity and intrinsic resistance to many commonly used antibiotics, together with high mortality rate, B. mallei and B. pseudomallei are considered to be potential biological warfare agents. Treatments of the infections caused by these bacteria are often unsuccessful with frequent relapse of the infection. Thus, we are at a crucial stage of the need for Burkholderia vaccines. Although the search for a prophylactic therapy candidate continues, to date development of vaccines has not advanced beyond research to human clinical trials. In this article, we review the current research on development of safe vaccines with high efficacy against B. pseudomallei, B. mallei, and B. cepacia. It can be concluded that further research will enable elucidation of the potential benefits and risks of Burkholderia vaccines. PMID:23386999

Choh, Leang-Chung; Ong, Guang-Han; Vellasamy, Kumutha M.; Kalaiselvam, Kaveena; Kang, Wen-Tyng; Al-Maleki, Anis R.; Mariappan, Vanitha; Vadivelu, Jamuna

2013-01-01

226

Burkholderia vaccines: are we moving forward?  

PubMed

The genus Burkholderia consists of diverse species which includes both "friends" and "foes." Some of the "friendly" Burkholderia spp. are extensively used in the biotechnological and agricultural industry for bioremediation and biocontrol. However, several members of the genus including B. pseudomallei, B. mallei, and B. cepacia, are known to cause fatal disease in both humans and animals. B. pseudomallei and B. mallei are the causative agents of melioidosis and glanders, respectively, while B. cepacia infection is lethal to cystic fibrosis (CF) patients. Due to the high rate of infectivity and intrinsic resistance to many commonly used antibiotics, together with high mortality rate, B. mallei and B. pseudomallei are considered to be potential biological warfare agents. Treatments of the infections caused by these bacteria are often unsuccessful with frequent relapse of the infection. Thus, we are at a crucial stage of the need for Burkholderia vaccines. Although the search for a prophylactic therapy candidate continues, to date development of vaccines has not advanced beyond research to human clinical trials. In this article, we review the current research on development of safe vaccines with high efficacy against B. pseudomallei, B. mallei, and B. cepacia. It can be concluded that further research will enable elucidation of the potential benefits and risks of Burkholderia vaccines. PMID:23386999

Choh, Leang-Chung; Ong, Guang-Han; Vellasamy, Kumutha M; Kalaiselvam, Kaveena; Kang, Wen-Tyng; Al-Maleki, Anis R; Mariappan, Vanitha; Vadivelu, Jamuna

2013-01-01

227

Intramolecular aglycon delivery enables the synthesis of 6-deoxy-?-D-manno-heptosides as fragments of Burkholderia pseudomallei and Burkholderia mallei capsular polysaccharide.  

PubMed

Burkholderia pseudomallei and Burkholderia mallei are potential bioterrorism agents. They express the same capsular polysaccharide (CPS), a homopolymer featuring an unusual [?3)-2-O-acetyl-6-deoxy-?-D-manno-heptopyranosyl-(1?] as the repeating unit. This CPS is known to be one of the main targets of the adaptive immune response in humans and therefore represents a crucial subunit candidate for vaccine development. Herein, the stereoselective synthesis of mono- and disaccharidic fragments of the B. pseudomallei and B. mallei CPS repeating unit is reported. The synthesis of 6-deoxy-?-D-manno-heptosides was investigated using both inter- and intramolecular glycosylation strategies from thio-manno-heptose that was modified with 2-naphthylmethyl (NAP) at C2. We show here that NAP-mediated intramolecular aglycon delivery (IAD) represents a suitable approach for the stereocontrolled synthesis of 6-deoxy-?-D-manno-heptosides without the need for rigid 4,6-O-cyclic protection of the sugar skeleton. The IAD strategy is highly modular, as it can be applied to structurally diverse acceptors with complete control of stereoselectivity. Problematic hydrogenation of the acetylated disaccharides was overcome by using a microfluidic continuous flow reactor. PMID:24786555

Tamigney Kenfack, Marielle; Blériot, Yves; Gauthier, Charles

2014-05-16

228

Whole-Genome Sequencing Confirms that Burkholderia pseudomallei Multilocus Sequence Types Common to Both Cambodia and Australia Are Due to Homoplasy.  

PubMed

Burkholderia pseudomallei isolates with shared multilocus sequence types (STs) have not been isolated from different continents. We identified two STs shared between Australia and Cambodia. Whole-genome analysis revealed substantial diversity within STs, correctly identified the Asian or Australian origin, and confirmed that these shared STs were due to homoplasy. PMID:25392354

De Smet, Birgit; Sarovich, Derek S; Price, Erin P; Mayo, Mark; Theobald, Vanessa; Kham, Chun; Heng, Seiha; Thong, Phe; Holden, Matthew T G; Parkhill, Julian; Peacock, Sharon J; Spratt, Brian G; Jacobs, Jan A; Vandamme, Peter; Currie, Bart J

2015-01-01

229

rpsU-based discrimination within the genus Burkholderia.  

PubMed

Sequencing of the gene rpsU reliably delineates saprophytic Burkholderia (B.) thailandensis from highly pathogenic B. mallei and B. pseudomallei. We analyzed the suitability of this technique for the delineation of the B. pseudomallei complex from other Burkholderia species. Both newly recorded and previously deposited sequences of well-characterized or reference strains (n = 84) of Azoarcus spp., B. ambifaria, B. anthina, B. caledonica, B. caribensis, B. caryophylli, B. cenocepacia, B. cepacia, B. cocovenenans, B. dolosa, B. fungorum, B. gladioli, B. glathei, B. glumae, B. graminis, B. hospita, B. kururensis, B. mallei, B. multivorans, B. phenazinium, B. phenoliruptrix, B. phymatum, B. phytofirmans, B. plantarii, B. pseudomallei, B. pyrrocinia, B. stabilis, B. thailandensis, B. ubonensis, B. vietnamiensis, B. xenovorans, not further defined Burkholderia spp., and the outliers Cupriavidus metallidurans, Laribacter hongkongensis, Pandorea norimbergensis, and Ralstonia pickettii were included in a multiple sequence analysis. Multiple sequence alignments led to the delineation of four major clusters, rpsU-I to rpsU-IV, with a sequence homology >92%. The B. pseudomallei complex formed the complex rpsU-II. Several Burkholderia species showed 100% sequence homology. This procedure is useful for the molecular confirmation or exclusion of glanders or melioidosis from primary patient material. Further discrimination within the Burkholderia genus requires other molecular approaches. PMID:24883196

Frickmann, H; Neubauer, H; Loderstaedt, U; Derschum, H; Hagen, R M

2014-06-01

230

Construction and characterization of stable, constitutively expressed, chromosomal green and red fluorescent transcriptional fusions in the select agents, Bacillus anthracis, Yersinia pestis, Burkholderia mallei, and Burkholderia pseudomallei.  

PubMed

Here, we constructed stable, chromosomal, constitutively expressed, green and red fluorescent protein (GFP and RFP) as reporters in the select agents, Bacillus anthracis, Yersinia pestis, Burkholderia mallei, and Burkholderia pseudomallei. Using bioinformatic approaches and other experimental analyses, we identified P0253 and P1 as potent promoters that drive the optimal expression of fluorescent reporters in single copy in B. anthracis and Burkholderia spp. as well as their surrogate strains, respectively. In comparison, Y. pestis and its surrogate strain need two chromosomal copies of cysZK promoter (P2cysZK) for optimal fluorescence. The P0253-, P2cysZK-, and P1-driven GFP and RFP fusions were first cloned into the vectors pRP1028, pUC18R6KT-mini-Tn7T-Km, pmini-Tn7-gat, or their derivatives. The resultant constructs were delivered into the respective surrogates and subsequently into the select agent strains. The chromosomal GFP- and RFP-tagged strains exhibited bright fluorescence at an exposure time of less than 200 msec and displayed the same virulence traits as their wild-type parental strains. The utility of the tagged strains was proven by the macrophage infection assays and lactate dehydrogenase release analysis. Such strains will be extremely useful in high-throughput screens for novel compounds that could either kill these organisms, or interfere with critical virulence processes in these important bioweapon agents and during infection of alveolar macrophages. PMID:25044501

Su, Shengchang; Bangar, Hansraj; Saldanha, Roland; Pemberton, Adin; Aronow, Bruce; Dean, Gary E; Lamkin, Thomas J; Hassett, Daniel J

2014-10-01

231

Comparison of Automated and Nonautomated Systems for Identification of Burkholderia pseudomallei  

Microsoft Academic Search

identification of uncommonly encountered organisms such as B. pseudomallei critically important. This study compares the manual API 20NE and 20E identification systems with the automated Vitek 1 and 2 systems. A total of 103 B. pseudomallei isolates were tested and correctly identified in 98%, 99%, 99%, and 19% of cases, respectively. The failure of the Vitek 2 to correctly identify

Peter Lowe; Catherine Engler; Robert Norton

2002-01-01

232

Treatment and prophylaxis of melioidosis.  

PubMed

Melioidosis, infection with Burkholderia pseudomallei, is being recognised with increasing frequency and is probably more common than currently appreciated. Treatment recommendations are based on a series of clinical trials conducted in Thailand over the past 25 years. Treatment is usually divided into two phases: in the first, or acute phase, parenteral drugs are given for ?10 days with the aim of preventing death from overwhelming sepsis; in the second, or eradication phase, oral drugs are given, usually to complete a total of 20 weeks, with the aim of preventing relapse. Specific treatment for individual patients needs to be tailored according to clinical manifestations and response, and there remain many unanswered questions. Some patients with very mild infections can probably be cured by oral agents alone. Ceftazidime is the mainstay of acute-phase treatment, with carbapenems reserved for severe infections or treatment failures and amoxicillin/clavulanic acid (co-amoxiclav) as second-line therapy. Trimethoprim/sulfamethoxazole (co-trimoxazole) is preferred for the eradication phase, with the alternative of co-amoxiclav. In addition, the best available supportive care is needed, along with drainage of abscesses whenever possible. Treatment for melioidosis is unaffordable for many in endemic areas of the developing world, but the relative costs have reduced over the past decade. Unfortunately there is no likelihood of any new or cheaper options becoming available in the immediate future. Recommendations for prophylaxis following exposure to B. pseudomallei have been made, but the evidence suggests that they would probably only delay rather than prevent the development of infection. PMID:24613038

Dance, David

2014-04-01

233

Immunospecific Responses to Bacterial Elongation Factor Tu during Burkholderia Infection and Immunization  

Microsoft Academic Search

Burkholderia pseudomallei is the etiological agent of melioidosis, a disease endemic in parts of Southeast Asia and Northern Australia. Currently there is no licensed vaccine against infection with this biological threat agent. In this study, we employed an immunoproteomic approach and identified bacterial Elongation factor-Tu (EF-Tu) as a potential vaccine antigen. EF-Tu is membrane-associated, secreted in outer membrane vesicles (OMVs),

Wildaliz Nieves; Julie Heang; Saja Asakrah; Kerstin Höner zu Bentrup; Chad J. Roy; Lisa A. Morici

2010-01-01

234

Interaction of Interferon gamma-induced reactive oxygen species with ceftazidime leads to synergistic killing of intracellular Burkholderia pseudomallei.  

PubMed

Burkholderia pseudomallei, a facultative intracellular pathogen, causes severe infections and is inherently refractory to many antibiotics. Previous studies from our group have shown that interferon gamma (IFN-?) interacts synergistically with the antibiotic ceftazidime to kill bacteria in infected macrophages. The present study aimed to identify the underlying mechanism of that interaction. We first showed that blocking reactive oxygen species (ROS) pathways reversed IFN-?- and ceftazidime-mediated killing, which led to our hypothesis that IFN-?-induced ROS interacted with ceftazidime to synergistically kill Burkholderia bacteria. Consistent with this hypothesis, we also observed that buthionine sulfoximine (BSO), another inducer of ROS, could substitute for IFN-? to similarly potentiate the effect of ceftazidime on intracellular killing. Next, we observed that IFN-? induced ROS-mediated killing of intracellular but not extracellular bacteria. On the other hand, ceftazidime effectively reduced extracellular bacteria but was not capable of intracellular killing when applied at 10 ?g/ml. We investigated the exact role of IFN-?-induced ROS responses on intracellular bacteria and notably observed a lack of actin polymerization associated with Burkholderia bacteria in IFN-?-treated macrophages, which led to our finding that IFN-?-induced ROS blocks vacuolar escape. Based on these results, we propose a model in which synergistically reduced bacterial burden is achieved primarily through separate and compartmentalized killing: intracellular killing by IFN-?-induced ROS responses and extracellular killing by ceftazidime. Our findings suggest a means of enhancing antibiotic activity against Burkholderia bacteria through combination with drugs that induce ROS pathways or otherwise target intracellular spread and/or replication of bacteria. PMID:25070108

Mosovsky, Kara; Silva, Ediane; Troyer, Ryan; Propst-Graham, Katie; Dow, Steven

2014-10-01

235

Effect of gamma irradiation on Burkholderia thailandensis ( Burkholderia pseudomallei surrogate) survival under combinations of pH and NaCl  

NASA Astrophysics Data System (ADS)

This study evaluated the effect of gamma irradiation on Burkholderia thailandensis ( Burkholderia pseudomallei surrogate; potential bioterrorism agent) survival under different levels of NaCl and pH. B. thailandensis in Luria Bertani broth supplemented with NaCl (0-3%), and pH-adjusted to 4-7 was treated with gamma irradiation (0-0.5 kGy). Surviving cell counts of bacteria were then enumerated on tryptic soy agar. Data for the cell counts were also used to calculate D10 values (the dose required to reduce 1 log CFU/mL of B. thailandensis). Cell counts of B. thailandensis were decreased ( P<0.05) as irradiation dose increased, and no differences ( P?0.05) in cell counts of the bacteria were observed among different levels of NaCl and pH. D10 values ranged from 0.04 to 0.07 kGy, regardless of NaCl and pH level. These results indicate that low doses of gamma irradiation should be a useful treatment in decreasing the potential bioterrorism bacteria, which may possibly infect humans through foods.

Yoon, Yohan; Kim, Jae-Hun; Byun, Myung-Woo; Choi, Kyoung-Hee; Lee, Ju-Woon

2010-04-01

236

The role of short-chain dehydrogenase/oxidoreductase, induced by salt stress, on host interaction of B. pseudomallei  

PubMed Central

Background Burkholderia pseudomallei is the causative agent of melioidosis, a frequently occurring disease in northeastern Thailand, where soil and water high in salt content are common. Using microarray analysis, we previously showed that B. pseudomallei up-regulated a short-chain dehydrogenase/oxidoreductase (SDO) under salt stress. However, the importance of SDO in B. pseudomallei infection is unknown. This study aimed to explore the function of B. pseudomallei SDO, and to investigate its role in interactions between B. pseudomallei and host cells. Results Bioinformatics analysis of B. pseudomallei SDO structure, based on homology modeling, revealed a NAD+ cofactor domain and a catalytic triad containing Ser149, Tyr162, and Lys166. This is similar to Bacillus megaterium glucose 1-dehydrogenase. To investigate the role of this protein, we constructed a B. pseudomallei SDO defective mutant, measured glucose dehydrogenase (GDH) activity, and tested the interactions with host cells. The B. pseudomallei K96243 wild type exhibited potent GDH activity under condition containing 300 mM NaCl, while the mutant showed activity levels 15 times lower. Both invasion into the A549 cell line and early intracellular survival within the J774A.1 macrophage cell were impaired in the mutant. Complementation of SDO was able to restore the mutant ability to produce GDH activity, invade epithelial cells, and survive in macrophages. Conclusions Our data suggest that induced SDO activity during salt stress may facilitate B. pseudomallei invasion and affect initiation of successful intracellular infection. Identifying the role of B. pseudomallei SDO provides a better understanding of the association between bacterial adaptation and pathogenesis in melioidosis. PMID:24382268

2014-01-01

237

In Vitro Activities of Amoxicillin-Clavulanate, Doxycycline, Ceftazidime, Imipenem, and Trimethoprim-Sulfamethoxazole against Biofilm of Brazilian Strains of Burkholderia pseudomallei  

PubMed Central

This study aimed at investigating the in vitro activities of amoxicillin-clavulanate, doxycycline, ceftazidime, imipenem, and trimethoprim-sulfamethoxazole against Burkholderia pseudomallei in planktonic and biofilm forms, through broth microdilution and resazurin-based viability staining, respectively. In planktonic growth, the strains were susceptible to the drugs, while in biofilm growth, significantly higher antimicrobial concentrations were required, especially for ceftazidime and imipenem, surpassing the resistance breakpoints. These results highlight the importance of the routine evaluation of biofilm antimicrobial susceptibility. PMID:24002089

Bandeira, Tereza de Jesus Pinheiro Gomes; Moreira, Camila Alencar; Castelo-Branco, Débora de Souza Collares Maia; Neto, Manoel Paiva de Araújo; Cordeiro, Rossana de Aguiar; Rodrigues, Terezinha de Jesus Santos; Rocha, Marcos Fábio Gadelha; Sidrim, José Júlio Costa

2013-01-01

238

Type 3 secretion system cluster 3 is a critical virulence determinant for lung-specific melioidosis.  

PubMed

Burkholderia pseudomallei, the bacterial agent of melioidosis, causes disease through inhalation of infectious particles, and is classified as a Tier 1 Select Agent. Optical diagnostic imaging has demonstrated that murine respiratory disease models are subject to significant upper respiratory tract (URT) colonization. Because human melioidosis is not associated with URT colonization as a prominent presentation, we hypothesized that lung-specific delivery of B. pseudomallei may enhance our ability to study respiratory melioidosis in mice. We compared intranasal and intubation-mediated intratracheal (IMIT) instillation of bacteria and found that the absence of URT colonization correlates with an increased bacterial pneumonia and systemic disease progression. Comparison of the LD50 of luminescent B. pseudomallei strain, JW280, in intranasal and IMIT challenges of albino C57BL/6J mice identified a significant decrease in the LD50 using IMIT. We subsequently examined the LD50 of both capsular polysaccharide and Type 3 Secretion System cluster 3 (T3SS3) mutants by IMIT challenge of mice and found that the capsule mutant was attenuated 6.8 fold, while the T3SS3 mutant was attenuated 290 fold, demonstrating that T3SS3 is critical to respiratory melioidosis. Our previously reported intranasal challenge studies, which involve significant URT colonization, did not identify a dissemination defect for capsule mutants; however, we now report that capsule mutants exhibit significantly reduced dissemination from the lung following lung-specific instillation, suggesting that capsule mutants are competent to spread from the URT, but not the lung. We also report that a T3SS3 mutant is defective for dissemination following lung-specific delivery, and also exhibits in vivo growth defects in the lung. These findings highlight the T3SS3 as a critical virulence system for respiratory melioidosis, not only in the lung, but also for subsequent spread beyond the lung using a model system uniquely capable to characterize the fate of lung-delivered pathogen. PMID:25569630

Gutierrez, Maria G; Pfeffer, Tia L; Warawa, Jonathan M

2015-01-01

239

Type 3 Secretion System Cluster 3 Is a Critical Virulence Determinant for Lung-Specific Melioidosis  

PubMed Central

Burkholderia pseudomallei, the bacterial agent of melioidosis, causes disease through inhalation of infectious particles, and is classified as a Tier 1 Select Agent. Optical diagnostic imaging has demonstrated that murine respiratory disease models are subject to significant upper respiratory tract (URT) colonization. Because human melioidosis is not associated with URT colonization as a prominent presentation, we hypothesized that lung-specific delivery of B. pseudomallei may enhance our ability to study respiratory melioidosis in mice. We compared intranasal and intubation-mediated intratracheal (IMIT) instillation of bacteria and found that the absence of URT colonization correlates with an increased bacterial pneumonia and systemic disease progression. Comparison of the LD50 of luminescent B. pseudomallei strain, JW280, in intranasal and IMIT challenges of albino C57BL/6J mice identified a significant decrease in the LD50 using IMIT. We subsequently examined the LD50 of both capsular polysaccharide and Type 3 Secretion System cluster 3 (T3SS3) mutants by IMIT challenge of mice and found that the capsule mutant was attenuated 6.8 fold, while the T3SS3 mutant was attenuated 290 fold, demonstrating that T3SS3 is critical to respiratory melioidosis. Our previously reported intranasal challenge studies, which involve significant URT colonization, did not identify a dissemination defect for capsule mutants; however, we now report that capsule mutants exhibit significantly reduced dissemination from the lung following lung-specific instillation, suggesting that capsule mutants are competent to spread from the URT, but not the lung. We also report that a T3SS3 mutant is defective for dissemination following lung-specific delivery, and also exhibits in vivo growth defects in the lung. These findings highlight the T3SS3 as a critical virulence system for respiratory melioidosis, not only in the lung, but also for subsequent spread beyond the lung using a model system uniquely capable to characterize the fate of lung-delivered pathogen. PMID:25569630

Gutierrez, Maria G.; Pfeffer, Tia L.; Warawa, Jonathan M.

2015-01-01

240

Comparative experimental subcutaneous glanders and melioidosis in the common marmoset (Callithrix jacchus).  

PubMed

Glanders and melioidosis are caused by two distinct Burkholderia species and have generally been considered to have similar disease progression. While both of these pathogens are HHS/CDC Tier 1 agents, natural infection with both these pathogens is primarily through skin inoculation. The common marmoset (Callithrix jacchus) was used to compare disease following experimental subcutaneous challenge. Acute, lethal disease was observed in marmosets following challenge with between 26 and 1.2 × 10(8)  cfu Burkholderia pseudomallei within 22-85 h. The reproducibility and progression of the disease were assessed following a challenge of 1 × 10(2)  cfu of B. pseudomallei. Melioidosis was characterised by high levels of bacteraemia, focal microgranuloma progressing to non-necrotic multifocal solid lesions in the livers and spleens and multi-organ failure. Lethal disease was observed in 93% of animals challenged with Burkholderia mallei, occurring between 5 and 10.6 days. Following challenge with 1 × 10(2)  cfu of B. mallei, glanders was characterised with lymphatic spread of the bacteria and non-necrotic, multifocal solid lesions progressing to a multifocal lesion with severe necrosis and pneumonia. The experimental results confirmed that the disease pathology and presentation is strikingly different between the two pathogens. The marmoset provides a model of the human syndrome for both diseases facilitating the development of medical countermeasures. PMID:25477002

Nelson, Michelle; Salguero, Francisco J; Dean, Rachel E; Ngugi, Sarah A; Smither, Sophie J; Atkins, Timothy P; Lever, Mark S

2014-12-01

241

Clinically lesser known entity in India: A Report of two cases of Melioidosis  

PubMed Central

Melioidosis is endemic in the South Asian regions, like Thailand, Singapore Malaysia and Australia. The disease is more pronounced in the southern part of the country. It is caused by Burkholderia pseudomallei which causes systemic involvement, morbidity and mortality associated with the disease is high. Due to highly varied clinical presentation, and low general awareness this infection is largely underdiagnosed and under reported in our country. Most laboratories in the country still rely on conventional culturing methods with their low sensitivity, adding to the under reporting. To enhance physician awareness we describe here two cases who presented to our institute after months of misdiagnosis. PMID:23833477

Barman, Purabi; Kaur, Ravneet; Kumar, Kamlesh

2013-01-01

242

Nitric oxide from IFN?-primed macrophages modulates the antimicrobial activity of ?-lactams against the intracellular pathogens Burkholderia pseudomallei and Nontyphoidal Salmonella.  

PubMed

Our investigations show that nonlethal concentrations of nitric oxide (NO) abrogate the antibiotic activity of ?-lactam antibiotics against Burkholderia pseudomallei, Escherichia coli and nontyphoidal Salmonella enterica serovar Typhimurium. NO protects B. pseudomallei already exposed to ?-lactams, suggesting that this diatomic radical tolerizes bacteria against the antimicrobial activity of this important class of antibiotics. The concentrations of NO that elicit antibiotic tolerance repress consumption of oxygen (O2), while stimulating hydrogen peroxide (H2O2) synthesis. Transposon insertions in genes encoding cytochrome c oxidase-related functions and molybdenum assimilation confer B. pseudomallei a selective advantage against the antimicrobial activity of the ?-lactam antibiotic imipenem. Cumulatively, these data support a model by which NO induces antibiotic tolerance through the inhibition of the electron transport chain, rather than by potentiating antioxidant defenses as previously proposed. Accordingly, pharmacological inhibition of terminal oxidases and nitrate reductases tolerizes aerobic and anaerobic bacteria to ?-lactams. The degree of NO-induced ?-lactam antibiotic tolerance seems to be inversely proportional to the proton motive force (PMF), and thus the dissipation of ?H+ and ?? electrochemical gradients of the PMF prevents ?-lactam-mediated killing. According to this model, NO generated by IFN?-primed macrophages protects intracellular Salmonella against imipenem. On the other hand, sublethal concentrations of imipenem potentiate the killing of B. pseudomallei by NO generated enzymatically from IFN?-primed macrophages. Our investigations indicate that NO modulates the antimicrobial activity of ?-lactam antibiotics. PMID:25121731

Jones-Carson, Jessica; Zweifel, Adrienne E; Tapscott, Timothy; Austin, Chad; Brown, Joseph M; Jones, Kenneth L; Voskuil, Martin I; Vázquez-Torres, Andrés

2014-08-01

243

Nitric Oxide from IFN?-Primed Macrophages Modulates the Antimicrobial Activity of ?-Lactams against the Intracellular Pathogens Burkholderia pseudomallei and Nontyphoidal Salmonella  

PubMed Central

Our investigations show that nonlethal concentrations of nitric oxide (NO) abrogate the antibiotic activity of ?-lactam antibiotics against Burkholderia pseudomallei, Escherichia coli and nontyphoidal Salmonella enterica serovar Typhimurium. NO protects B. pseudomallei already exposed to ?-lactams, suggesting that this diatomic radical tolerizes bacteria against the antimicrobial activity of this important class of antibiotics. The concentrations of NO that elicit antibiotic tolerance repress consumption of oxygen (O2), while stimulating hydrogen peroxide (H2O2) synthesis. Transposon insertions in genes encoding cytochrome c oxidase-related functions and molybdenum assimilation confer B. pseudomallei a selective advantage against the antimicrobial activity of the ?-lactam antibiotic imipenem. Cumulatively, these data support a model by which NO induces antibiotic tolerance through the inhibition of the electron transport chain, rather than by potentiating antioxidant defenses as previously proposed. Accordingly, pharmacological inhibition of terminal oxidases and nitrate reductases tolerizes aerobic and anaerobic bacteria to ?-lactams. The degree of NO-induced ?-lactam antibiotic tolerance seems to be inversely proportional to the proton motive force (PMF), and thus the dissipation of ?H+ and ?? electrochemical gradients of the PMF prevents ?-lactam-mediated killing. According to this model, NO generated by IFN?-primed macrophages protects intracellular Salmonella against imipenem. On the other hand, sublethal concentrations of imipenem potentiate the killing of B. pseudomallei by NO generated enzymatically from IFN?-primed macrophages. Our investigations indicate that NO modulates the antimicrobial activity of ?-lactam antibiotics. PMID:25121731

Jones-Carson, Jessica; Zweifel, Adrienne E.; Tapscott, Timothy; Austin, Chad; Brown, Joseph M.; Jones, Kenneth L.; Voskuil, Martin I.; Vázquez-Torres, Andrés

2014-01-01

244

Redefining the PF06864 Pfam Family Based on Burkholderia pseudomallei PilO2Bp S-SAD Crystal Structure  

PubMed Central

Type IV pili are surface-exposed filaments and bacterial virulence factors, represented by the Tfpa and Tfpb types, which assemble via specific machineries. The Tfpb group is further divided into seven variants, linked to heterogeneity in the assembly machineries. Here we focus on PilO2Bp, a protein component of the Tfpb R64 thin pilus variant assembly machinery from the pathogen Burkholderia pseudomallei. PilO2Bp belongs to the PF06864 Pfam family, for which an improved definition is presented based on newly derived Hidden Markov Model (HMM) profiles. The 3D structure of the N-terminal domain of PilO2Bp (N-PilO2Bp), here reported, is the first structural representative of the PF06864 family. N-PilO2Bp presents an actin-like ATPase fold that is shown to be present in BfpC, a different variant assembly protein; the new HMM profiles classify BfpC as a PF06864 member. Our results provide structural insight into the PF06864 family and on the Type IV pili assembly machinery. PMID:24728008

Manjasetty, Babu A.; Yero, Daniel; Perletti, Lucia; Belrhali, Hassan; Daura, Xavier; Gourlay, Louise J.; Bolognesi, Martino

2014-01-01

245

Structural characterization of the Ser324Thr variant of the catalase-peroxidase (KatG) from Burkholderia pseudomallei.  

PubMed

The Ser315Thr variant of the catalase-peroxidase KatG from Mycobacterium tuberculosis imparts resistance to the pro-drug isonicotinic acid hydrazide (isoniazid) through a failure to convert it to the active drug, isonicotinoyl-NAD. The equivalent variant in KatG from Burkholderia pseudomallei, Ser324Thr, has been constructed, revealing catalase and peroxidase activities that are similar to those of the native enzyme. The other activities of the variant protein, including the NADH oxidase, the isoniazid hydrazinolysis and isonicotinoyl-NAD synthase activities are reduced by 60-70%. The crystal structure of the variant differs from that of the native enzyme in having the methyl group of Thr324 situated in the entrance channel to the heme cavity, in a modified water matrix in the entrance channel and heme cavity, in lacking the putative perhydroxy modification on the heme, in the multiple locations of a few side-chains, and in the presence of an apparent perhydroxy modification on the indole nitrogen atom of the active-site Trp111. The position of the methyl group of Thr324 creates a constriction or narrowing of the channel leading to the heme cavity, providing an explanation for the lower reactivity towards isoniazid and the slower rate of isonicotinoyl-NAD synthesis. PMID:15567407

Deemagarn, Taweewat; Carpena, Xavier; Singh, Rahul; Wiseman, Ben; Fita, Ignacio; Loewen, Peter C

2005-01-01

246

Efficient inactivation of Burkholderia pseudomallei or Francisella tularensis in infected cells for safe removal from biosafety level 3 containment laboratories.  

PubMed

Working with infectious agents that require BSL-3 level containment agents offers many challenges for researchers. BSL-3 containment laboratories are usually not equipped with expensive specialty equipment that is needed for studies such as flow cytometric analysis, microscopy, and proteomic analyses. Therefore, for most researchers that are working with BSL-3 level infectious agents, removal of samples from BSL-3 laboratories for these types of studies is necessary, and methods for complete and dependable inactivation of the samples are required. In this report, we have carried out a thorough characterization of the effectiveness of paraformaldehyde fixation for inactivation of cell samples infected with the intracellular bacterial agents Burkholderia pseudomallei (Bp) and Francisella tularensis (Ft), both of which are Tier 1 select agent pathogens that require BSL-3 containment. We have demonstrated that cells infected with these pathogens are completely inactivated via 5-min treatment with 4% paraformaldehyde. Moreover, a 15-min treatment with 2% paraformaldehyde completely sterilized both Bp- and Ft-infected cells. These studies also revealed that Bp is significantly more sensitive to paraformaldehyde treatment than Ft. Our findings have clearly demonstrated that a 15-min treatment of Bp- or Ft-infected cells with 4% paraformaldehyde solution will allow for safe removal of the cell samples from BSL-3 laboratories for downstream studies. PMID:24449562

Emery, Felicia D; Stabenow, Jennifer M; Miller, Mark A

2014-07-01

247

Protection against Experimental Melioidosis following Immunisation with a Lipopolysaccharide-Protein Conjugate  

PubMed Central

Melioidosis is a severe infectious disease caused by Burkholderia pseudomallei. It is refractory to antibiotic treatment and there is currently no licensed vaccine. In this report we detail the construction and protective efficacy of a polysaccharide-protein conjugate composed of B. pseudomallei lipopolysaccharide and the Hc fragment of tetanus toxin. Immunisation of mice with the lipopolysaccharide-conjugate led to significantly reduced bacterial burdens in the spleen 48 hours after challenge and afforded significant protection against a lethal challenge with B. pseudomallei. The conjugate generated significantly higher levels of antigen-specific IgG1 and IgG2a than in lipopolysaccharide-immunised mice. Immunisation with the conjugate also demonstrated a bias towards Th1 type responses, evidenced by high levels of IgG2a. In contrast, immunisation with unconjugated lipopolysaccharide evoked almost no IgG2a demonstrating a bias towards Th2 type responses. This study demonstrates the effectiveness of this approach in the development of an efficacious and protective vaccine against melioidosis. PMID:24892035

Scott, Andrew E.; Ngugi, Sarah A.; Laws, Thomas R.; Corser, David; Lonsdale, Claire L.; D'Elia, Riccardo V.; Titball, Richard W.; Williamson, E. Diane; Atkins, Timothy P.; Prior, Joann L.

2014-01-01

248

A non-invasive intratracheal inoculation method for the study of pulmonary melioidosis  

PubMed Central

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 describe a method which requires relatively inexpensive equipment, little training, and is compliant with the operational constraints of a BSL3 laboratory. Results obtained using trypan blue demonstrated that an inoculum can be accurately delivered into the lungs of mice within a biosafety cabinet (BSC). Whole body imaging and histopathology confirmed that mice inoculated intratracheally with B. pseudomallei develop the primary focus of infection in the lungs, and not the nasal passages which can lead to invasion of the central nervous system and potential neurologic complications. Further, based on colony counts and bioluminescent imaging, dissemination to secondary organs occurred as expected. Taken together, this intratracheal method of inoculation fulfills four goals: (1) to accurately deliver B. pseudomallei into the lungs of the animal model, (2) to avoid potentially confounding complications due to primary infections at sites other than the lung, (3) to maintain normal organ dissemination, and (4) to be BSL3 compliant. PMID:23267442

Revelli, David A.; Boylan, Julie A.; Gherardini, Frank C.

2012-01-01

249

BurkDiff: A Real-Time PCR Allelic Discrimination Assay for Burkholderia Pseudomallei and B. mallei  

PubMed Central

A real-time PCR assay, BurkDiff, was designed to target a unique conserved region in the B. pseudomallei and B. mallei genomes containing a SNP that differentiates the two species. Sensitivity and specificity were assessed by screening BurkDiff across 469 isolates of B. pseudomallei, 49 isolates of B. mallei, and 390 isolates of clinically relevant non-target species. Concordance of results with traditional speciation methods and no cross-reactivity to non-target species show BurkDiff is a robust, highly validated assay for the detection and differentiation of B. pseudomallei and B. mallei. PMID:21103048

Bowers, Jolene R.; Engelthaler, David M.; Ginther, Jennifer L.; Pearson, Talima; Peacock, Sharon J.; Tuanyok, Apichai; Wagner, David M.; Currie, Bart J.; Keim, Paul S.

2010-01-01

250

Cervical abscesses due to co-infection with Burkholderia pseudomallei, Salmonella enterica serovar Stanley and Mycobacterium tuberculosis in a patient with diabetes mellitus  

PubMed Central

Background Infections due to Mycobacterium tuberculosis, Burkholderia pseudomallei and non-typhoidal Salmonella cause significant morbidity and mortality throughout the world. These intracellular pathogens share some common predisposing factors and clinical features. Co-infection with two of these organisms has been reported previously but, to our knowledge, this is the first time that infection with all three has been reported in one person. Case presentation In September 2010, a 58-year-old diabetic Malaysian male presented with fever and a fluctuant mass on the right side of his neck. B. pseudomallei was isolated from an aspirate of this lesion and there was radiological evidence of disseminated infection in the liver and spleen. The recurrence of clinical symptoms over ensuing months prompted further aspiration and biopsy of a cervical abscess and underlying lymph nodes. Salmonella enterica serovar Stanley and then M. tuberculosis were identified from these specimens by culture and molecular methods. The patient responded to targeted medical management of each of these infections. Conclusion In endemic settings, a high index of suspicion and adequate tissue sampling are imperative in identifying these pathogenic organisms. Diabetes was identified as a predisposing factor in this case while our understanding of other potential risk factors is evolving. PMID:24209898

2013-01-01

251

Intensity of Rainfall and Severity of Melioidosis, Australia  

PubMed Central

In a 12-year prospective study of 318 culture-confirmed cases of melioidosis from the Top End of the Northern Territory of Australia, rainfall data for individual patient locations were correlated with patient risk factors, clinical parameters, and outcomes. Median rainfall in the 14 days before admission was highest for those dying with melioidosis (211 mm), in comparison to 110 mm for those surviving (p = 0.0002). Median 14-day rainfall was also significantly higher for those admitted with pneumonia. On univariate analysis, a prior 14-day rainfall of ?125 mm was significantly correlated with pneumonia (odds ratio [OR] 1.70 [confidence interval [CI] 1.09 to 2.65]), bacteremia (OR 1.93 [CI 1.24 to 3.02]), septic shock (OR 1.94 [CI 1.14 to 3.29]), and death (OR 2.50 [CI 1.36 to 4.57]). On multivariate analysis, rainfall in the 14 days before admission was an independent risk factor for pneumonia (p = 0.023), bacteremic pneumonia (p = 0.001), septic shock (p = 0.005), and death (p < 0.0001). Heavy monsoonal rains and winds may cause a shift towards inhalation of Burkholderia pseudomallei. PMID:14720392

Jacups, Susan P.

2003-01-01

252

In Vitro Susceptibilities of Burkholderia mallei in Comparison to Those of Other Pathogenic Burkholderia spp  

Microsoft Academic Search

The in vitro antimicrobial susceptibilities of isolates of Burkholderia mallei to 16 antibiotics were assessed and compared with the susceptibilities of Burkholderia pseudomallei and Burkholderia cepacia. The antibiotic susceptibility profile of B. mallei resembled that of B. pseudomallei more closely than that of B. cepacia, which corresponds to their similarities in terms of biochemistry, antigenicity, and pathogenicity. Ceftazidime, imi- penem,

D. J. KENNY; P. RUSSELL; D. ROGERS; S. M. ELEY; R. W. TITBALL

1999-01-01

253

Diabetes-independent increase of factor VII-activating protease activation in patients with Gram-negative sepsis (melioidosis)  

PubMed Central

Background The plasma protease factor VII-activating protease (FSAP) can release nucleosomes from late apoptotic cells. Nucleosomes are markers of cell death, and extracellular cell-free DNA has been suggested to play an important role in inflammation and has been demonstrated to correlate with severity and outcome in sepsis patients. Objective To investigate FSAP activation in patients suffering from Burkholderia pseudomallei infection (melioidosis), an important cause of Gram-negative sepsis in Southeast Asia. As diabetes mellitus (DM) is the most important risk factor for both melioidosis and sepsis, we were also able to examine the role of DM in FSAP activation in this cohort of patients. Methods In a prospective observational study, complexes of FSAP with ?2-antiplasmin (AP) were assayed in 44 patients with melioidosis, 34 of whom were classified as diabetic. Eighty-two healthy subjects served as controls (52 with DM and 30 without). Results FSAP–AP complex levels were markedly elevated in patients as compared with controls. The FSAP level increased by 16.82 AU mL?1 in patients with melioidosis after adjustment for the effect of DM in the regression model. As expected, FSAP activation was correlated with nucleosome release (slope = 0.74). No difference in FSAP activation on admission was seen between survivors and non-survivors, but the extent of FSAP activation correlated with stage of the disease; repeated testing during convalescence showed a return towards normal values (day 0 vs. day 28, 4.16 AU mL?1, 95% confidence interval [CI] 1.42–12.22). Conclusion Patients with Gram-negative sepsis caused by B. pseudomallei have abundant FSAP activation, which significantly correlates with stage of disease. The presence of DM, however, does not influence the extent of FSAP activation. PMID:25370187

de Jong, H K; Koh, G C K W; Bulder, I; Stephan, F; Wiersinga, W J; Zeerleder, S S

2015-01-01

254

Melioidosis and safety in the clinical laboratory.  

PubMed

Human infection with Pseudomonas pseudomallei, the causative agent of melioidosis, typically produces subclinical disease and an asymptomatic carrier state; occasionally clinical illness, frequently with a fatal outcome, may occur. Consequently, to help protect staff from laboratory-acquired melioidosis, microbiological and biomedical laboratories must have adequate facilities for safe work procedures and laboratory staff must engage in safe work practices. Recommendations from a melioidosis-endemic, diagnostic laboratory for the prevention of laboratory-acquired infection with this bacterium are essentially Category 3 (Advisory Committee on Dangerous Pathogens), Risk Group 3 (Australian Standards) or Biosafety Level 2 (National Institutes of Health) precautions. These include safeguards for centrifugation, prohibiting the 'sniff' test and the use of a biological safety cabinet for sputum processing, for subculture of stock strains, for preparation of antigen and for research studies but not for routine diagnostic techniques with P. pseudomallei. PMID:1355785

Ashdown, L R

1992-08-01

255

Neutrophil elastase causes tissue damage that decreases host tolerance to lung infection with burkholderia species.  

PubMed

Two distinct defense strategies can protect the host from infection: resistance is the ability to destroy the infectious agent, and tolerance is the ability to withstand infection by minimizing the negative impact it has on the host's health without directly affecting pathogen burden. Burkholderia pseudomallei is a Gram-negative bacterium that infects macrophages and causes melioidosis. We have recently shown that inflammasome-triggered pyroptosis and IL-18 are equally important for resistance to B. pseudomallei, whereas IL-1? is deleterious. Here we show that the detrimental role of IL-1? during infection with B. pseudomallei (and closely related B. thailandensis) is due to excessive recruitment of neutrophils to the lung and consequent tissue damage. Mice deficient in the potentially damaging enzyme neutrophil elastase were less susceptible than the wild type C57BL/6J mice to infection, although the bacterial burdens in organs and the extent of inflammation were comparable between C57BL/6J and elastase-deficient mice. In contrast, lung tissue damage and vascular leakage were drastically reduced in elastase-deficient mice compared to controls. Bradykinin levels were higher in C57BL/6 than in elastase-deficient mice; administration of a bradykinin antagonist protected mice from infection, suggesting that increased vascular permeability mediated by bradykinin is one of the mechanisms through which elastase decreases host tolerance to melioidosis. Collectively, these results demonstrate that absence of neutrophil elastase increases host tolerance, rather than resistance, to infection by minimizing host tissue damage. PMID:25166912

Sahoo, Manoranjan; Del Barrio, Laura; Miller, Mark A; Re, Fabio

2014-08-01

256

Neutrophil Elastase Causes Tissue Damage That Decreases Host Tolerance to Lung Infection with Burkholderia Species  

PubMed Central

Two distinct defense strategies can protect the host from infection: resistance is the ability to destroy the infectious agent, and tolerance is the ability to withstand infection by minimizing the negative impact it has on the host's health without directly affecting pathogen burden. Burkholderia pseudomallei is a Gram-negative bacterium that infects macrophages and causes melioidosis. We have recently shown that inflammasome-triggered pyroptosis and IL-18 are equally important for resistance to B. pseudomallei, whereas IL-1? is deleterious. Here we show that the detrimental role of IL-1? during infection with B. pseudomallei (and closely related B. thailandensis) is due to excessive recruitment of neutrophils to the lung and consequent tissue damage. Mice deficient in the potentially damaging enzyme neutrophil elastase were less susceptible than the wild type C57BL/6J mice to infection, although the bacterial burdens in organs and the extent of inflammation were comparable between C57BL/6J and elastase-deficient mice. In contrast, lung tissue damage and vascular leakage were drastically reduced in elastase-deficient mice compared to controls. Bradykinin levels were higher in C57BL/6 than in elastase-deficient mice; administration of a bradykinin antagonist protected mice from infection, suggesting that increased vascular permeability mediated by bradykinin is one of the mechanisms through which elastase decreases host tolerance to melioidosis. Collectively, these results demonstrate that absence of neutrophil elastase increases host tolerance, rather than resistance, to infection by minimizing host tissue damage. PMID:25166912

Miller, Mark A.; Re, Fabio

2014-01-01

257

The Burkholderia pseudomallei Enoyl-Acyl Carrier Protein Reductase FabI1 Is Essential for In Vivo Growth and Is the Target of a Novel Chemotherapeutic with Efficacy  

PubMed Central

The bacterial fatty acid biosynthesis pathway is a validated target for the development of novel chemotherapeutics. However, since Burkholderia pseudomallei carries genes that encode both FabI and FabV enoyl-acyl carrier protein (ACP) reductase homologues, the enoyl-ACP reductase that is essential for in vivo growth needs to be defined so that the correct drug target can be chosen for development. Accordingly, ?fabI1, ?fabI2, and ?fabV knockout strains were constructed and tested in a mouse model of infection. Mice infected with a ?fabI1 strain did not show signs of morbidity, mortality, or dissemination after 30 days of infection compared to the wild-type and ?fabI2 and ?fabV mutant strains that had times to mortality of 60 to 84 h. Although signs of morbidity and mortality of ?fabI2 and ?fabV strains were not significantly different from those of the wild-type strain, a slight delay was observed. A FabI1-specific inhibitor was used to confirm that inhibition of FabI1 results in reduced bacterial burden and efficacy in an acute B. pseudomallei murine model of infection. This work establishes that FabI1 is required for growth of Burkholderia pseudomallei in vivo and is a potential molecular target for drug development. PMID:24277048

Cummings, Jason E.; Kingry, Luke C.; Rholl, Drew A.; Schweizer, Herbert P.

2014-01-01

258

The Burkholderia pseudomallei enoyl-acyl carrier protein reductase FabI1 is essential for in vivo growth and is the target of a novel chemotherapeutic with efficacy.  

PubMed

The bacterial fatty acid biosynthesis pathway is a validated target for the development of novel chemotherapeutics. However, since Burkholderia pseudomallei carries genes that encode both FabI and FabV enoyl-acyl carrier protein (ACP) reductase homologues, the enoyl-ACP reductase that is essential for in vivo growth needs to be defined so that the correct drug target can be chosen for development. Accordingly, ?fabI1, ?fabI2, and ?fabV knockout strains were constructed and tested in a mouse model of infection. Mice infected with a ?fabI1 strain did not show signs of morbidity, mortality, or dissemination after 30 days of infection compared to the wild-type and ?fabI2 and ?fabV mutant strains that had times to mortality of 60 to 84 h. Although signs of morbidity and mortality of ?fabI2 and ?fabV strains were not significantly different from those of the wild-type strain, a slight delay was observed. A FabI1-specific inhibitor was used to confirm that inhibition of FabI1 results in reduced bacterial burden and efficacy in an acute B. pseudomallei murine model of infection. This work establishes that FabI1 is required for growth of Burkholderia pseudomallei in vivo and is a potential molecular target for drug development. PMID:24277048

Cummings, Jason E; Kingry, Luke C; Rholl, Drew A; Schweizer, Herbert P; Tonge, Peter J; Slayden, Richard A

2014-01-01

259

Characterization of a novel two-component system response regulator involved in biofilm formation and a low-iron response of Burkholderia pseudomallei.  

PubMed

Two-component systems (TCSs) regulate an adaptive response to environmental conditions, leading to changes in bacterial cellular processes. In this study, we identified a novel TCS response regulator gene, designated as bfmR (biofilm formation-associated regulator) that regulates biofilm formation by Burkholderia pseudomallei (Bp). An insertion mutant of the Bp bfmR gene resulted in a significant decrease in expression of fimbriae chaperone-usher assembly genes (BPSL2O28 and BPSL22 7), leading to suppression of assembly of fimbriae on the cell surface and reduced biofilm formation. The defective phenotypes of the mutant strain were restored by introducing a complementing plasmid having an intact bfmR gene. Using RT-PCR analyses, we found that bfmR gene expression was upregulated under low-iron growth conditions. In addition, the bfmR mutant strain showed retarded growth in low-iron medium and in phagocytic cells compared to the wild-type strain. These results indicate that bfmR is a novel positive regulator for controlling assembly of fimbriae and biofilm formation, and is upregulated under low-iron conditions. PMID:25507236

Tabunhan, Sompong; Wongratanacheewin, Surasakdi; Wongwajana, Suwin; Welbat, Tariva Umka; Faksri, Kiatichai; Namwat, Wises

2014-09-01

260

Characterization of a novel two-component system response regulator involved in biofilm formation and a low-iron response of Burkholderia pseudomallei.  

PubMed

Two-component systems (TCSs) regulate an adaptive response to environmental conditions, leading to changes in bacterial cellular processes. In this study, we identified a novel TCS response regulator gene, designated as bfmR (biofilm formation-associated regulator) that regulates biofilm formation by Burkholderia pseudomallei (Bp). An insertion mutant of the Bp bfmR gene resulted in a significant decrease in expression of fimbriae chaperone-usher assembly genes (BPSL2O28 and BPSL22 7), leading to suppression of assembly of fimbriae on the cell surface and reduced biofilm formation. The defective phenotypes of the mutant strain were restored by introducing a complementing plasmid having an intact bfmR gene. Using RT-PCR analyses, we found that bfmR gene expression was upregulated under low-iron growth conditions. In addition, the bfmR mutant strain showed retarded growth in low-iron medium and in phagocytic cells compared to the wild-type strain. These results indicate that bfmR is a novel positive regulator for controlling assembly of fimbriae and biofilm formation, and is upregulated under low-iron conditions. PMID:25417508

Tabunhan, Sompong; Wongratanacheewin, Surasakdi; Wongwajana, Suwin; Welbat, Tariva Umka; Faksri, Kiatichai; Namwat, Wises

2014-09-01

261

Development and Application of a Cellular, Gain-of-Signal, Bioluminescent Reporter Screen for Inhibitors of Type II Secretion in Pseudomonas aeruginosa and Burkholderia pseudomallei  

PubMed Central

The type II secretion (T2S) system in Gram-negative bacteria is comprised of 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, we used a Pseudomonas aeruginosa bioluminescent reporter strain responsive to SecA depletion and inhibition to screen compound libraries and characterize the hits. The reporter strain placed a luxCDABE operon under regulation of a SecA depletion-responsive up-regulated promoter in a secA deletion background complemented with an ectopic lac-regulated secA copy. Bioluminescence was indirectly proportional to the IPTG concentration and stimulated by azide, a known SecA ATPase inhibitor. A total of 96 compounds (0.1% of 73,000) were detected as primary hits due to stimulation of luminescence with a z-score ?5. Direct secretion assays of the 9 most potent hits, representing 5 chemical scaffolds, revealed that they do not inhibit SecA-mediated secretion of ?-lactamase into the periplasm, but do inhibit T2S-mediated extracellular secretion of elastase with IC50 values from 5 – 25 ?M. In addition, 7 of the 9 compounds also inhibited the T2S-mediated extracellular secretion of phospholipases C by P. aeruginosa and of protease activity by Burkholderia pseudomallei. PMID:21602485

Moir, Donald T.; Di, Ming; Wong, Erica; Moore, Richard A.; Schweizer, Herbert P.; Woods, Donald E.; Bowlin, Terry L.

2011-01-01

262

DNA binding site analysis of Burkholderia thailandensis response regulators Kristy L. Nowak-Lovato a  

E-print Network

pathogen Burkholderia pseudomallei at locus BPSS2315. We further demonstrate RR binding of predictedDNA binding site analysis of Burkholderia thailandensis response regulators Kristy L. Nowak Keywords: Response regulator Protein-binding microarray Promoter binding site Burkholderia Two component

Bulyk, Martha L.

263

Elucidation of the Regulon and cis-Acting Regulatory Element of HrpB, the AraC-Type Regulator of a Plant Pathogen-Like Type III Secretion System in Burkholderia pseudomallei?†  

PubMed Central

The human pathogen Burkholderia pseudomallei possesses multiple type III secretion system (T3SS) gene clusters. One of these, the B. pseudomallei T3SS2 (T3SS2bp) gene cluster, which apparently plays no role in animal virulence, is also found in six additional Burkholderia spp. and is very similar to T3SSs found in phytopathogenic Xanthomonas spp. and Ralstonia solanacearum. The T3SS2bp gene cluster also encodes an AraC-type regulatory protein (HrpBbp) that is an ortholog of HrpB, the master regulator of the R. solanacearum T3SS (T3SSrso) and its secreted effectors. Transcriptome analysis showed that HrpBbp activates the expression of T3SS2bp genes, as well as their orthologs in R. solanacearum. In addition to activating T3SS2bp, HrpBbp also upregulates the expression of ?30 additional B. pseudomallei genes, including some that may confer production of adhesive pili, a polyketide toxin, several putative T3SS2bp-secreted effectors, and components of a regulatory cascade. T3SS2bp promoter regions were found to contain a conserved DNA motif (p2bp box) identical in sequence and position to the hrpII box required for HrpB-dependent T3SSrso transcription activation. The p2bp box is also present in the promoter regions of the essentially identical T3SS found in the very closely related species Burkholderia thailandensis (T3SS2bt). Analysis of p2bp box mutants showed that it is essential for HrpBbp-mediated transcription activation in both species. Although it has been suggested that T3SS2bp and T3SS2bt may function in phytopathogenicity, we were unable to demonstrate a phytopathogenic phenotype for B. thailandensis in three different plant hosts. PMID:21335458

Lipscomb, Lyla; Schell, Mark A.

2011-01-01

264

Development of an acute model of inhalational melioidosis in the common marmoset (Callithrix jacchus)  

PubMed Central

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 LD50 determination was not possible. The model was further characterized using a target challenge dose of approximately 102 cfu. A separate pathogenesis time-course experiment was also conducted. All animals succumbed, between 27 and 78 h postchallenge. The challenge dose received and the time to the humane endpoint (1 °C below normal body temperature postfever) were correlated. The first indicator of disease was an increased core body temperature (Tc), at 22 h postchallenge. This coincided with bacteraemia and bacterial dissemination. Overt clinical signs were first observed 3–5 h later. A sharp decrease (typically within 3–6 h) in the Tc was observed prior to humanely culling the animals in the lethality study. Pathology was noted in the lung, liver and spleen. Disease progression in the common marmoset appears to be consistent with human infection in terms of bacterial spread, pathology and physiology. The common marmoset can therefore be considered a suitable animal model for further studies of inhalational melioidosis. PMID:22122591

Nelson, Michelle; Dean, Rachel E; Salguero, Francisco J; Taylor, Christopher; Pearce, Peter C; Simpson, Andrew J H; Lever, Mark S

2011-01-01

265

Burkholderia thailandensis Is Virulent in Drosophila melanogaster  

PubMed Central

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, which possesses only an innate immune system, B. thailandensis is highly virulent, causing rapid death when injected or fed. One intriguing aspect of this infection is its temperature dependence: infected flies maintained at 25°C exhibit rapid bacterial proliferation and death in a few days, while infected animals maintained at 18°C exhibit very slow bacterial proliferation and take weeks to die; this effect is due in part to differences in immune activity of the host. Death in this infection is likely due at least in part to a secreted toxin, as injection of flies with sterile B. thailandensis-conditioned medium is able to kill. B. thailandensis infection strongly induces the expression of antimicrobial peptides, but this is insufficient to inhibit bacterial proliferation in infected flies. Finally, the function of fly phagocytes is not affected by B. thailandensis infection. The high virulence of B. thailandensis in the fly suggests the possibility that this organism is a natural pathogen of one or more invertebrates. PMID:23209596

Pilátová, Martina; Dionne, Marc S.

2012-01-01

266

Whole-Genome Assemblies of 56 Burkholderia Species  

PubMed Central

Burkholderia is a genus of betaproteobacteria that includes three notable human pathogens: B. cepacia, B. pseudomallei, and B. mallei. While B. pseudomallei and B. mallei are considered potential biowarfare agents, B. cepacia infections are largely limited to cystic fibrosis patients. Here, we present 56 Burkholderia genomes from 8 distinct species. PMID:25414490

Daligault, H. E.; Davenport, K. W.; Minogue, T. D.; Bishop-Lilly, K. A.; Broomall, S. M.; Bruce, D. C.; Chain, P. S.; Coyne, S. R.; Frey, K. G.; Gibbons, H. S.; Jaissle, J.; Koroleva, G. I.; Ladner, J. T.; Lo, C.-C.; Munk, C.; Palacios, G. F.; Redden, C. L.; Rosenzweig, C. N.; Scholz, M. B.

2014-01-01

267

Whole-genome assemblies of 56 burkholderia species.  

PubMed

Burkholderia is a genus of betaproteobacteria that includes three notable human pathogens: B. cepacia, B. pseudomallei, and B. mallei. While B. pseudomallei and B. mallei are considered potential biowarfare agents, B. cepacia infections are largely limited to cystic fibrosis patients. Here, we present 56 Burkholderia genomes from 8 distinct species. PMID:25414490

Daligault, H E; Davenport, K W; Minogue, T D; Bishop-Lilly, K A; Broomall, S M; Bruce, D C; Chain, P S; Coyne, S R; Frey, K G; Gibbons, H S; Jaissle, J; Koroleva, G I; Ladner, J T; Lo, C-C; Munk, C; Palacios, G F; Redden, C L; Rosenzweig, C N; Scholz, M B; Johnson, S L

2014-01-01

268

SpeI restriction enzyme displays greater discriminatory power than XbaI enzyme does in a pulsed-field gel electrophoresis study on 146 clinical Burkholderia pseudomallei isolates.  

PubMed

Restriction enzymes SpeI and XbaI were used in a pulsed-field gel electrophoresis (PFGE) study for molecular characterization of 146 clinical Burkholderia pseudomallei isolates. The PFGE parameters were optimized to enable comparable, reproducible, and robust results. The optimized parameters for both SpeI and XbaI restriction enzymes used in this study were 200 V and a pulse time of 5 to 65 s for a 28-h runtime. Using SpeI, 9 different clusters were identified, whereas 6 clusters were identified by XbaI digestion, which exhibited 85% similarity to SpeI. SpeI (discrimination index [D]=0.854) showed higher discriminatory power than XbaI did (D=0.464). PMID:21617308

Chua, Kek Heng; See, Kah Heng; Thong, Kwai Lin; Puthucheary, S D

2011-01-01

269

Sequence-Defined Transposon Mutant Library of Burkholderia thailandensis  

PubMed Central

ABSTRACT We constructed a near-saturation transposon mutant library for Burkholderia thailandensis, a low-virulence surrogate for the causative agent of melioidosis (Burkholderia pseudomallei). A primary set of nearly 42,000 unique mutants (~7.5 mutants/gene) was generated using transposon Tn5 derivatives. The strains carry insertions in 87% of the predicted protein-coding genes of the organism, corresponding to nearly all of those nonessential for growth on nutrient agar. To achieve high genome coverage, we developed procedures for efficient sequence identification of insertions in extremely GC-rich regions of DNA. To facilitate strain distribution, we created a secondary library with two mutants per gene for which most transposon locations had been confirmed by resequencing. A map of mutations in the two-allele library and procedures for obtaining strains can be found at http://tools.nwrce.org/tn_mutants/ and http://www.gs.washington.edu/labs/manoil/. The library should facilitate comprehensive mutant screens and serve as a source of strains to test predicted genotype-phenotype associations. PMID:24194535

Gallagher, Larry A.; Ramage, Elizabeth; Patrapuvich, Rapatbhorn; Weiss, Eli; Brittnacher, Mitch; Manoil, Colin

2013-01-01

270

Characterization of cellular immune response and innate immune signaling in human and nonhuman primate primary mononuclear cells exposed to Burkholderia mallei.  

PubMed

Burkholderia pseudomallei infection causes melioidosis and is often characterized by severe sepsis. Although rare in humans, Burkholderia mallei has caused infections in laboratory workers, and the early innate cellular response to B. mallei in human and nonhuman primates has not been characterized. In this study, we examined the primary cellular immune response to B. mallei in PBMC cultures of non-human primates (NHPs), Chlorocebus aethiops (African Green Monkeys), Macaca fascicularis (Cynomolgus macaque), and Macaca mulatta (Rhesus macaque) and humans. Our results demonstrated that B. mallei elicited strong primary pro-inflammatory cytokines (IFN-?, TNF-?, IL-1?, and IL-6) equivalent to the levels of B. pseudomallei in primary PBMC cultures of NHPs and humans. When we examined IL-1? and other cytokine responses by comparison to Escherichia coli LPS, African Green Monkeys appears to be most responsive to B. mallei than Cynomolgus or Rhesus. Characterization of the immune signaling mechanism for cellular response was conducted by using a ligand induced cell-based reporter assay, and our results demonstrated that MyD88 mediated signaling contributed to the B. mallei and B. pseudomallei induced pro-inflammatory responses. Notably, the induced reporter activity with B. mallei, B. pseudomallei, or purified LPS from these pathogens was inhibited and cytokine production was attenuated by a MyD88 inhibitor. Together, these results show that in the scenario of severe hyper-inflammatory responses to B. mallei infection, MyD88 targeted therapeutic intervention may be a successful strategy for therapy. PMID:25450887

Alam, Shahabuddin; Amemiya, Kei; Bernhards, Robert C; Ulrich, Robert G; Waag, David M; Saikh, Kamal U

2015-01-01

271

Melioidosis Diagnostic Workshop, 20131  

PubMed Central

Melioidosis is a severe disease that can be difficult to diagnose because of its diverse clinical manifestations and a lack of adequate diagnostic capabilities for suspected cases. There is broad interest in improving detection and diagnosis of this disease not only in melioidosis-endemic regions but also outside these regions because melioidosis may be underreported and poses a potential bioterrorism challenge for public health authorities. Therefore, a workshop of academic, government, and private sector personnel from around the world was convened to discuss the current state of melioidosis diagnostics, diagnostic needs, and future directions. PMID:25626057

AuCoin, David; Baccam, Prasith; Baggett, Henry C.; Baird, Rob; Bhengsri, Saithip; Blaney, David D.; Brett, Paul J.; Brooks, Timothy J.G.; Brown, Katherine A.; Chantratita, Narisara; Cheng, Allen C.; Dance, David A.B.; Decuypere, Saskia; Defenbaugh, Dawn; Gee, Jay E.; Houghton, Raymond; Jorakate, Possawat; Lertmemongkolchai, Ganjana; Limmathurotsakul, Direk; Merlin, Toby L.; Mukhopadhyay, Chiranjay; Norton, Robert; Peacock, Sharon J.; Rolim, Dionne B.; Simpson, Andrew J.; Steinmetz, Ivo; Stoddard, Robyn A.; Stokes, Martha M.; Sue, David; Tuanyok, Apichai; Whistler, Toni; Wuthiekanun, Vanaporn; Walke, Henry T.

2015-01-01

272

Common TLR1 Genetic Variation Is Not Associated with Death from Melioidosis, a Common Cause of Sepsis in Rural Thailand  

PubMed Central

Melioidosis, infection caused by the Gram-negative bacterium Burkholderia pseudomallei, is a common cause of sepsis in northeast Thailand. In white North Americans, common functional genetic variation in TLR1 is associated with organ failure and death from sepsis. We hypothesized that TLR1 variants would be associated with outcomes in Thais with melioidosis. We collated the global frequencies of three TLR1 variants that are common in white North American populations: rs5743551 (-7202A/G), rs4833095 (742A/G), and rs5743618 (1804G/T). We noted a reversal of the minor allele from white North American subjects to Asian populations that was particularly pronounced for rs5743618. In the Utah residents of European ancestry, the frequency of the rs5743618 T allele was 17% whereas in Vietnamese subjects the frequency was >99%. We conducted a genetic association study in 427 patients with melioidosis to determine the association of TLR1 variation with organ failure or death. We genotyped rs5743551 and rs4833095. The variants were in high linkage disequilibrium but neither variant was associated with organ failure or in-hospital death. In 300 healthy Thai individuals we further tested the association of TLR1 variation with ex vivo blood responses to Pam3CSK4, a TLR1 agonist. Neither variant was robustly associated with blood cytokine responses induced by Pam3CSK4. We identified additional common variation in TLR1 by searching public databases and the published literature and screened three additional TLR1 variants for associations with Pam3CSK4-induced responses but found none. We conclude that the genetic architecture of TLR1 variation differs substantially in southeast Asians compared to other populations and common variation in TLR1 in Thais is not associated with outcome from melioidosis or with altered blood responses to Pam3CSK4. Our findings highlight the need for additional studies of TLR1 and other innate immune genetic modulators of the inflammatory host response and determinants of sepsis in southeast Asian populations. PMID:24392083

Chantratita, Narisara; Tandhavanant, Sarunporn; Myers, Nicolle D.; Chierakul, Wirongrong; Wuthiekanun, Vanaporn; Mahavanakul, Weera; Limmathurotsakul, Direk; Peacock, Sharon J.; West, T. Eoin

2014-01-01

273

Novel Burkholderia mallei Virulence Factors Linked to Specific Host-Pathogen Protein  

E-print Network

, a disease primarily affecting horses but transmittable to humans; and Burkholderia pseudomallei, whichNovel Burkholderia mallei Virulence Factors Linked to Specific Host-Pathogen Protein Interactions Townsend§, Chenggang Yu, Xueping Yu, David DeShazer¶, Jaques Reifman , and Anders Wallqvist Burkholderia

274

Hindawi Publishing Corporation Journal of Biomedicine and Biotechnology  

E-print Network

that are path- ogenic, Burkholderia pseudomallei is the causative agent for Melioidosis, and B. mallei Pathogen Burkholderia vietnamiensis Using Protein Fractionations and Mass Spectrometry Samanthi a more extensive coverage of the Burkholderia vietnamiensis proteome than previously reported

Wysocki, Vicki H.

275

Thoracic melioidosis: A diagnostic dilemma.  

PubMed

The diagnosis of melioidosis can be difficult, and it is frequently described as "the great mimicker". We report a case of thoracic melioidosis presenting as a mediastinal mass with impending superior vena cava obstruction. With the presumptive diagnosis of mediastinal tumor, the patient underwent surgery for tissue sampling, and a purulent collection was found. The clinical syndromes of melioidosis and the diagnostic dilemma are discussed. PMID:24585290

Ashraf, Omer; Iyer, Anand; Krishnan, Ramya; Yadav, Sumit

2015-02-01

276

Isolation of Pseudomonas pseudomallei from soil in north-eastern Thailand  

Microsoft Academic Search

In order to optimize the recovery from soil of Pseudomonas pseudomallei, the cause of melioidosis, 3 selective broths were compared. A basal salt solution containing l-threonine (TBSS) performed significantly better than trypticase soy broth containing crystal violet and colistin 50 mg\\/L (CVC50), both in isolation rate and suppression of overgrowth of other organisms, but the addition of colistin to TBSS

Vanaporn Wuthiekanun; Michael D. Smith; David A. B. Dance; Nicholas J. White

1995-01-01

277

Melioidosis masquerading as enteric fever.  

PubMed

Melioidosis is endemic in Southeast Asia and northern Australia, but it has been rarely reported from India. Recent reports have shown that melioidosis is an emerging infection in this part of the world, but enteric fever is more commonly seen in India. We present a 50-year-old male with diabetes who presented with acute onset of febrile illness. Preliminary investigations were suggestive of enteric fever, and he showed a partial response to parenteral ceftriaxone; however, it later turned out that he had melioidosis. The widal titres were persistently elevated even following treatment with meropenem. PMID:19121671

Valsalan, Rohith; Seshadri, Shubha; Pandit, Vinay R

2008-12-01

278

Melioidosis in a returned traveller  

PubMed Central

Melioidosis is an infection endemic to Southeast Asia and Northern Australia, and is associated with significant morbidity and mortality. The present report describes a case of chronic melioidosis in a returning traveller from the Philippines. Clinical suspicion of this illness is warranted in individuals with a history of travel to endemic regions. Safety in handling clinical specimens is paramount because laboratory transmission has been described. PMID:25285129

Chagla, Zain; Aleksova, Natasha; Quirt, Jaclyn; Emery, Joel; Kraeker, Christian; Haider, Shariq

2014-01-01

279

The Treatment of Melioidosis  

PubMed Central

Melioidosis is a complex bacterial infection, treatment of which combines the urgency of treating rapidly fatal Gram negative septicaemia with the need for eradication of long-term persistent disease in pulmonary, soft tissue, skeletal and other organ systems. Incremental improvements in treatment have been made as a result of multicentre collaboration across the main endemic region of Southeast Asia and northern Australia. There is an emerging consensus on the three main patterns of antimicrobial chemotherapy; initial (Phase 1) treatment, subsequent eradication (Phase 2) therapy and most recently post-exposure (Phase 0) prophylaxis. The combination of agents used, duration of therapy and need for adjunct modalities depends on the type, severity and antimicrobial susceptibility of infection. New antibiotic and adjunct therapies are at an investigational stage but on currently available data are unlikely to make a significant impact on this potentially fatal infection.

Inglis, Timothy J.J.

2010-01-01

280

Fatal melioidosis in goats in Bangkok, Thailand.  

PubMed

Bangkok, Thailand, is a city considered to be at low risk for melioidosis. We describe 10 goats that died of melioidosis in Bangkok. Half of them were born and reared in the city. Multilocus sequence typing ruled out an outbreak. This finding challenges the assumption that melioidosis is rarely acquired in central Thailand. PMID:24891468

Tonpitak, Walaiporn; Sornklien, Chulabha; Chawanit, Mongkol; Pavasutthipaisit, Suvarin; Wuthiekanun, Vanaporn; Hantrakun, Viriya; Amornchai, Premjit; Thaipadungpanit, Janjira; Day, Nicholas P J; Yingst, Samuel; Peacock, Sharon J; Limmathurotsakul, Direk

2014-08-01

281

Cutaneous melioidosis in a healthy Danish man after travelling to South-East Asia.  

PubMed

A healthy Danish man presented with infected prepatellar bursitis 8?months after being involved in a car accident in Malaysia resulting in exposure of a laceration of his knee to stagnant water. Tissue samples grew Burkholderia pseudomallei and diagnostic work up revealed no secondary foci. The patient was successfully treated with surgical debridement and 3?months of oral trimethoprim-sulfamethoxazole. At 6?months follow-up the patient was without relapse. PMID:25596295

Bodilsen, Jacob; Langgaard, Henrik; Nielsen, Hans Linde

2015-01-01

282

Molecular signatures and phylogenomic analysis of the genus Burkholderia: proposal for division of this genus into the emended genus Burkholderia containing pathogenic organisms and a new genus Paraburkholderia gen. nov. harboring environmental species.  

PubMed

The genus Burkholderia contains large number of diverse species which include many clinically important organisms, phytopathogens, as well as environmental species. However, currently, there is a paucity of biochemical or molecular characteristics which can reliably distinguish different groups of Burkholderia species. We report here the results of detailed phylogenetic and comparative genomic analyses of 45 sequenced species of the genus Burkholderia. In phylogenetic trees based upon concatenated sequences for 21 conserved proteins as well as 16S rRNA gene sequence based trees, members of the genus Burkholderia grouped into two major clades. Within these main clades a number of smaller clades including those corresponding to the clinically important Burkholderia cepacia complex (BCC) and the Burkholderia pseudomallei groups were also clearly distinguished. Our comparative analysis of protein sequences from Burkholderia spp. has identified 42 highly specific molecular markers in the form of conserved sequence indels (CSIs) that are uniquely found in a number of well-defined groups of Burkholderia spp. Six of these CSIs are specific for a group of Burkholderia spp. (referred to as Clade I in this work) which contains all clinically relevant members of the genus (viz. the BCC and the B. pseudomallei group) as well as the phytopathogenic Burkholderia spp. The second main clade (Clade II), which is composed of environmental Burkholderia species, is also distinguished by 2 identified CSIs that are specific for this group. Additionally, our work has also identified multiple CSIs that serve to clearly demarcate a number of smaller groups of Burkholderia spp. including 3 CSIs that are specific for the B. cepacia complex, 4 CSIs that are uniquely found in the B. pseudomallei group, 5 CSIs that are specific for the phytopathogenic Burkholderia spp. and 22 other CSI that distinguish two groups within Clade II. The described molecular markers provide highly specific means for the demarcation of different groups of Burkholderia spp. and they also offer novel and useful targets for the development of diagnostic assays for the clinically important members of the BCC or the pseudomallei groups. Based upon the results of phylogenetic analyses, the identified CSIs and the pathogenicity profile of Burkholderia species, we are proposing a division of the genus Burkholderia into two genera. In this new proposal, the emended genus Burkholderia will correspond to the Clade I and it will contain only the clinically relevant and phytopathogenic Burkholderia species. All other Burkholderia spp., which are primarily environmental, will be transferred to a new genus Paraburkholderia gen. nov. PMID:25566316

Sawana, Amandeep; Adeolu, Mobolaji; Gupta, Radhey S

2014-01-01

283

Molecular signatures and phylogenomic analysis of the genus Burkholderia: proposal for division of this genus into the emended genus Burkholderia containing pathogenic organisms and a new genus Paraburkholderia gen. nov. harboring environmental species  

PubMed Central

The genus Burkholderia contains large number of diverse species which include many clinically important organisms, phytopathogens, as well as environmental species. However, currently, there is a paucity of biochemical or molecular characteristics which can reliably distinguish different groups of Burkholderia species. We report here the results of detailed phylogenetic and comparative genomic analyses of 45 sequenced species of the genus Burkholderia. In phylogenetic trees based upon concatenated sequences for 21 conserved proteins as well as 16S rRNA gene sequence based trees, members of the genus Burkholderia grouped into two major clades. Within these main clades a number of smaller clades including those corresponding to the clinically important Burkholderia cepacia complex (BCC) and the Burkholderia pseudomallei groups were also clearly distinguished. Our comparative analysis of protein sequences from Burkholderia spp. has identified 42 highly specific molecular markers in the form of conserved sequence indels (CSIs) that are uniquely found in a number of well-defined groups of Burkholderia spp. Six of these CSIs are specific for a group of Burkholderia spp. (referred to as Clade I in this work) which contains all clinically relevant members of the genus (viz. the BCC and the B. pseudomallei group) as well as the phytopathogenic Burkholderia spp. The second main clade (Clade II), which is composed of environmental Burkholderia species, is also distinguished by 2 identified CSIs that are specific for this group. Additionally, our work has also identified multiple CSIs that serve to clearly demarcate a number of smaller groups of Burkholderia spp. including 3 CSIs that are specific for the B. cepacia complex, 4 CSIs that are uniquely found in the B. pseudomallei group, 5 CSIs that are specific for the phytopathogenic Burkholderia spp. and 22 other CSI that distinguish two groups within Clade II. The described molecular markers provide highly specific means for the demarcation of different groups of Burkholderia spp. and they also offer novel and useful targets for the development of diagnostic assays for the clinically important members of the BCC or the pseudomallei groups. Based upon the results of phylogenetic analyses, the identified CSIs and the pathogenicity profile of Burkholderia species, we are proposing a division of the genus Burkholderia into two genera. In this new proposal, the emended genus Burkholderia will correspond to the Clade I and it will contain only the clinically relevant and phytopathogenic Burkholderia species. All other Burkholderia spp., which are primarily environmental, will be transferred to a new genus Paraburkholderia gen. nov. PMID:25566316

Sawana, Amandeep; Adeolu, Mobolaji; Gupta, Radhey S.

2014-01-01

284

Antibacterial activity of a lectin-like Burkholderia cenocepacia protein  

PubMed Central

Abstract Bacteriocins of the LlpA family have previously been characterized in the ?-proteobacteria Pseudomonas and Xanthomonas. These proteins are composed of two MMBL (monocot mannose-binding lectin) domains, a module predominantly and abundantly found in lectins from monocot plants. Genes encoding four different types of LlpA-like proteins were identified in genomes from strains belonging to the Burkholderia cepacia complex (Bcc) and the Burkholderia pseudomallei group. A selected recombinant LlpA-like protein from the human isolate Burkholderia cenocepacia AU1054 displayed narrow-spectrum genus-specific antibacterial activity, thus representing the first functionally characterized bacteriocin within this ?-proteobacterial genus. Strain-specific killing was confined to other members of the Bcc, with mostly Burkholderia ambifaria strains being susceptible. In addition to killing planktonic cells, this bacteriocin also acted as an antibiofilm agent. Bacteriocins mediate highly selective antagonism among closely related bacteria but such antimicrobial proteins have not yet been reported in Burkholderia. We identified a lectin-like protein of the LlpA family in a Burkholderia cenocepacia human isolate that strain-specifically and selectively kills planktonic and biofilm cells of other Burkholderia cepacia complex members. PMID:23737242

Ghequire, Maarten G K; Canck, Evelien; Wattiau, Pierre; Winge, Iris; Loris, Remy; Coenye, Tom; Mot, René

2013-01-01

285

Phylogenetic analysis of burkholderia species by multilocus sequence analysis.  

PubMed

Burkholderia comprises more than 60 species of environmental, clinical, and agro-biotechnological relevance. Previous phylogenetic analyses of 16S rRNA, recA, gyrB, rpoB, and acdS gene sequences as well as genome sequence comparisons of different Burkholderia species have revealed two major species clusters. In this study, we undertook a multilocus sequence analysis of 77 type and reference strains of Burkholderia using atpD, gltB, lepA, and recA genes in combination with the 16S rRNA gene sequence and employed maximum likelihood and neighbor-joining criteria to test this further. The phylogenetic analysis revealed, with high supporting values, distinct lineages within the genus Burkholderia. The two large groups were named A and B, whereas the B. rhizoxinica/B. endofungorum, and B. andropogonis groups consisted of two and one species, respectively. The group A encompasses several plant-associated and saprophytic bacterial species. The group B comprises the B. cepacia complex (opportunistic human pathogens), the B. pseudomallei subgroup, which includes both human and animal pathogens, and an assemblage of plant pathogenic species. The distinct lineages present in Burkholderia suggest that each group might represent a different genus. However, it will be necessary to analyze the full set of Burkholderia species and explore whether enough phenotypic features exist among the different clusters to propose that these groups should be considered separate genera. PMID:23404651

Estrada-de los Santos, Paulina; Vinuesa, Pablo; Martínez-Aguilar, Lourdes; Hirsch, Ann M; Caballero-Mellado, Jesús

2013-07-01

286

Fatal Co-Infection–Melioidosis and Leptospirosis  

PubMed Central

Co-infection of melioidosis and leptospirosis is uncommon. We report here four such cases, confirmed by blood culture for melioidosis and blood polymerase-chain reaction for leptospirosis, which occurred among rescuers involved in a search and rescue operation for a young man who was suspected to have drowned in Lubuk Yu, a recreational forest in Pahang, Malaysia. Despite treatment, three of the patients died from the co-infection. PMID:22826499

Hin, How Soon; Ramalingam, Rajalingam; Chunn, Kuan Yeh; Ahmad, Norazah; Ab Rahman, Jamalludin; Mohamed, Mohd Sapian

2012-01-01

287

Human melioidosis: an emerging medical problem  

Microsoft Academic Search

Summary Human melioidosis is endemic in South East Asia and tropical Australia. However, increasing numbers of case reports are coming from other parts of the world. Increasing world travel and the potential for person-to-person infection in non-endemic areas make the likelihood of physicians and medical microbiologists encountering the disease far greater than heretofore. Both the disease, melioidosis, and the causative

C. J. Smith; J. C. Allen; M. Noor Embi; O. Othmant; N. Razakt; G. Ismail

1987-01-01

288

40 CFR 725.1075 - Burkholderia cepacia complex.  

Code of Federal Regulations, 2010 CFR

...nine species, Burkholderia cepacia, Burkholderia multivorans...Burkholderia pyrrocinia, Burkholderia cepacia genomovar VIII (Burkholderia anthina ), and Burkholderia cepacia genomovars III and VI are...subsurface groundwater. (b) [Reserved] [68 FR...

2010-07-01

289

Cytidine derivatives as IspF inhibitors of Burkolderia pseudomallei.  

PubMed

Published biological data suggest that the methyl erythritol phosphate (MEP) pathway, a non-mevalonate isoprenoid biosynthetic pathway, is essential for certain bacteria and other infectious disease organisms. One highly conserved enzyme in the MEP pathway is 2C-methyl-d-erythritol 2,4-cyclodiphosphate synthase (IspF). Fragment-bound complexes of IspF from Burkholderia pseudomallei were used to design and synthesize a series of molecules linking the cytidine moiety to different zinc pocket fragment binders. Testing by surface plasmon resonance (SPR) found one molecule in the series to possess binding affinity equal to that of cytidine diphosphate, despite lacking any metal-coordinating phosphate groups. Close inspection of the SPR data suggest different binding stoichiometries between IspF and test compounds. Crystallographic analysis shows important variations between the binding mode of one synthesized compound and the pose of the bound fragment from which it was designed. The binding modes of these molecules add to our structural knowledge base for IspF and suggest future refinements in this compound series. PMID:24157367

Zhang, Zheng; Jakkaraju, Sriram; Blain, Joy; Gogol, Kenneth; Zhao, Lei; Hartley, Robert C; Karlsson, Courtney A; Staker, Bart L; Edwards, Thomas E; Stewart, Lance J; Myler, Peter J; Clare, Michael; Begley, Darren W; Horn, James R; Hagen, Timothy J

2013-12-15

290

DNA-Based Diagnostic Approaches for Identification of Burkholderia cepacia Complex, Burkholderia vietnamiensis, Burkholderia multivorans, Burkholderia stabilis, and Burkholderia cepacia Genomovars I and III  

Microsoft Academic Search

Bacteria of the Burkholderia cepacia complex consist of five discrete genomic species, including genomovars I and III and three new species: Burkholderia multivorans (formerly genomovar II), Burkholderia stabilis (formerly genomovar IV), and Burkholderia vietnamiensis (formerly genomovar V). Strains of all five genomo- vars are capable of causing opportunistic human infection, and microbiological identification of these closely related species is difficult.

ESHWAR MAHENTHIRALINGAM; JOCELYN BISCHOF; SEAN K. BYRNE; CHRISTOPHER RADOMSKI; JULIAN E. DAVIES; YOSSEF AV-GAY

291

Management of melioidosis osteomyelitis and septic arthritis.  

PubMed

Little information is available about several important aspects of the treatment of melioidosis osteomyelitis and septic arthritis. We undertook a retrospective review of 50 patients with these conditions in an attempt to determine the effect of location of the disease, type of surgical intervention and duration of antibiotic treatment on outcome, particularly complications and relapse. We found that there was a 27.5% risk of osteomyelitis of the adjacent bone in patients with septic arthritis in the lower limb. Patients with septic arthritis and osteomyelitis of an adjacent bone were in hospital significantly longer (p = 0.001), needed more operations (p = 0.031) and had a significantly higher rate of complications and re-presentation (p = 0.048). More than half the patients (61%), most particularly those with multifocal bone and joint involvement, and those with septic arthritis and osteomyelitis of an adjacent bone who were treated operatively, needed more visits to theatre. Cite this article: Bone Joint J 2015;97-B:277-82. PMID:25628295

Shetty, R P; Mathew, M; Smith, J; Morse, L P; Mehta, J A; Currie, B J

2015-02-01

292

Quorum-Sensing Control of Antibiotic Synthesis in Burkholderia thailandensis?  

PubMed Central

The genome of Burkholderia thailandensis codes for several LuxR-LuxI quorum-sensing systems. We used B. thailandensis quorum-sensing deletion mutants and recombinant Escherichia coli to determine the nature of the signals produced by one of the systems, BtaR2-BtaI2, and to show that this system controls genes required for the synthesis of an antibiotic. BtaI2 is an acyl-homoserine lactone (acyl-HSL) synthase that produces two hydroxylated acyl-HSLs, N-3-hydroxy-decanoyl-HSL (3OHC10-HSL) and N-3-hydroxy-octanoyl-HSL (3OHC8-HSL). The btaI2 gene is positively regulated by BtaR2 in response to either 3OHC10-HSL or 3OHC8-HSL. The btaR2-btaI2 genes are located within clusters of genes with annotations that suggest they are involved in the synthesis of polyketide or peptide antibiotics. Stationary-phase cultures of wild-type B. thailandensis, but not a btaR2 mutant or a strain deficient in acyl-HSL synthesis, produced an antibiotic effective against gram-positive bacteria. Two of the putative antibiotic synthesis gene clusters require BtaR2 and either 3OHC10-HSL or 3OHC8-HSL for activation. This represents another example where antibiotic synthesis is controlled by quorum sensing, and it has implications for the evolutionary divergence of B. thailandensis and its close relatives Burkholderia pseudomallei and Burkholderia mallei. PMID:19376863

Duerkop, Breck A.; Varga, John; Chandler, Josephine R.; Peterson, Snow Brook; Herman, Jake P.; Churchill, Mair E. A.; Parsek, Matthew R.; Nierman, William C.; Greenberg, E. Peter

2009-01-01

293

Insights into ?-lactamases from Burkholderia species, two phylogenetically related yet distinct resistance determinants.  

PubMed

Burkholderia cepacia complex and Burkholderia pseudomallei are opportunistic human pathogens. Resistance to ?-lactams among Burkholderia spp. is attributable to expression of ?-lactamases (e.g. PenA in B. cepacia complex and PenI in B. pseudomallei). Phylogenetic comparisons reveal that PenA and PenI are highly related. However, the analyses presented here reveal that PenA is an inhibitor-resistant carbapenemase, most similar to KPC-2 (the most clinically significant serine carbapenemase), whereas PenI is an extended spectrum ?-lactamase. PenA hydrolyzes ?-lactams with k(cat) values ranging from 0.38 ± 0.04 to 460 ± 46 s(-1) and possesses high k(cat)/k(inact) values of 2000, 1500, and 75 for ?-lactamase inhibitors. PenI demonstrates the highest kcat value for cefotaxime of 9.0 ± 0.9 s(-1). Crystal structure determination of PenA and PenI reveals important differences that aid in understanding their contrasting phenotypes. Changes in the positioning of conserved catalytic residues (e.g. Lys-73, Ser-130, and Tyr-105) as well as altered anchoring and decreased occupancy of the deacylation water explain the lower k(cat) values of PenI. The crystal structure of PenA with imipenem docked into the active site suggests why this carbapenem is hydrolyzed and the important role of Arg-220, which was functionally confirmed by mutagenesis and biochemical characterization. Conversely, the conformation of Tyr-105 hindered docking of imipenem into the active site of PenI. The structural and biochemical analyses of PenA and PenI provide key insights into the hydrolytic mechanisms of ?-lactamases, which can lead to the rational design of novel agents against these pathogens. PMID:23658015

Papp-Wallace, Krisztina M; Taracila, Magdalena A; Gatta, Julian A; Ohuchi, Nozomi; Bonomo, Robert A; Nukaga, Michiyoshi

2013-06-28

294

Insights into ?-Lactamases from Burkholderia Species, Two Phylogenetically Related yet Distinct Resistance Determinants*  

PubMed Central

Burkholderia cepacia complex and Burkholderia pseudomallei are opportunistic human pathogens. Resistance to ?-lactams among Burkholderia spp. is attributable to expression of ?-lactamases (e.g. PenA in B. cepacia complex and PenI in B. pseudomallei). Phylogenetic comparisons reveal that PenA and PenI are highly related. However, the analyses presented here reveal that PenA is an inhibitor-resistant carbapenemase, most similar to KPC-2 (the most clinically significant serine carbapenemase), whereas PenI is an extended spectrum ?-lactamase. PenA hydrolyzes ?-lactams with kcat values ranging from 0.38 ± 0.04 to 460 ± 46 s?1 and possesses high kcat/kinact values of 2000, 1500, and 75 for ?-lactamase inhibitors. PenI demonstrates the highest kcat value for cefotaxime of 9.0 ± 0.9 s?1. Crystal structure determination of PenA and PenI reveals important differences that aid in understanding their contrasting phenotypes. Changes in the positioning of conserved catalytic residues (e.g. Lys-73, Ser-130, and Tyr-105) as well as altered anchoring and decreased occupancy of the deacylation water explain the lower kcat values of PenI. The crystal structure of PenA with imipenem docked into the active site suggests why this carbapenem is hydrolyzed and the important role of Arg-220, which was functionally confirmed by mutagenesis and biochemical characterization. Conversely, the conformation of Tyr-105 hindered docking of imipenem into the active site of PenI. The structural and biochemical analyses of PenA and PenI provide key insights into the hydrolytic mechanisms of ?-lactamases, which can lead to the rational design of novel agents against these pathogens. PMID:23658015

Papp-Wallace, Krisztina M.; Taracila, Magdalena A.; Gatta, Julian A.; Ohuchi, Nozomi; Bonomo, Robert A.; Nukaga, Michiyoshi

2013-01-01

295

Global Analysis of the Burkholderia thailandensis Quorum Sensing-Controlled Regulon  

PubMed Central

Burkholderia thailandensis contains three acyl-homoserine lactone quorum sensing circuits and has two additional LuxR homologs. To identify B. thailandensis quorum sensing-controlled genes, we carried out transcriptome sequencing (RNA-seq) analyses of quorum sensing mutants and their parent. The analyses were grounded in the fact that we identified genes coding for factors shown previously to be regulated by quorum sensing among a larger set of quorum-controlled genes. We also found that genes coding for contact-dependent inhibition were induced by quorum sensing and confirmed that specific quorum sensing mutants had a contact-dependent inhibition defect. Additional quorum-controlled genes included those for the production of numerous secondary metabolites, an uncharacterized exopolysaccharide, and a predicted chitin-binding protein. This study provides insights into the roles of the three quorum sensing circuits in the saprophytic lifestyle of B. thailandensis, and it provides a foundation on which to build an understanding of the roles of quorum sensing in the biology of B. thailandensis and the closely related pathogenic Burkholderia pseudomallei and Burkholderia mallei. PMID:24464461

Majerczyk, Charlotte; Brittnacher, Mitchell; Jacobs, Michael; Armour, Christopher D.; Radey, Mathew; Schneider, Emily; Phattarasokul, Somsak; Bunt, Richard

2014-01-01

296

The effect of glibenclamide on the pathogenesis of melioidosis  

E-print Network

, Rattus argentiventor. R. exulans, Rattus exulans. R. rattus, Rattus rattus. R. tionamicus jalorensis, Rattus tionamicus jalorensis. RAW264.7, a cell line originating from virus-transformed mouse monocytes. The cell line sheds murine leukaemia virus... name in 1921, being coined from the Greek melis (distemper of asses) and eidos (resemblance), and refers to its resemblance to glanders, an infection of equids caused by the related organism, B. mallei.9 The history of melioidosis research is punctuated...

Koh, Gavin Christian Kia Wee

2012-03-06

297

Virulence of Burkholderia mallei Quorum-Sensing Mutants  

PubMed Central

Many Proteobacteria use acyl-homoserine lactone-mediated quorum-sensing (QS) to activate specific sets of genes as a function of cell density. QS often controls the virulence of pathogenic species, and in fact a previous study indicated that QS was important for Burkholderia mallei mouse lung infections. To gain in-depth information on the role of QS in B. mallei virulence, we constructed and characterized a mutant of B. mallei strain GB8 that was unable to make acyl-homoserine lactones. The QS mutant showed virulence equal to that of its wild-type parent in an aerosol mouse infection model, and growth in macrophages was indistinguishable from that of the parent strain. Furthermore, we assessed the role of QS in B. mallei ATCC 23344 by constructing and characterizing a mutant strain producing AiiA, a lactonase enzyme that degrades acyl-homoserine lactones. Although acyl-homoserine lactone levels in cultures of this strain are very low, it showed full virulence. Contrary to the previous report, we conclude that QS is not required for acute B. mallei infections of mice. QS may be involved in some stage of chronic infections in the natural host of horses, or the QS genes may be remnants of the QS network in B. pseudomallei from which this host-adapted pathogen evolved. PMID:23429539

Majerczyk, Charlotte; Kinman, Loren; Han, Tony; Bunt, Richard

2013-01-01

298

Genomic characterization of JG068, a novel virulent podovirus active against Burkholderia cenocepacia  

PubMed Central

Background As is true for many other antibiotic-resistant Gram-negative pathogens, members of the Burkholderia cepacia complex (BCC) are currently being assessed for their susceptibility to phage therapy as an antimicrobial treatment. The objective of this study was to perform genomic and limited functional characterization of the novel BCC phage JG068 (vB_BceP_JG068). Results JG068 is a podovirus that forms large, clear plaques on Burkholderia cenocepacia K56-2. Host range analysis indicates that this phage can infect environmental, clinical, and epidemic isolates of Burkholderia multivorans, B. cenocepacia, Burkholderia stabilis, and Burkholderia dolosa, likely through interaction with the host lipopolysaccharide as a receptor. The JG068 chromosome is 41,604 base pairs (bp) in length and is flanked by 216 bp short direct terminal repeats. Gene expression originates from both host and phage promoters and is in the forward direction for all 49 open reading frames. The genome sequence shows similarity to Ralstonia phage ?RSB1, Caulobacter phage Cd1, and uncharacterized genetic loci of blood disease bacterium R229 and Burkholderia pseudomallei 1710b. CoreGenesUniqueGenes analysis indicates that JG068 belongs to the Autographivirinae subfamily and ?KMV-like phages genus. Modules within the genome encode proteins involved in DNA-binding, morphogenesis, and lysis, but none associated with pathogenicity or lysogeny. Similar to the signal-arrest-release (SAR) endolysin of ?KMV, inducible expression of the JG068 SAR endolysin causes lysis of Escherichia coli that is dependent on the presence of an N-terminal signal sequence. In an in vivo assay using the Galleria mellonella infection model, treatment of B. cenocepacia K56-2-infected larvae with JG068 results in a significant increase in larval survival. Conclusions As JG068 has a broad host range, does not encode virulence factors, is obligately lytic, and has activity against an epidemic B. cenocepacia strain in vivo, this phage is a highly promising candidate for BCC phage therapy development. PMID:23978260

2013-01-01

299

CHROMOSOMAL MULTIPLICITY IN BURKHOLDERIA CEPACIA  

EPA Science Inventory

We have used CHEF gel electrophoresis to screen preparations of large DNA from different Burkholderia cepacia isolates for the presence of DNA species corresponding to the linearized forms of the three chromosomes of 3.4,2.5, and 0.9 Mb identified in B. cepacia strain 17616. DNA ...

300

Burkholderia contaminans: unusual cause of biliary sepsis.  

PubMed

We report a case of biliary tract infection caused by a strain of Burkholderia contaminans, a member of the Burkholderia cepacia complex. The patient developed sepsis after endoscopic retrograde cholangiopancreatography (ERCP). Gram-negative bacilli were isolated from blood and bile cultures. Automated bacterial identification systems identified the organism as Burkholderia cepacia, whereas DNA sequence analysis revealed that the recA gene isolate was identical to that of B. contaminans. The patient responded to therapy with the antibiotics trimethoprim/sulfamethoxazole and biliary tract decompression. This case suggests that B. contaminans can be a causative agent of healthcare-associated biliary tract infections such as ERCP-related cholangitis. PMID:23292160

Ohji, Goh; Ohkusu, Kiyofumi; Toguchi, Akihiro; Otsuka, Yoshihito; Hosokawa, Naoto; Iwata, Kentaro

2013-10-01

301

Gene and Protein Expression in Response to Different Growth Temperatures and Oxygen Availability in Burkholderia thailandensis  

PubMed Central

Burkholderia thailandensis, although normally avirulent for mammals, can infect macrophages in vitro and has occasionally been reported to cause pneumonia in humans. It is therefore used as a model organism for the human pathogen B. pseudomallei, to which it is closely related phylogenetically. We characterized the B. thailandensis clinical isolate CDC2721121 (BtCDC272) at the genome level and studied its response to environmental cues associated with human host colonization, namely, temperature and oxygen limitation. Effects of the different growth conditions on BtCDC272 were studied through whole genome transcription studies and analysis of proteins associated with the bacterial cell surface. We found that growth at 37°C, compared to 28°C, negatively affected cell motility and flagella production through a mechanism involving regulation of the flagellin-encoding fliC gene at the mRNA stability level. Growth in oxygen-limiting conditions, in contrast, stimulated various processes linked to virulence, such as lipopolysaccharide production and expression of genes encoding protein secretion systems. Consistent with these observations, BtCDC272 grown in oxygen limitation was more resistant to phagocytosis and strongly induced the production of inflammatory cytokines from murine macrophages. Our results suggest that, while temperature sensing is important for regulation of B. thailandensis cell motility, oxygen limitation has a deeper impact on its physiology and constitutes a crucial environmental signal for the production of virulence factors. PMID:24671187

Peano, Clelia; Chiaramonte, Fabrizio; Motta, Sara; Pietrelli, Alessandro; Jaillon, Sebastien; Rossi, Elio; Consolandi, Clarissa; Champion, Olivia L.; Michell, Stephen L.; Freddi, Luca; Falciola, Luigi; Basilico, Fabrizio; Garlanda, Cecilia; Mauri, Pierluigi; De Bellis, Gianluca; Landini, Paolo

2014-01-01

302

The twin arginine translocation system is essential for aerobic growth and full virulence of Burkholderia thailandensis.  

PubMed

The twin arginine translocation (Tat) system in bacteria is responsible for transporting folded proteins across the cytoplasmic membrane, and in some bacteria, Tat-exported substrates have been linked to virulence. We report here that the Tat machinery is present in Burkholderia pseudomallei, B. mallei, and B. thailandensis, and we show that the system is essential for aerobic but not anaerobic growth. Switching off of the Tat system in B. thailandensis grown anaerobically resulted in filamentous bacteria, and bacteria showed increased sensitivity to some ?-lactam antibiotics. In Galleria mellonella and zebrafish infection models, the Tat conditional mutant was attenuated. The aerobic growth-restricted phenotype indicates that Tat substrates may play a functional role in oxygen-dependent energy conservation. In other bacteria, aerobic growth restriction in Tat mutants has been attributed to the inability to translocate PetA, the Rieske iron-sulfur protein which forms part of the quinol-cytochrome c oxidoreductase complex. Here, we show that PetA is not responsible for aerobic growth restriction in B. thailandensis. However, we have identified an operon encoding 2 proteins of unknown function (BTH_I2176 and BTH_I2175) that play a role in aerobic growth restriction, and we present evidence that BTH_I2176 is Tat translocated. PMID:24214943

Wagley, Sariqa; Hemsley, Claudia; Thomas, Rachael; Moule, Madeleine G; Vanaporn, Muthita; Andreae, Clio; Robinson, Matthew; Goldman, Stan; Wren, Brendan W; Butler, Clive S; Titball, Richard W

2014-01-01

303

Occurrence of Multiple Genomovars of Burkholderia cepacia in Cystic Fibrosis Patients and Proposal of Burkholderia multivorans sp. nov  

Microsoft Academic Search

We performed an integrated genotypic and phenotypic analysis of 128 strains of the genera Burkholderia, Rabtonia, and Pseudomonas in order to study the taxonomic structure of Burkholderia cepacia and its relation- ships with other Burkholderia species. Our data show that presumed B. cepacia strains isolated from cystic fibrosis patients belong to at least five distinct genomic species, one of which

P. VANDAMME; B. HOLMES; M. VANCANNEYT; T. COENYE; B. HOSTE; R. COOPMAN; H. REVETS; S. LAUWERS; M. GILLIS; K. KERSTERS; J. R. W. GOVAN

304

Burkholderia pyrrocinia in cystic fibrosis lung transplantation: a case report.  

PubMed

Infection with Burkholderia species is typically considered a contraindication leading to transplantation in cystic fibrosis (CF). However, the risks posed by different Burkholderia species on transplantation outcomes are poorly defined. We present the case of a patient with CF who underwent lung transplantation due to a severe respiratory failure from chronic airways infection with Burkholderia pyrrocinia (B. cepacia genomovar IX) and pan-resistant Pseudomonas aeruginosa. The postoperative course was complicated by recurrent B. pyrrocinia infections, ultimately lea ding to uncontrollable sepsis and death. This is the first case report in CF of Burkholderia pyrrocinia infection and lung transplantation, providing further evidence of the high risk nature of the Burkholderia species. PMID:24507071

Savi, D; De Biase, R Valerio; Amaddeo, A; Anile, M; Venuta, F; Ruberto, F; Simmonds, N; Cimino, G; Quattrucci, S

2014-01-01

305

Burkholderia cepacia sepsis among neonates.  

PubMed

Burkholderia cepacia is a rare cause of sepsis in newborns and its transmission involves human contact with heavily contaminated medical devices and disinfectants. The authors aimed to determine epidemiology, clinical features, antibiotic sensitivity pattern, complications and outcome of blood culture proven B. cepacia infections in 12 neonates. All neonates were outborn, 5 preterm and 7 term. B. cepacia was isolated from blood in all and concurrently from CSF in three neonates. Lethargy and respiratory distress (41.7 %) were major presenting features. Five newborns (41.7 %) required mechanical ventilation for 3-7 d. Highest bacterial susceptibility was observed for meropenem (100 %), followed by cefoperazone-sulbactam, piperacillin-tazobactam, sulfamethoxazole-trimethoprim (all 83 %), ceftazidime (75 %) and ciprofloxacin (42 %). Piperacillin-tazobactam, ciprofloxacin and cotrimoxazole either singly or in combination led to complete recovery of 11 (91.7 %) newborns; one developed hydrocephalus. Eight of nine infants who completed 6 mo follow up were normal. Prompt recognition and appropriate antibiotic therapy for B. cepacia infection results in complete recovery in majority. PMID:24871076

Patra, Saikat; Bhat Y, Ramesh; Lewis, Leslie Edward; Purakayastha, Jayashree; Sivaramaraju, V Vamsi; Kalwaje E, Vandana; Mishra, Swathi

2014-11-01

306

Burkholderia monticola sp. nov., Isolated from Mountain Soil.  

PubMed

An ivory yellow-colored, gram-negative, short-rod-shaped, aerobic bacterial strain, designated JC2948T, was isolated from a soil sample of Mountain Gwanak, Republic of Korea. 16S rRNA gene sequence analysis indicated that strain JC2948T belongs to the genus Burkholderia. The test strain showed highest sequence similarities to Burkholderia tropica LMG 22274T (97.6%), Burkholderia acidipaludis NBRC 101816T (97.5%), Burkholderia tuberum LMG 21444T (97.5%), Burkholderia sprentiae LMG 27175T (97.4%), Burkholderia terricola LMG 20594T (97.3%) and Burkholderia diazotrophica LMG 26031T (97.1%). Based on average nucleotide identity (ANI) values, the new isolate represents a novel genomic species by showing less than 90% of ANI values with other closely related species. Also other phylosiological and biochemical comparison allowed phenotypic differentiation of strain JC2948T from the members of the genus Burkholderia. Therefore, this strain should be classified as the type strain of a novel Burkholderia species. The name Burkholderia monticola sp. nov. (type strain JC2948T = JCM 19904T = KACC 17924T) is proposed. PMID:25472981

Baek, Inwoo; Seo, Boram; Lee, Imchang; Yi, Hana; Chun, Jongsik

2014-12-01

307

A polar-localized iron-binding protein determines the polar targeting of Burkholderia?BimA autotransporter and actin tail formation.  

PubMed

Intracellular bacterial pathogens including Shigella, Listeria, Mycobacteria, Rickettsia and Burkholderia spp. deploy a specialized surface protein onto one pole of the bacteria to induce filamentous actin tail formation for directional movement within host cytosol. The mechanism underlying polar targeting of the actin tail proteins is unknown. Here we perform a transposon screen in Burkholderia thailandensis and identify a conserved bimC that is required for actin tail formation mediated by BimA from B.?thailandensis and its closely related pathogenic species B.?pseudomallei and B.?mallei. bimC is located upstream of bimA in the same operon. Loss of bimC results in even distribution of BimA on the outer membrane surface, where actin polymerization still occurs. BimC is targeted to the same bacterial pole independently of BimA. BimC confers polar targeting of BimA prior to BimA translocation across bacterial inner membrane. BimC is an iron-binding protein, requiring a four-cysteine cluster at the carboxyl terminus. Mutation of the cysteine cluster disrupts BimC polar localization. Truncation analyses identify the transmembrane domain in BimA being responsible for its polar targeting. Consistently, BimC can interact with BimA transmembrane domain in an iron binding-dependent manner. Our study uncovers a new mechanism that determines the polar distribution of bacteria-induced actin tail in infected host cells. PMID:25293534

Lu, Qiuhe; Xu, Yue; Yao, Qing; Niu, Miao; Shao, Feng

2014-10-01

308

Natural Burkholderia mallei infection in Dromedary, Bahrain.  

PubMed

We confirm a natural infection of dromedaries with glanders. Multilocus variable number tandem repeat analysis of a Burkholderia mallei strain isolated from a diseased dromedary in Bahrain revealed close genetic proximity to strain Dubai 7, which caused an outbreak of glanders in horses in the United Arab Emirates in 2004. PMID:21762586

Wernery, Ulrich; Wernery, Renate; Joseph, Marina; Al-Salloom, Fajer; Johnson, Bobby; Kinne, Joerg; Jose, Shanti; Jose, Sherry; Tappendorf, Britta; Hornstra, Heidie; Scholz, Holger C

2011-07-01

309

Natural Burkholderia mallei Infection in Dromedary, Bahrain  

PubMed Central

We confirm a natural infection of dromedaries with glanders. Multilocus variable number tandem repeat analysis of a Burkholderia mallei strain isolated from a diseased dromedary in Bahrain revealed close genetic proximity to strain Dubai 7, which caused an outbreak of glanders in horses in the United Arab Emirates in 2004. PMID:21762586

Wernery, Ulrich; Wernery, Renate; Joseph, Marina; Al-Salloom, Fajer; Johnson, Bobby; Kinne, Joerg; Jose, Shanti; Jose, Sherry; Tappendorf, Britta; Hornstra, Heidie

2011-01-01

310

Glibenclamide reduces pro-inflammatory cytokine production by neutrophils of diabetes patients in response to bacterial infection  

NASA Astrophysics Data System (ADS)

Type 2 diabetes mellitus is a major risk factor for melioidosis, which is caused by Burkholderia pseudomallei. Our previous study has shown that polymorphonuclear neutrophils (PMNs) from diabetic subjects exhibited decreased functions in response to B. pseudomallei. Here we investigated the mechanisms regulating cytokine secretion of PMNs from diabetic patients which might contribute to patient susceptibility to bacterial infections. Purified PMNs from diabetic patients who had been treated with glibenclamide (an ATP-sensitive potassium channel blocker for anti-diabetes therapy), showed reduction of interleukin (IL)-1? and IL-8 secretion when exposed to B. pseudomallei. Additionally, reduction of these pro-inflammatory cytokines occurred when PMNs from diabetic patients were treated in vitro with glibenclamide. These findings suggest that glibenclamide might be responsible for the increased susceptibility of diabetic patients, with poor glycemic control, to bacterial infections as a result of its effect on reducing IL-1? production by PMNs.

Kewcharoenwong, Chidchamai; Rinchai, Darawan; Utispan, Kusumawadee; Suwannasaen, Duangchan; Bancroft, Gregory J.; Ato, Manabu; Lertmemongkolchai, Ganjana

2013-11-01

311

Role of phages in the pathogenesis of Burkholderia or “Where are the toxin genes in Burkholderia phages?”  

PubMed Central

Summary Most bacteria of the genus Burkholderia are soil- and rhizosphere- associated, noted for their metabolic plasticity in the utilization of a wide range of organic compounds as carbon sources. Many Burkholderia species are also opportunistic human and plant pathogens and the distinction between environmental, plant, and human pathogens is not always clear. Burkholderia phages are not uncommon and multiple cryptic prophages are identifiable in the sequenced Burkholderia genomes. Phages have played a crucial role in the transmission of virulence factors among many important pathogens, however, the data does not yet support a significant correlation between phages and pathogenicity in the Burkholderia. This may be due to the role of Burkholderia as a “versaphile” such that selection is occurring in several niches, including roles as a pathogen and in the context of environmental survival. PMID:17719265

Summer, Elizabeth J.; Gill, Jason J.; Upton, Chris; Gonzalez, Carlos F.; Young, Ry

2007-01-01

312

Comparative metabolic systems analysis of pathogenic Burkholderia.  

PubMed

Burkholderia cenocepacia and Burkholderia multivorans are opportunistic drug-resistant pathogens that account for the majority of Burkholderia cepacia complex infections in cystic fibrosis patients and also infect other immunocompromised individuals. While they share similar genetic compositions, B. cenocepacia and B. multivorans exhibit important differences in pathogenesis. We have developed reconciled genome-scale metabolic network reconstructions of B. cenocepacia J2315 and B. multivorans ATCC 17616 in parallel (designated iPY1537 and iJB1411, respectively) to compare metabolic abilities and contextualize genetic differences between species. The reconstructions capture the metabolic functions of the two species and give insight into similarities and differences in their virulence and growth capabilities. The two reconstructions have 1,437 reactions in common, and iPY1537 and iJB1411 have 67 and 36 metabolic reactions unique to each, respectively. After curating the extensive reservoir of metabolic genes in Burkholderia, we identified 6 genes essential to growth that are unique to iPY1513 and 13 genes uniquely essential to iJB1411. The reconstructions were refined and validated by comparing in silico growth predictions to in vitro growth capabilities of B. cenocepacia J2315, B. cenocepacia K56-2, and B. multivorans ATCC 17616 on 104 carbon sources. Overall, we identified functional pathways that indicate B. cenocepacia can produce a wider array of virulence factors compared to B. multivorans, which supports the clinical observation that B. cenocepacia is more virulent than B. multivorans. The reconciled reconstructions provide a framework for generating and testing hypotheses on the metabolic and virulence capabilities of these two related emerging pathogens. PMID:24163337

Bartell, Jennifer A; Yen, Phillip; Varga, John J; Goldberg, Joanna B; Papin, Jason A

2014-01-01

313

Glutathione deficiency in type 2 diabetes impairs cytokine responses and control of intracellular bacteria  

PubMed Central

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-? induction and poor bacterial killing. The defect was specific to the IL-12–IFN-? axis. Defective IL-12 production was also observed during Mycobacterium tuberculosis infection, in which diabetes is likewise known to be a strong risk factor. In contrast, IL-12 production in diabetic cells was not affected upon Salmonella enterica infection or in response to TLR2, -3, -4, and -5 ligands. Poor IL-12 production correlated with a deficiency in intracellular reduced glutathione (GSH) concentrations in diabetic patients. Addition of GSH or N-acetylcysteine to PBMCs selectively restored IL-12 and IFN-? production and improved bacterial killing. Furthermore, the depletion of GSH in mice led to increased susceptibility to melioidosis, reduced production of IL-12p70, and poorer disease outcome. Our data thus establish a link between GSH deficiency in diabetes and increased susceptibility to melioidosis that may open up new therapeutic avenues to protect diabetic patients against some intracellular bacterial pathogens. PMID:22546856

Tan, Kai Soo; Lee, Kok Onn; Low, Kee Chung; Gamage, Akshamal Mihiranga; Liu, Yichun; Tan, Gek-Yen Gladys; Koh, Hui Qi Vanessa; Alonso, Sylvie; Gan, Yunn-Hwen

2012-01-01

314

Biocide susceptibility of the Burkholderia cepacia complex  

PubMed Central

Objectives The Burkholderia cepacia complex (Bcc) species are important opportunistic pathogens with intrinsic antibiotic resistance. They are also well known as contaminants of disinfectants, yet their biocide susceptibility has not been studied in detail. We investigated Bcc biocide susceptibility and correlated it to their taxonomy, antibiotic susceptibility and ability to form biofilms. Methods Genetically distinct Bcc strains belonging to 12 of the defined species were examined. Biocide susceptibility was assessed by (i) broth dilution MIC assays, (ii) agar growth-based MBC screens and (iii) suspension tests. Antibiotic MIC was determined by Etest® strips, and the ability to form biofilms was examined in a 96-well plate assay. Results Biocide susceptibility varied across the Bcc complex with high MIC recorded for chlorhexidine (>100 mg/L), cetylpyridinium chloride (>200 mg/L), triclosan (>500 mg/L), benzalkonium chloride (>400 mg/L) and povidone (>50?000 mg/L). Species-dependent differences were apparent only for cetylpyridinium chloride. There was no correlation between biocide susceptibility and (i) antibiotic susceptibility or (ii) the ability to form biofilms. Biocide MBC was considerably higher than the MIC (chlorhexidine, 6-fold greater; cetylpyridinium chloride, 20-fold greater). Cystic fibrosis outbreak strains (Burkholderia multivorans Glasgow strain and Burkholderia cenocepacia ET12) possessed elevated chlorhexidine resistance, and Bcc bacteria were also shown to remain viable in current commercial biocide formulations. Conclusions Bcc bacteria are resistant to a wide range of biocides and further representatives of this group should be included as reference strains in the development of new anti-infectives and commercial formulations. PMID:19153076

Rose, Helen; Baldwin, Adam; Dowson, Christopher G.; Mahenthiralingam, Eshwar

2009-01-01

315

Histone Deacetylase Inhibitors from Burkholderia Thailandensis  

PubMed Central

Bioactivity guided fractionation of an extract of Burkholderia thailandensis led to the isolation and identification of a new cytotoxic depsipeptide and its dimer. Both compounds potently inhibited the function of histone deacetylases 1 and 4. The monomer, spiruchostatin C (2), was tested side-by-side with the clinical depsipeptide FK228 (1, Istodax®, romidepsin) in a murine hollow fiber assay consisting of 12 implanted tumor cell lines. Spiruchostatin C (2) showed good activity towards LOX IMVI melanoma cells and NCI-H522 non small cell lung cancer cells. Overall, however, FK228 (1) showed a superior in vivo antitumor profile compared to the new compound. PMID:21967146

Klausmeyer, Paul; Shipley, Suzanne; Zuck, Karina M.; McCloud, Thomas G.

2011-01-01

316

Identification of Pseudomonas pseudomallei in clinical practice: use of simple screening tests and API 20NE  

Microsoft Academic Search

The API 20NE kit and a simple screening system involving Gram's stain, the oxidase reaction, colistin and gentamicin resistance, and colonial characteristics on a differential agar medium, were used to test 400 strains of Pseudomonas pseudomallei. The API kit identified 390 (97.5%) strains correctly on first testing and all but one of the remainder on second testing. Only one strain

D A Dance; V Wuthiekanun; P Naigowit; N J White

1989-01-01

317

Clonally related Burkholderia contaminans among ventilated patients without cystic fibrosis.  

PubMed

We investigated a cluster of 10 Burkholderia cepacia complex-positive cultures among ventilated patients and those with a tracheostomy in an acute care hospital. Isolates from 5 patients had outbreak-strain-related Burkholderia contaminans. Isolates of B. cepacia complex unrelated to the outbreak strain were cultured from a sink drain. The investigation identified practices that might have led to contamination of patient respiratory care supplies with tap water, which might have contributed to the cluster. PMID:23973426

Peterson, Amy E; Chitnis, Amit S; Xiang, Nan; Scaletta, Joseph M; Geist, Robert; Schwartz, Jennifer; Dement, Jamie; Lawlor, Elizabeth; Lipuma, John J; O'Connell, Heather; Noble-Wang, Judith; Kallen, Alexander J; Hunt, D Charles

2013-12-01

318

42 CFR 73.9 - Responsible Official.  

Code of Federal Regulations, 2014 CFR

...neurotoxin producing species of Clostridium, Burkholderia mallei, Burkholderia pseudomallei Francisella tularensis, Ebola viruses, , Marburg virus, Variola major virus (Smallpox virus), Variola minor (Alastrim), or Yersinia pestis....

2014-10-01

319

42 CFR 73.9 - Responsible Official.  

Code of Federal Regulations, 2013 CFR

...neurotoxin producing species of Clostridium, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis, Ebola viruses, Marburg virus, Variola major virus (Smallpox virus), Variola minor (Alastrim), or Yersinia pestis....

2013-10-01

320

9 CFR 121.4 - Overlap select agents and toxins.  

Code of Federal Regulations, 2012 CFR

...HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS...Burkholderia mallei; Burkholderia pseudomallei; Hendra virus; Nipah virus; Rift Valley fever virus; Venezuelan...

2012-01-01

321

9 CFR 121.4 - Overlap select agents and toxins.  

Code of Federal Regulations, 2013 CFR

...HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS...Burkholderia mallei; *Burkholderia pseudomallei; Hendra virus; Nipah virus; Rift Valley fever virus; Venezuelan equine...

2013-01-01

322

9 CFR 121.4 - Overlap select agents and toxins.  

Code of Federal Regulations, 2011 CFR

...HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS...Burkholderia mallei; Burkholderia pseudomallei; Hendra virus; Nipah virus; Rift Valley fever virus; Venezuelan...

2011-01-01

323

9 CFR 121.4 - Overlap select agents and toxins.  

Code of Federal Regulations, 2014 CFR

...HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS...Burkholderia mallei; *Burkholderia pseudomallei; Hendra virus; Nipah virus; Rift Valley fever virus; Venezuelan equine...

2014-01-01

324

20.9% ( 3) 1. Chen K-T, Chen WJ, Malilay J, Twu S-J (2003): The public health response to the Chi-Chi  

E-print Network

;98.8.20 ( ) 1. 10 40cc 30 10 100cc 10 200cc 2. 3. 4. Burkholderia pseudomallei Leptospira interrogans Aeromonas cryptosporidiosis toxoplasmosis Hepatitis A E Influenza ( H1N1 ) Tamiflu Burkholderia pseudomallei Third

Wu, Yih-Min

325

Burkholderia cepacia Complex as Human Pathogens  

PubMed Central

Although sporadic human infection due to Burkholderia cepacia has been reported for many years, it has been only during the past few decades that species within the B. cepacia complex have emerged as significant opportunistic human pathogens. Individuals with cystic fibrosis, the most common inherited genetic disease in Caucasian populations, or chronic granulomatous disease, a primary immunodeficiency, are particularly at risk of life-threatening infection. Despite advances in our understanding of the taxonomy, microbiology, and epidemiology of B. cepacia complex, much remains unknown regarding specific human virulence factors. The broad-spectrum antimicrobial resistance demonstrated by most strains limits current therapy of infection. Recent research efforts are aimed at a better appreciation of the pathogenesis of human infection and the development of novel therapeutic and prophylactic strategies. PMID:19265997

LiPuma, John J.

2003-01-01

326

Nitrogen Fixation Genes in an Endosymbiotic Burkholderia Strain  

PubMed Central

In this paper we report the identification and characterization of a DNA region containing putative nif genes and belonging to a Burkholderia endosymbiont of the arbuscular mycorrhizal fungus Gigaspora margarita. A genomic library of total DNA extracted from the fungal spores was also representative of the bacterial genome and was used to investigate the prokaryotic genome. Screening of the library with Azospirillum brasilense nifHDK genes as the prokaryotic probes led to the identification of a 6,413-bp region. Analysis revealed three open reading frames encoding putative proteins with a very high degree of sequence similarity with the two subunits (NifD and NifK) of the component I and with component II (NifH) of nitrogenase from different diazotrophs. The three genes were arranged in an operon similar to that shown by most archaeal and bacterial diazotrophs. PCR experiments with primers designed on the Burkholderia nifHDK genes and Southern blot analysis demonstrate that they actually belong to the genome of the G. margarita endosymbiont. They offer, therefore, the first sequence for the nif operon described for Burkholderia. Reverse transcriptase PCR experiments with primers designed on the Burkholderia nifH and nifD genes and performed on total RNA extracted from spores demonstrate that the gene expression was limited to the germination phase. A phylogenetic analysis performed on the available nifK sequences placed the endosymbiotic Burkholderia close to A. brasilense. PMID:11157237

Minerdi, Daniela; Fani, Renato; Gallo, Romina; Boarino, Alessandra; Bonfante, Paola

2001-01-01

327

Invasion and Intracellular Survival of Burkholderia cepacia  

PubMed Central

Burkholderia cepacia has emerged as an important pulmonary pathogen in immunocompromised patients and in patients with cystic fibrosis (CF). Little is known about the virulence factors and pathogenesis of B. cepacia, although the persistent and sometimes invasive infections caused by B. cepacia suggest that the organism possesses mechanisms for both cellular invasion and evasion of the host immune response. In this study, cultured human cells were used to analyze the invasion and intracellular survival of B. cepacia J2315, a highly transmissible clinical isolate responsible for morbidity and mortality in CF patients. Quantitative invasion and intracellular growth assays demonstrated that B. cepacia J2315 was able to enter, survive, and replicate intracellularly in U937-derived macrophages and A549 pulmonary epithelial cells. Transmission electron microscopy of infected macrophages confirmed the presence of intracellular B. cepacia and showed that intracellular bacteria were contained within membrane-bound vacuoles. An environmental isolate of B. cepacia, strain J2540, was also examined for its ability to invade and survive intracellularly in cultured human cells. J2540 entered cultured macrophages with an invasion frequency similar to that of the clinical strain, but it was less invasive than the clinical strain in epithelial cells. In marked contrast to the clinical strain, the environmental isolate was unable to survive or replicate intracellularly in either cultured macrophages or epithelial cells. Invasion and intracellular survival may play important roles in the ability of virulent strains of B. cepacia to evade the host immune response and cause persistent infections in CF patients. PMID:10603364

Martin, Daniel W.; Mohr, Christian D.

2000-01-01

328

An outbreak of Burkholderia multivorans beyond cystic fibrosis patients.  

PubMed

Strains of the Burkholderia cepacia complex (Bcc) are opportunistic pathogens capable of causing serious infection in cystic fibrosis patients. Recently we identified a suspected outbreak of infection with Bcc strains at the University Hospital Olomouc. Seventy-four Bcc strains were isolated from 52 patients, most of whom (N = 48) did not suffer from cystic fibrosis. Most frequently (N = 46) Burkholderia multivorans was isolated and 24 (52.2%) of these strains were clonal. Fifteen of these strains were isolated from intensive care patients, five of whom died from hospital-acquired pneumonia. B. multivorans can cause serious outbreaks of infection beyond cystic fibrosis sufferers. PMID:23706672

Hanulik, V; Webber, M A; Chroma, M; Uvizl, R; Holy, O; Whitehead, R N; Baugh, S; Matouskova, I; Kolar, M

2013-07-01

329

Phylogenetic Analysis of Ara 1 and Ara 2 Burkholderia pseudomallei Isolates and Development of a Multiplex PCR Procedure for Rapid Discrimination between the Two Biotypes  

Microsoft Academic Search

morphological and biochemical profiles, except that it differs in ability to assimilate L-arabinose. These Ara 1 isolates are also less virulent than the Ara 2 isolates in animal models. In addition, clinical isolates of B. pseu- domallei available to date are almost exclusively Ara 2 . These features suggested that these two organisms may belong to distinctive species. In this

TARARAJ DHARAKUL; BOONRATN TASSANEETRITHEP; SUWANNA TRAKULSOMBOON

1999-01-01

330

Cytokine Gene Expression in Innately Susceptible BALB\\/c Mice and Relatively Resistant C57BL\\/6 Mice during Infection with Virulent Burkholderia pseudomallei  

Microsoft Academic Search

Production of cytokines including gamma interferon (IFN-g) and tumor necrosis factor alpha (TNF-a )i s an important early-stage host response following infection with intracellular pathogens. Development of immunity to these pathogens is determined to a large extent by the timing and relative level of expression of the cytokines. Numerous studies have shown that early cytokine responses involving interleukin-12 (IL-12) and

GLEN C. ULETT; NATKUNAM KETHEESAN; ROBERT G. HIRST

2000-01-01

331

Effect of colony morphology variation of Burkholderia pseudomallei on intracellular survival and resistance to antimicrobial environments in human macrophages in vitro  

E-print Network

to dissolve cell walls of bacteria. Lactoferrin is a compe- titor that works by binding iron and preventing uptake by the bacteria. Common structures for resistance to these factors such as capsule and LPS [8] were present in all isogenic morphotypes [11... single colony of type I on Ashdown agar was inoculated into 3 ml of TSB and incubated at 37°C in air in static conditions for 21 days. Bacterial culture was diluted and spread plated onto Ashdown agar. Morphotypes were identified using a morphotyping...

Tandhavanant, Sarunporn; Thanwisai, Aunchalee; Limmathurotsakul, Direk; Korbsrisate, Sunee; Day, Nicholas P J; Peacock, Sharon J; Chantratita, Narisara

2010-11-30

332

Use of Suppression-Subtractive Hybridization To Identify Genes in the Burkholderia cepacia Complex That Are Unique to Burkholderia cenocepacia  

PubMed Central

We have previously shown differences in virulence between species of the Burkholderia cepacia complex using the alfalfa infection model and the rat agar bead chronic infection model. Burkholderia cenocepacia strains were more virulent in these two infection models than Burkholderia multivorans and Burkholderia stabilis strains. In order to identify genes that may account for the increased virulence of B. cenocepacia, suppression-subtractive hybridization was performed between B. cenocepacia K56-2 and B. multivorans C5393 and between B. cenocepacia K56-2 and B. stabilis LMG14294. Genes identified included DNA modification/phage-related/insertion sequences and genes involved in cell membrane/surface structures, resistance, transport, metabolism, regulation, secretion systems, as well as genes of unknown function. Several of these genes were present in the ET12 lineage of B. cenocepacia but not in other members of the B. cepacia complex. Virulence studies in a chronic lung infection model determined that the hypothetical YfjI protein, which is unique to the ET12 clone, contributes to lung pathology. Other genes specific to B. cenocepacia and/or the ET12 lineage were shown to play a role in biofilm formation and swarming or swimming motility. PMID:16030222

Bernier, Steve P.; Sokol, Pamela A.

2005-01-01

333

Burkholderia caribensis sp. nov., an exopolysaccharide-producing bacterium isolated from vertisol microaggregates in Martinique.  

PubMed

Twenty-one exopolysaccharide-producing strains were isolated from the 5-20 microns fraction of a vertisol in the south-east of the island of Martinique in the French West Indies. Although these strains were phenotypically identified as Burkholderia cepacia or as Burkholderia glathei using BIOLOG microplates, they did not cluster genotypically by amplified rDNA restriction analysis (ARDRA) with any described Burkholderia species. A phylogenetic analysis revealed that the rrs (16S rDNA) sequences of three representative strains clustered in a single branch within the genus Burkholderia and distantly from all of the previously described species of Burkholderia for which rrs sequences were available. DNA-DNA hybridization data as well as phenotypic analyses indicated that the 21 isolates represented a single and new species for which the name Burkholderia caribensis sp. nov. is proposed (type strain MWAP64T = LMG 18531T). PMID:10319504

Achouak, W; Christen, R; Barakat, M; Martel, M H; Heulin, T

1999-04-01

334

An ancient but promiscuous host–symbiont association between Burkholderia gut symbionts and their heteropteran hosts  

PubMed Central

Here, we investigated 124 stinkbug species representing 20 families and 5 superfamilies for their Burkholderia gut symbionts, of which 39 species representing 6 families of the superfamilies Lygaeoidea and Coreoidea were Burkholderia-positive. Diagnostic PCR surveys revealed high frequencies of Burkholderia infection in natural populations of the stinkbugs, and substantial absence of vertical transmission of Burkholderia infection to their eggs. In situ hybridization confirmed localization of the Burkholderia in their midgut crypts. In the lygaeoid and coreoid stinkbugs, development of midgut crypts in their alimentary tract was coincident with the Burkholderia infection, suggesting that the specialized morphological configuration is pivotal for establishment and maintenance of the symbiotic association. The Burkholderia symbionts were easily isolated as pure culture on standard microbiological media, indicating the ability of the gut symbionts to survive outside the host insects. Molecular phylogenetic analysis showed that the gut symbionts of the lygaeoid and coreoid stinkbugs belong to a ?-proteobacterial clade together with Burkholderia isolates from soil environments and Burkholderia species that induce plant galls. On the phylogeny, the stinkbug-associated, environmental and gall-forming Burkholderia strains did not form coherent groups, indicating host–symbiont promiscuity among these stinkbugs. Symbiont culturing revealed that slightly different Burkholderia genotypes often coexist in the same insects, which is also suggestive of host–symbiont promiscuity. All these results strongly suggest an ancient but promiscuous host–symbiont relationship between the lygaeoid/coreoid stinkbugs and the Burkholderia gut symbionts. Possible mechanisms as to how the environmentally transmitted promiscuous symbiotic association has been stably maintained in the evolutionary course are discussed. PMID:20882057

Kikuchi, Yoshitomo; Hosokawa, Takahiro; Fukatsu, Takema

2011-01-01

335

Effect of agricultural management regime on Burkholderia community structure in soil.  

PubMed

The main objective of this study was to determine the Burkholderia community structure associated with areas under different agricultural management and to evaluate to which extent this community structure is affected by changes in agricultural management. Two fields with distinct soil history (arable land and permanent grassland) were exposed to three agricultural management regimes (crop rotation, maize monoculture, and grassland). By using a culture-independent approach, based on a Burkholderia-specific polymerase chain reaction-denaturing gradient gel electrophoresis system, it was possible to observe the conversion of Burkholderia communities typical for permanent grassland to those of arable land after four consecutive years. However, the time needed to achieve the reverse transition, i.e., converting the Burkholderia community associated with arable land to that of grassland, was beyond the duration of the field experiment. In addition, by applying principal response curves, the direction and extent of the conversion from grassland to arable land (maize monoculture and to crop rotation) were determined. Hence, the results suggested that agricultural practices, such as fertilization and tillage, were more effective in changing the Burkholderia community structure than agricultural management regime. To determine the effect of agricultural management on the Burkholderia population with biocontrol abilities, the culturable fraction of the Burkholderia community was assessed. The areas under permanent grassland and grassland converted to maize monoculture had the highest percentages of Burkholderia strains with antagonistic activity against Rhizoctonia solani AG-3, mainly Burkholderia pyrrocinia and Burkholderia sp. LMG 22929. The isolation frequency of antagonistic isolates from arable land was extremely low. Our results indicate that (changes in) agricultural management, mainly crop rotation, affect the frequency of isolation of antagonistic Burkholderia strains and that grassland represents a reservoir of Burkholderia species with great potential for agricultural applications. PMID:16897309

Salles, J F; van Elsas, J D; van Veen, J A

2006-08-01

336

Removal of Burkholderia cepacia biofilms with oxidants  

NASA Technical Reports Server (NTRS)

Iodine is used to disinfect the water system aboard US space shuttles and is the anticipated biocide for the international space station. Water quality on spacecraft must be maintained at the highest possible levels for the safety of the crew. Furthermore, the treatment process used to maintain the quality of water on research must be robust and operate for long periods with minimal crew intervention. Biofilms are recalcitrant and pose a major threat with regard to chronic contamination of spacecraft water systems. We measured the effectiveness of oxidizing biocides on the removal and regrowth of Burkholderia (Pseudomonas) cepacia biofilms. B. cepacia, isolated from the water distribution system of the space shuttle Discovery, was grown in continuous culture to produce a bacterial contamination source for biofilm formation and removal studies. A 10(7) CFU ml-1 B. cepacia suspension, in distilled water, was used to form biofilms on 3000 micrometers2 glass surfaces. Rates of attachment were measured directly with image analysis and were found to be 7.8, 15.2, and 22.8 attachment events h-1 for flow rates of 20.7, 15.2, and 9.8 ml min-1, respectively. After 18 h of formation, the B. cepacia biofilms were challenged with oxidants (ozone, chlorine, and iodine) and the rates of biofilm removal determined by image analysis. Fifty percent of the biofilm material was removed in the first hour of continous treatment with 24 mg l-1 chlorine or 2 mg l-1 ozone. Iodine (48 mg l-1) did not remove any measurable cellular material after 6 h continuous contact. After this first removal of biofilms by the oxidants, the surface was allowed to refoul and was again treated with the biocide. Iodine was the only compound that was unable to remove cellular debris from either primary or secondary biofilms. Moreover, treating primary biofilms with iodine increased the rate of formation of secondary biofilms, from 4.4 to 5.8 attachment events h-1. All the oxidants tested inactivated the B. cepacia associated with both primary and secondary biofilms. The amount of biocide needed to inactivate 50% of planktonic B. cepacia in 10 min at 25 degrees C was 8.4, 0.5, and 0.2 mg l-1 for iodine, chlorine, and ozone, respectively. The data suggest that iodine maynot be the best chemical for treating of biofilms when removal of cellular material is required.

Koenig, D. W.; Mishra, S. K.; Pierson, D. L.

1995-01-01

337

The role of cystic fibrosis conductance regulator in the clearance of Burkholderia cenocepacia by macrophages.  

E-print Network

??Burkholderia cenocepacia is an opportunistic Gram-negative bacterium that causes chronic respiratory infection in cystic fibrosis (CF) patients, leading to rapid decline of lung function. CF… (more)

Ostapska, Hanna

2012-01-01

338

Passive protection of diabetic rats with antisera specific for the polysaccharide portion of the lipopolysaccharide isolated from Pseudomonas pseudomallei  

PubMed Central

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-positive species, were recognized, although cross-reaction occurred using the anticonjugate serum with some strains of Pseudomonas cepacia serotype A, a closely related bacterium. Passive protection studies using a diabetic rat model of P pseudomallei infection showed that partially purified rabbit polyclonal and mouse monoclonal antisera were protective when the median lethal dose was raised by four to five orders of magnitude. The wide distribution of the polysaccharide antigen among isolates of P pseudomallei used in this study and the protective role of antibody to the conjugated polysaccharide antigen suggest potential as a vaccine. PMID:22346496

Bryan, Larry E; Wong, Sallene; Woods, Don E; Dance, David AB; Chaowagul, W

1994-01-01

339

Draft Genome Sequence of the Lignin-Degrading Burkholderia sp. Strain LIG30, Isolated from Wet Tropical Forest Soil  

PubMed Central

Burkholderia species are common soil Betaproteobacteria capable of degrading recalcitrant aromatic compounds and xenobiotics. Burkholderia sp. strain LIG30 was isolated from wet tropical forest soil and is capable of utilizing lignin as a sole carbon source. Here we report the draft genome sequence of Burkholderia sp. strain LIG30. PMID:24948777

Woo, Hannah L.; Utturkar, Sagar; Klingeman, Dawn; Simmons, Blake A.; DeAngelis, Kristen M.; Brown, Steven D.

2014-01-01

340

Draft Genome Sequence of the Lignin-Degrading Burkholderia sp. Strain LIG30, Isolated from Wet Tropical Forest Soil.  

PubMed

Burkholderia species are common soil Betaproteobacteria capable of degrading recalcitrant aromatic compounds and xenobiotics. Burkholderia sp. strain LIG30 was isolated from wet tropical forest soil and is capable of utilizing lignin as a sole carbon source. Here we report the draft genome sequence of Burkholderia sp. strain LIG30. PMID:24948777

Woo, Hannah L; Utturkar, Sagar; Klingeman, Dawn; Simmons, Blake A; DeAngelis, Kristen M; Brown, Steven D; Hazen, Terry C

2014-01-01

341

Draft Genome Sequence of the Organophosphorus Compound-Degrading Burkholderia zhejiangensis Strain CEIB S4-3.  

PubMed

Burkholderia species are widely distributed in the environment. A Burkholderia zhejiangensis strain was isolated from pesticide-contaminated soil from an agricultural field in Mexico and identified as an organophosphorus compound-degrading bacterium. In this study, we report the draft genome sequence of Burkholderia zhejiangensis strain CEIB S4-3. PMID:25523778

Hernández-Mendoza, Armando; Martínez-Ocampo, Fernando; Lozano-Aguirre Beltrán, Luis Fernando; Popoca-Ursino, Elida Carolina; Ortiz-Hernández, Laura; Sánchez-Salinas, Enrique; Dantán-González, Edgar

2014-01-01

342

Draft Genome Sequence of the Organophosphorus Compound-Degrading Burkholderia zhejiangensis Strain CEIB S4-3  

PubMed Central

Burkholderia species are widely distributed in the environment. A Burkholderia zhejiangensis strain was isolated from pesticide-contaminated soil from an agricultural field in Mexico and identified as an organophosphorus compound-degrading bacterium. In this study, we report the draft genome sequence of Burkholderia zhejiangensis strain CEIB S4-3. PMID:25523778

Hernández-Mendoza, Armando; Martínez-Ocampo, Fernando; Lozano-Aguirre Beltrán, Luis Fernando; Popoca-Ursino, Elida Carolina; Ortiz-Hernández, Laura; Sánchez-Salinas, Enrique

2014-01-01

343

Nodulation of Cyclopia spp. (Leguminosae, Papilionoideae) by Burkholderia tuberum  

PubMed Central

Background and Aims Species of the genus Burkholderia, from the Betaproteobacteria, have been isolated from legume nodules, but so far they have only been shown to form symbioses with species of Mimosa, sub-family Mimosoideae. This work investigates whether Burkholderia tuberum strains STM678 (isolated from Aspalathus carnosa) and DUS833 (from Aspalathus callosa) can nodulate species of the South African endemic papilionoid genera Cyclopia (tribe Podalyrieae) and Aspalathus (Crotalarieae) as well as the promiscuous legume Macroptilium atropurpureum (Phaseoleae). Method Bacterial strains and the phylogeny of their symbiosis-related (nod) genes were examined via 16S rRNA gene sequencing. Seedlings were grown in liquid culture and inoculated with one of the two strains of B. tuberum or with Sinorhizobium strain NGR 234 (from Lablab purpureus), Mesorhizobium strain DUS835 (from Aspalathus linearis) or Methylobacterium nodulans (from Crotalaria podocarpa). Some nodules, inoculated with green fluorescence protein (GFP)-tagged strains, were examined by light and electron microscopy coupled with immunogold labelling with a Burkholderia-specific antibody. The presence of active nitrogenase was checked by immunolabelling of nitrogenase and by the acetylene reduction assay. B. tuberum STM678 was also tested on a wide range of legumes from all three sub-families. Key Results Nodules were not formed on any of the Aspalathus spp. Only B. tuberum nodulated Cyclopia falcata, C. galioides, C. genistoides, C. intermedia and C. pubescens. It also effectively nodulated M. atropurpureum but no other species tested. GFP-expressing inoculant strains were located inside infected cells of C. genistoides, and bacteroids in both Cyclopia spp. and M. atropurpureum were immunogold-labelled with antibodies against Burkholderia and nitrogenase. Nitrogenase activity was also shown using the acetylene reduction assay. This is the first demonstration that a ?-rhizobial strain can effectively nodulate papilioinoid legumes. Conclusions Papilionoid legumes from widely different tribes can be nodulated by ?-rhizobia, forming both indeterminate (Cyclopia) and determinate (Macroptilium) nodules. PMID:17881339

Elliott, Geoffrey N.; Chen, Wen-Ming; Bontemps, Cyril; Chou, Jui-Hsing; Young, J. Peter W.; Sprent, Janet I.; James, Euan K.

2007-01-01

344

Genomic Analysis of Burkholderia And Rhodococcus equi Bacteriophages  

E-print Network

is Mycobacterium tuberculosis, the etiological agent of tuberculosis. M. tuberculosis is phagocytized by alveolar macrophages and is 3 capable of surviving in the macrophage and will eventually cause cell lysis. R. equi manifests a similar molecular... GENOMIC ANALYSIS OF Burkholderia AND Rhodococcus equi BACTERIOPHAGES Major: Microbiology April 2008 Submitted to the Office of Undergraduate Research Texas A&M University in partial fulfillment of the requirements...

Orchard II, Robert C.

2011-08-04

345

Iron acquisition mechanisms of the Burkholderia cepacia complex  

Microsoft Academic Search

The Burkholderia cepacia complex (Bcc) is comprised of at least 10 closely related species of Gram-negative proteobacteria that are associated with\\u000a infections in certain groups of immunocompromised individuals, particularly those with cystic fibrosis. Infections in humans\\u000a tend to occur in the lungs, which present an iron-restricted environment to a prospective pathogen, and accordingly members\\u000a of the Bcc appear to possess

Mark S. Thomas

2007-01-01

346

Identification and enzymatic characterization of acid phosphatase from Burkholderia gladioli  

PubMed Central

Background The genus Burkholderia is widespread in diverse ecological niches, the majority of known species are soil bacteria that exhibit different types of non-pathogenic interactions with plants. Burkholderia species are versatile organisms that solubilize insoluble minerals through the production of organic acids, which increase the availability of nutrients for the plant. Therefore these bacteria are promising candidates for biotechnological applications. Results Burkholderia sp. (R 3.25 isolate) was isolated from agricultural soil in Ponta Grossa-PR-Brazil and identified through analysis of the 16S rDNA as a strain classified as Burkholderia gladioli. The expression of membrane-bound acid phosphatase (MBAcP) was strictly regulated with optimal expression at a concentration of phosphorus 5 mM. The apparent optimum pH for the hydrolysis of p-nitrophenylphosphate (PNPP) was 6.0. The hydrolysis of PNPP by the enzyme exhibited a hyperbolic relationship with increasing concentration of substrate and no inhibition by excess of substrate was observed. Kinetic data revealed that the hydrolysis of PNPP exhibited cooperative kinetics with n?=?1.3, Vm?=?113.5 U/mg and K0.5?=?65 ?M. The PNPPase activity was inhibited by vanadate, p-hydroxymercuribenzoate, arsenate and phosphate, however the activity was not inhibited by calcium, levamisole, sodium tartrate, EDTA, zinc, magnesium, cobalt, ouabain, oligomycin or pantoprazol. Conclusion The synthesis of membrane-bound non-specific acid phosphatase, strictly regulated by phosphate, and its properties suggest that this bacterium has a potential biotechnological application to solubilize phosphate in soils with low levels of this element, for specific crops. PMID:24713147

2014-01-01

347

Burkholderia eburnea sp. nov., isolated from peat soil.  

PubMed

A novel aerobic bacterium, designated strain RR11(T), was isolated from peat soil and was characterized by using a polyphasic taxonomic approach and identified in order to determine its taxonomic position. Strain RR11(T) is a Gram-negative, non-sporulating, motile, short-rod-shaped bacterium. 16S rRNA gene sequence analysis identified this strain as a member of the genus Burkholderia of the class Betaproteobacteria. The highest degrees of gene sequence similarity were found with Burkholderia tropica Ppe8(T) (98.0?%), B. bannensis E25(T) (97.3?%), B. ferrariae FeGI01(T) (97.1?%), B. unamae MTI-641(T) (97.1?%) and B. heleia SA41(T) (97.1?%). Strain RR11(T) had the following chemotaxonomic characteristics: the major ubiquinone was Q-8, the DNA G+C content was 60.8 mol%, the major fatty acids were C16?:?0, C19?:?0 cyclo ?8c and C17?:?0 cyclo and the polar lipid profile contained phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and an unknown aminophospholipid. Based on its morphological, physiological and chemotaxonomic characteristics, together with 16S rRNA gene sequence comparison results, strain RR11(T) represents a novel species, for which the name Burkholderia eburnea sp. nov. is proposed. The type strain is strain RR11(T) (?=?KEMC 7302-065(T)?=?JCM 18070(T)). PMID:24363296

Kang, Sang Rim; Srinivasan, Sathiyaraj; Lee, Sang Seob

2014-04-01

348

Burkholderia pseudomultivorans sp. nov., a novel Burkholderia cepacia complex species from human respiratory samples and the rhizosphere.  

PubMed

Eleven Burkholderia cepacia-like isolates of human clinical and environmental origin were examined by a polyphasic approach including recA and 16S rRNA sequence analysis, multilocus sequence analysis (MLSA), DNA base content determination, fatty acid methyl ester analysis, and biochemical characterization. The results of this study demonstrate that these isolates represent a novel species within the B. cepacia complex (Bcc) for which we propose the name Burkholderia pseudomultivorans. The type strain is strain LMG 26883(T) (=CCUG 62895(T)). B. pseudomultivorans can be differentiated from other Bcc species by recA gene sequence analysis, MLSA, and several biochemical tests including growth at 42°C, acidification of sucrose and adonitol, lysine decarboxylase and ?-galactosidase activity, and esculin hydrolysis. PMID:23867250

Peeters, Charlotte; Zlosnik, James E A; Spilker, Theodore; Hird, Trevor J; LiPuma, John J; Vandamme, Peter

2013-10-01

349

Draft Genome Sequence of Burkholderia dolosa PC543 Isolated from Cystic Fibrosis Airways.  

PubMed

Burkholderia dolosa is a member of the Burkholderia cepacia complex, a group of opportunistic bacterial pathogens often associated with fatal chronic infections in the lungs of patients suffering from cystic fibrosis (CF). Here, we announce the draft genome sequence of B. dolosa PC543 (LMG 19468), a CF airway isolate. PMID:24526633

Workentine, Matthew L; Surette, Michael G; Bernier, Steve P

2014-01-01

350

Genome characterization of a novel Burkholderia cepacia complex genomovar isolated from dieback affected mango orchards.  

PubMed

We characterized the genome of the antibiotic resistant, caseinolytic and non-hemolytic Burkholderia sp. strain TJI49, isolated from mango trees (Mangifera indica L.) with dieback disease. This isolate produced severe disease symptoms on the indicator plants. Next generation DNA sequencing and short-read assembly generated the 60X deep 7,631,934 nucleotide draft genome of Burkholderia sp. TJI49 which comprised three chromosomes and at least one mega plasmid. Genome annotation studies revealed a total 8,992 genes, out of which 8,940 were protein coding genes. Comparative genomics and phylogenetics identified Burkholderia sp. TJI49 as a distinct species of Burkholderia cepacia complex (BCC), closely related to B. multivorans ATCC17616. Genome-wide sequence alignment of this isolate with replicons of BCC members showed conservation of core function genes but considerable variations in accessory genes. Subsystem-based gene annotation identified the active presence of wide spread colonization island and type VI secretion system in Burkholderia sp. TJI49. Sequence comparisons revealed (a) 28 novel ORFs that have no database matches and (b) 23 ORFs with orthologues in species other than Burkholderia, indicating horizontal gene transfer events. Fold recognition of novel ORFs identified genes encoding pertactin autotransporter-like proteins (a constituent of type V secretion system) and Hap adhesion-like proteins (involved in cell-cell adhesion) in the genome of Burkholderia sp. TJI49. The genomic characterization of this isolate provided additional information related to the 'pan-genome' of Burkholderia species. PMID:23653265

Khan, Asifullah; Asif, Huma; Studholme, David J; Khan, Ishtiaq A; Azim, M Kamran

2013-11-01

351

The Driskill Graduate Program Northwestern University  

E-print Network

by Burkholderia pseudomallei Jeffery F. Miller, Ph.D. is the M. Philip Davis Chair in Microbiology and Immunology cycles of Bordetella pertussis, which causes whooping cough, and Burkholderia pseudomallei, which causes and Burkholderia, iv) biofilm formation and the hyper-colonization phenotype of Staphylococcus epidermiditis, and v

Engman, David M.

352

The genetic basis of cadmium resistance of Burkholderia cenocepacia.  

PubMed

Burkholderia species are highly resistant to heavy metals (HMs), yet their resistance mechanisms are largely unknown. In this study we screened 5000 mini-Tn5 transposon insertion mutants of Burkholderia cenocepacia H111 for loss of cadmium tolerance. Of the four genes identified three affected outer membrane biogenesis and integrity or DNA repair. The fourth gene, BCAE0587, encoded a P1-type ATPase belonging to the CadA family of HM exporters. CadA-deficient strains lost the ability to grow in the presence of cadmium, zinc and lead, whereas resistance to nickel, copper and cobalt was not affected. Expression studies using a transcriptional fusion of the cadA promoter to gfp confirmed this specificity, as induction was only observed in presence of cadmium, zinc and lead. The promoter activity was found to be highest at neutral pH with an activation threshold of 30?nM cadmium. Inoculation of the HM-hyperaccumulating plant Arabidopsis halleri with a RFP-marked derivative of B.?cenocepacia H111 containing the PcadA -gfp fusion demonstrated the applicability of this biosensor for monitoring cadmium at the single cell level in a natural environment. PMID:23760902

Schwager, Stephan; Lumjiaktase, Putthapoom; Stöckli, Martina; Weisskopf, Laure; Eberl, Leo

2012-10-01

353

Microbial degradation of quinoline by immobilized cells of Burkholderia pickettii.  

PubMed

A quinoline-biodegrading microorganism was isolated from activated sludge of coke-oven wastewater treatment plant using quinoline as sole carbon and nitrogen source. It is a gram negative, rod-shaped and aerobic strain, which was identified as Burkholderia pickettii. The biodegradation of quinoline was carried out with this isolated strain. Analysis by high performance liquid chromatography and gas chromatography/mass spectrum (GC/MS) revealed that 2-hydroxyquinoline (2-OH-Q) was the first intermediate in the course of quinoline biodegradation. A novel immobilization carrier, that is, polyvinyl alcohol (PVA)-gauze hybrid carrier, was developed. The isolated strain was immobilized by two different immobilizing techniques and used for the quinolinerdegradation. It was found that biodegradation rate of quinoline by the microorganisms immobilized on PVA-gauze hybrid carrier was faster than that by the microorganisms immobilized in PVA gel beads. Kinetics of quinoline biodegradation by cells of Burkholderia pickettii immobilized on PVA-gauze hybrid carrier was investigated. The results demonstrate that quinoline degradation could be described by zero-order reaction rate equation when the initial quinoline concentration was in the range of 50-500 mg l(-1). PMID:12108721

Jianlong, Wang; Xiangchun, Quan; Liping, Han; Yi, Qian; Hegemann, Werner

2002-05-01

354

SOFTWARE Open Access Mining locus tags in PubMed Central to improve  

E-print Network

in supplementary tables and publications outside the OA subset in Burkholderia pseudomallei K96243 for comparison materials and 9% from publications outside the OA subset. Conclusions: B. pseudomallei locus tags within

Kaski, Samuel

355

Conservation of a novel protein associated with an antibiotic efflux operon in Burkholderia cenocepacia  

E-print Network

; Antibiotic efflux; Hydrolytic enzymes 1. Introduction Burkholderia cepacia complex strains are important modeling suggests that LlpE is a member of the a/b hydrolase enzyme family. Identification of strong

Chattopadhyay, Sujay

356

Burkholderia spp. Infections in Cystic Fibrosis Patients in British Columbia, Canada: 30 Years' Experience.  

PubMed

Rationale: We have been collecting Burkholderia species bacteria from cystic fibrosis (CF) patients for the last 30 years, during which time the understanding of their multispecies taxonomy and infection control has evolved substantially. Objectives: To evaluate the long-term (30 year) epidemiology and clinical outcome of Burkholderia infection in CF, and fully define the risks associated with each species. Methods: Isolates from Burkholderia positive patients (n=107) were speciated and typed annually for each infected patient. Microbiological and clinical data were evaluated by thorough review of patient's charts, and statistical analyses performed to define significant epidemiological factors. Measurements and Main Results: Prior to 1995 the majority of new Burkholderia infections were caused by epidemic clones of B. cenocepacia; after implementation of new infection control measures in 1995, B. multivorans became the most prevalent species.. Survival analysis showed that CF patients infected with B. cenocepacia had a significantly worse outcome than those with B. multivorans, and a novel finding was that following Burkholderia infection, the prognosis for females was significantly worse than for males. Conclusions: B. multivorans and B. cenocepacia have been the predominant Burkholderia species infecting people with CF in Vancouver. The implementation of infection control measures were successful in preventing new acquisition of epidemic strains of B. cenocepacia leaving non-clonal B. multivorans as the most prevalent species. Historically, survival following infection with B. cenocepacia has been significantly worse than B. multivorans infection, and of major new significance we show that this poor clinical outcome was gender biased towards females. PMID:25474359

Zlosnik, James E A; Zhou, Guohai; Brant, Rollin; Henry, Deborah A; Hird, Trevor J; Mahenthiralingam, Eshwar; Chilvers, Mark A; Wilcox, Pearce; Speert, David P

2014-12-01

357

A Structural Biology Approach Enables the Development of Antimicrobials Targeting Bacterial Immunophilins  

PubMed Central

Macrophage infectivity potentiators (Mips) are immunophilin proteins and essential virulence factors for a range of pathogenic organisms. We applied a structural biology approach to characterize a Mip from Burkholderia pseudomallei (BpML1), the causative agent of melioidosis. Crystal structure and nuclear magnetic resonance analyses of BpML1 in complex with known macrocyclics and other derivatives led to the identification of a key chemical scaffold. This scaffold possesses inhibitory potency for BpML1 without the immunosuppressive components of related macrocyclic agents. Biophysical characterization of a compound series with this scaffold allowed binding site specificity in solution and potency determinations for rank ordering the set. The best compounds in this series possessed a low-micromolar affinity for BpML1, bound at the site of enzymatic activity, and inhibited a panel of homologous Mip proteins from other pathogenic bacteria, without demonstrating toxicity in human macrophages. Importantly, the in vitro activity of BpML1 was reduced by these compounds, leading to decreased macrophage infectivity and intracellular growth of Burkholderia pseudomallei. These compounds offer the potential for activity against a new class of antimicrobial targets and present the utility of a structure-based approach for novel antimicrobial drug discovery. PMID:24366729

Fox, David; Jenner, Dominic; Juli, Christina; Pierce, Phillip G.; Abendroth, Jan; Muruthi, Muigai; Safford, Kris; Anderson, Vanessa; Atkins, Kateri; Barnes, Steve R.; Moen, Spencer O.; Raymond, Amy C.; Stacy, Robin; Myler, Peter J.; Staker, Bart L.; Harmer, Nicholas J.; Norville, Isobel H.; Holzgrabe, Ulrike; Sarkar-Tyson, Mitali; Edwards, Thomas E.; Lorimer, Donald D.

2014-01-01

358

A case of melioidosis probably acquired by inhalation of dusts during a helicopter flight in a healthy traveler returning from singapore.  

PubMed

We present a case of melioidosis in an Italian male returning from Singapore after a short travel. He probably acquired the disease by inhalation, which is not the typical mode of transmission, in the absence of evident risk factors. The diagnosis was confirmed by real-time polymerase chain reaction of the culture while serology was useful to assess professional exposure among laboratory workers. Treatment consisted of an initial intensive phase with meropenem and trimethoprim-sulfamethaxazole (TMP-SMX), followed by 6?months of eradication therapy with TMP-SMX. PMID:25183194

Amadasi, Silvia; Dal Zoppo, Sarah; Bonomini, Annalisa; Bussi, Anna; Pedroni, Palmino; Balestrieri, Gianpaolo; Signorini, Liana; Castelli, Francesco

2015-01-01

359

Variable Ammonia Production Among Smooth and Rough Strains of Pseudomonas pseudomallei: Resemblance to Bacteriocin Production  

PubMed Central

The colonial morphology of some strains of Pseudomonas pseudomallei was correlated with certain biochemical and physiological traits. After 3 days of growth on Wahba or heart infusion agars, smooth-colony strains generated toxic amounts of ammonia. Under the same conditions, the rough strains simultaneously produced oxalic acid which decreased the inhibitory concentration of ammonia. The ammonia-ammonium concentrations in smooth cultures exhibited certain bacteriocin-like characteristics. An unusually stable, smooth strain (strain 165) was chosen to compare and emphasize any differences with typical, rough strain 7815. Three-day-old smooth cultures grown on Wahba agar containing 3% (w/v) glycerol demonstrated ammonia toxicity. The substitution of glucose for glycerol completely obviated this toxicity. In highly aerated Wahba broth containing glucose, the amount of ammonia found in strain 165 smooth cultures and the amount of oxalic acid found in strain 7815 rough cultures were greatly reduced. In Difco nitrate broth smooth strain 165 did not form gas, and it reduced nitrate to nitrite only. Strain 7815 produced a gas and reduced both nitrate and nitrite. PMID:4562401

Rogul, Marvin; Carr, Susan R.

1972-01-01

360

Pathogens penetrating the central nervous system: infection pathways and the cellular and molecular mechanisms of invasion.  

PubMed

The brain is well protected against microbial invasion by cellular barriers, such as the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB). In addition, cells within the central nervous system (CNS) are capable of producing an immune response against invading pathogens. Nonetheless, a range of pathogenic microbes make their way to the CNS, and the resulting infections can cause significant morbidity and mortality. Bacteria, amoebae, fungi, and viruses are capable of CNS invasion, with the latter using axonal transport as a common route of infection. In this review, we compare the mechanisms by which bacterial pathogens reach the CNS and infect the brain. In particular, we focus on recent data regarding mechanisms of bacterial translocation from the nasal mucosa to the brain, which represents a little explored pathway of bacterial invasion but has been proposed as being particularly important in explaining how infection with Burkholderia pseudomallei can result in melioidosis encephalomyelitis. PMID:25278572

Dando, Samantha J; Mackay-Sim, Alan; Norton, Robert; Currie, Bart J; St John, James A; Ekberg, Jenny A K; Batzloff, Michael; Ulett, Glen C; Beacham, Ifor R

2014-10-01

361

Aerosol Phage Therapy Efficacy in Burkholderia cepacia Complex Respiratory Infections  

PubMed Central

Phage therapy has been suggested as a potential treatment for highly antibiotic-resistant bacteria, such as the species of the Burkholderia cepacia complex (BCC). To address this hypothesis, experimental B. cenocepacia respiratory infections were established in mice using a nebulizer and a nose-only inhalation device. Following infection, the mice were treated with one of five B. cenocepacia-specific phages delivered as either an aerosol or intraperitoneal injection. The bacterial and phage titers within the lungs were assayed 2 days after treatment, and mice that received the aerosolized phage therapy demonstrated significant decreases in bacterial loads. Differences in phage activity were observed in vivo. Mice that received phage treatment by intraperitoneal injection did not demonstrate significantly reduced bacterial loads, although phage particles were isolated from their lung tissue. Based on these data, aerosol phage therapy appears to be an effective method for treating highly antibiotic-resistant bacterial respiratory infections, including those caused by BCC bacteria. PMID:24798268

Semler, Diana D.; Goudie, Amanda D.; Finlay, Warren H.

2014-01-01

362

Aerosol phage therapy efficacy in Burkholderia cepacia complex respiratory infections.  

PubMed

Phage therapy has been suggested as a potential treatment for highly antibiotic-resistant bacteria, such as the species of the Burkholderia cepacia complex (BCC). To address this hypothesis, experimental B. cenocepacia respiratory infections were established in mice using a nebulizer and a nose-only inhalation device. Following infection, the mice were treated with one of five B. cenocepacia-specific phages delivered as either an aerosol or intraperitoneal injection. The bacterial and phage titers within the lungs were assayed 2 days after treatment, and mice that received the aerosolized phage therapy demonstrated significant decreases in bacterial loads. Differences in phage activity were observed in vivo. Mice that received phage treatment by intraperitoneal injection did not demonstrate significantly reduced bacterial loads, although phage particles were isolated from their lung tissue. Based on these data, aerosol phage therapy appears to be an effective method for treating highly antibiotic-resistant bacterial respiratory infections, including those caused by BCC bacteria. PMID:24798268

Semler, Diana D; Goudie, Amanda D; Finlay, Warren H; Dennis, Jonathan J

2014-07-01

363

Cross infection between cystic fibrosis patients colonised with Burkholderia cepacia  

PubMed Central

Whilst patient to patient spread of the respiratory pathogen Burkholderia cepacia is well recognised between patients with cystic fibrosis, prompting a strict segregation policy, cross colonisation between cystic fibrosis patients already infected with B cepacia has not been described and surveys show a very low incidence of patients with more than one strain. Five adult cystic fibrosis patients with B cepacia are presented who became cross colonised with a second B cepacia (UK epidemic) strain, four of whom then died, three from the cepacia syndrome. These cases show that, amongst segregated patients, cross colonisation with different B cepacia strains is possible, and even in these patients the acquisition of the UK epidemic strain may have a fatal outcome. In future it may be necessary to segregate cystic fibrosis patients colonised with the UK epidemic strain from all other patients with cystic fibrosis.?? PMID:9708241

Ledson, M; Gallagher, M; Corkill, J; Hart, C; Walshaw, M

1998-01-01

364

Production of bioactive volatiles by different Burkholderia ambifaria strains.  

PubMed

Increasing evidence indicates that volatile compounds emitted by bacteria can influence the growth of other organisms. In this study, the volatiles produced by three different strains of Burkholderia ambifaria were analysed and their effects on the growth of plants and fungi, as well as on the antibiotic resistance of target bacteria, were assessed. Burkholderia ambifaria emitted highly bioactive volatiles independently of the strain origin (clinical environment, rhizosphere of pea, roots of maize). These volatile blends induced significant biomass increase in the model plant Arabidopsis thaliana as well as growth inhibition of two phytopathogenic fungi (Rhizoctonia solani and Alternaria alternata). In Escherichia coli exposed to the volatiles of B. ambifaria, resistance to the aminoglycoside antibiotics gentamicin and kanamycin was found to be increased. The volatile blends of the three strains were similar, and dimethyl disulfide was the most abundant compound. Sulfur compounds, ketones, and aromatic compounds were major groups in all three volatile profiles. When applied as pure substance, dimethyl disulfide led to increased plant biomass, as did acetophenone and 3-hexanone. Significant fungal growth reduction was observed with high concentrations of dimethyl di- and trisulfide, 4-octanone, S-methyl methanethiosulphonate, 1-phenylpropan-1-one, and 2-undecanone, while dimethyl trisulfide, 1-methylthio-3-pentanone, and o-aminoacetophenone increased resistance of E. coli to aminoglycosides. Comparison of the volatile profile produced by an engineered mutant impaired in quorum-sensing (QS) signalling with the corresponding wild-type led to the conclusion that QS is not involved in the regulation of volatile production in B. ambifaria LMG strain 19182. PMID:23832658

Groenhagen, Ulrike; Baumgartner, Rita; Bailly, Aurélien; Gardiner, Amber; Eberl, Leo; Schulz, Stefan; Weisskopf, Laure

2013-07-01

365

40 CFR 180.1325 - Heat-killed Burkholderia spp. strain A396 cells and spent fermentation media exemption from the...  

Code of Federal Regulations, 2014 CFR

...Heat-killed Burkholderia spp. strain A396 cells and spent fermentation media exemption...Heat-killed Burkholderia spp. strain A396 cells and spent fermentation media exemption...heat-killed Burkholderia spp. strain A396 cells and spent fermentation media in or...

2014-07-01

366

Diversity of the parB and repA genes of the Burkholderia cepacia complex and their utility for rapid identification of Burkholderia cenocepacia  

Microsoft Academic Search

BACKGROUND: Burkholderia cenocepacia is the most prominent species of the B. cepacia complex (Bcc), a group of nine closely related and difficult to identify bacteria that cause serious infections in patients with cystic fibrosis. Despite its clinical relevance, identification of B. cenocepacia as a single species is unavailable, as it splits by a widely used recA gene-based PCR identification method

Pavel Drevinek; Adam Baldwin; Christopher G Dowson; Eshwar Mahenthiralingam

2008-01-01

367

Oxalotrophy, a widespread trait of plant-associated Burkholderia species, is involved in successful root colonization of lupin and maize by Burkholderia phytofirmans  

PubMed Central

Plant roots and shoots harbor complex bacterial communities. Early seed and plantlet colonization plays a key role in determining which bacterial populations will successfully invade plant tissues, yet the mechanisms enabling plants to select for beneficial rather than harmful populations are largely unknown. In this study, we demonstrate a role of oxalate as a determinant in this selection process, using members of the genus Burkholderia as model organisms. Oxalotrophy, i.e., the ability to use oxalate as a carbon source, was found to be a property strictly associated with plant-beneficial species of the Burkholderia genus, while plant pathogenic (B. glumae, B. plantarii) or human opportunistic pathogens (Burkholderia cepacia complex strains) were unable to degrade oxalate. We further show that oxalotrophy is required for successful plant colonization by the broad host endophyte Burkholderia phytofirmans PsJN: an engineered ?oxc mutant, which lost the ability to grow on oxalate, was significantly impaired in early colonization of both lupin and maize compared with the wild-type. This work suggests that in addition to the role of oxalate in heavy metal tolerance of plants and in virulence of phytopathogenic fungi, it is also involved in specifically recruiting plant-beneficial members from complex bacterial communities. PMID:24409174

Kost, Thomas; Stopnisek, Nejc; Agnoli, Kirsty; Eberl, Leo

2014-01-01

368

Oxalotrophy, a widespread trait of plant-associated Burkholderia species, is involved in successful root colonization of lupin and maize by Burkholderia phytofirmans.  

PubMed

Plant roots and shoots harbor complex bacterial communities. Early seed and plantlet colonization plays a key role in determining which bacterial populations will successfully invade plant tissues, yet the mechanisms enabling plants to select for beneficial rather than harmful populations are largely unknown. In this study, we demonstrate a role of oxalate as a determinant in this selection process, using members of the genus Burkholderia as model organisms. Oxalotrophy, i.e., the ability to use oxalate as a carbon source, was found to be a property strictly associated with plant-beneficial species of the Burkholderia genus, while plant pathogenic (B. glumae, B. plantarii) or human opportunistic pathogens (Burkholderia cepacia complex strains) were unable to degrade oxalate. We further show that oxalotrophy is required for successful plant colonization by the broad host endophyte Burkholderia phytofirmans PsJN: an engineered ?oxc mutant, which lost the ability to grow on oxalate, was significantly impaired in early colonization of both lupin and maize compared with the wild-type. This work suggests that in addition to the role of oxalate in heavy metal tolerance of plants and in virulence of phytopathogenic fungi, it is also involved in specifically recruiting plant-beneficial members from complex bacterial communities. PMID:24409174

Kost, Thomas; Stopnisek, Nejc; Agnoli, Kirsty; Eberl, Leo; Weisskopf, Laure

2014-01-01

369

Draft Genome Sequence of Burkholderia pyrrocinia Lyc2, a Biological Control Strain That Can Suppress Multiple Plant Microbial Pathogens  

PubMed Central

Burkholderia pyrrocinia strain Lyc2 was isolated from the tobacco rhizosphere in China. This bacterium exhibits a remarkable capacity to inhibit the growth of multiple pathogens and shows strong suppression of cotton seedling damping-off. Here, we present the draft genome sequence of Burkholderia pyrrocinia strain Lyc2. PMID:25278535

Wang, Xiao-Qiang; Showmaker, Kurt C.; Yu, Xiao-Qing; Bi, Tao; Hsu, Chuan-Yu; Baird, Sonya M.; Peterson, Daniel G.

2014-01-01

370

Whole-Genome Sequence of Burkholderia sp. Strain RPE67, a Bacterial Gut Symbiont of the Bean Bug Riptortus pedestris  

PubMed Central

Burkholderia sp. strain RPE67 is a bacterial symbiont isolated from a field-collected bean bug, Riptortus pedestris. To understand the genetic basis of the insect-microbe symbiosis, we performed whole-genome sequencing of the Burkholderia strain, revealing an 8.69-Mb genome consisting of three chromosomes and three plasmids. PMID:24948758

Takeshita, Kazutaka; Shibata, Tomoko F.; Nikoh, Naruo; Nishiyama, Tomoaki; Hasebe, Mitsuyasu; Fukatsu, Takema; Shigenobu, Shuji

2014-01-01

371

Burkholderia jiangsuensis sp. nov., a methyl parathion degrading bacterium, isolated from methyl parathion contaminated soil.  

PubMed

A methyl parathion (MP) degrading bacterial strain, designated MP-1(T), was isolated from a waste land where pesticides were formerly manufactured in Jiangsu province, China. Polyphasic taxonomic studies showed that MP-1(T) is a Gram-stain-negative, non-spore-forming, rod-shaped and motile bacterium. The bacterium could grow at salinities of 0-1?% (w/v) and temperatures of 15-40 °C. Strain MP-1(T) could reduce nitrate to nitrite, utilize d-glucose and l-arabinose, but not produce indole, or hydrolyse gelatin. Phylogenetic analysis based on 16S rRNA gene sequences demonstrated that MP-1(T) belongs to the genus Burkholderia, showing highest sequence similarity to Burkholderia grimmiae DSM 25160(T) (98.5?%), and similar strains including Burkholderia zhejiangensis OP-1(T) (98.2?%), Burkholderia choica LMG 22940(T) (97.5?%), Burkholderia glathei DSM 50014(T) (97.4?%), Burkholderia terrestris LMG 22937(T) (97.2?%) and Burkholderia telluris LMG 22936(T) (97.0?%). In addition, the gyrB and recA gene segments of strain MP-1(T) exhibited less than 89.0?% and 95.1?% similarities with the most highly-related type strains indicated above. The G+C content of strain MP-1(T) was 62.6 mol%. The major isoprenoid quinone was ubiquinone Q-8. The predominant polar lipids comprised phosphatidyl ethanolamine, phosphatidyl glycerol, aminolipid and phospholipid. The principal fatty acids in strain MP-1(T) were C18?:?1?7c/C18?:?1?6c (23.3?%), C16?:?0 (16.8?%), cyclo-C17?:?0 (15.0?%), C16?:?1?7c/C16?:?1?6 (8.5?%), cyclo-C19?:?0?8c (8.1?%), C16?:?1 iso I/C14?:?0 3-OH (5.7?%), C16?:?0 3-OH (5.6?%) and C16?:?02-OH (5.1?%). The DNA-DNA relatedness values between strain MP-1(T) and the three type strains (B. grimmiae DSM 25160(T), B. zhejiangensis OP-1(T) and B. glathei DSM 50014(T)) ranged from 24.6?% to 37.4?%. In accordance with phenotypic and genotypic characteristics, strain MP-1(T) represents a novel species of the genus Burkholderia, for which the name Burkholderia jiangsuensis sp. nov. is proposed, the type strain is MP-1(T) (LMG 27927(T)?=?MCCC 1K00250(T)). PMID:24981326

Liu, Xu-Yun; Li, Chun-Xiu; Luo, Xiao-Jing; Lai, Qi-Liang; Xu, Jian-He

2014-09-01

372

9 CFR 121.6 - Exemptions for overlap select agents and toxins.  

Code of Federal Regulations, 2013 CFR

...toxins must be immediately reported by telephone, facsimile, or e-mail: Bacillus anthracis, Burkholderia mallei, and Burkholderia pseudomallei . This report must be followed by submission of APHIS/CDC Form 4 within 7 calendar days...

2013-01-01

373

42 CFR 73.6 - Exemptions for overlap select agents and toxins.  

Code of Federal Regulations, 2013 CFR

...toxins must be immediately reported by telephone, facsimile, or e-mail: Bacillus anthracis, Burkholderia mallei and Burkholderia pseudomallei . This report must be followed by submission of APHIS/CDC Form 4 within seven calendar...

2013-10-01

374

42 CFR 73.6 - Exemptions for overlap select agents and toxins.  

Code of Federal Regulations, 2014 CFR

...toxins must be immediately reported by telephone, facsimile, or e-mail: Bacillus anthracis, Burkholderia mallei and Burkholderia pseudomallei. This report must be followed by submission of APHIS/CDC Form 4 within seven calendar...

2014-10-01

375

dx/dt = ax bvx (equation 1) dy/dt = bvx by (equation 2)  

E-print Network

) Bacteriophage amplification and MALDI-TOF MS as a means of rapid Burkholderia pseudomallei diagnostic Burkholderia-specific bacteriophage X216 amplification assayed using phage-specific MALDI- TOF MS methods

376

CHLORINE INACTIVATION OF CATEGORY "A" BIO-TERRORISM AGENTS  

EPA Science Inventory

This poster presents information on the inactivation of select bioterrorist agents. Information will be presented on chlorine disinfection of vegetative cells of Brucella suis, Brucella melitensis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis and endos...

377

Diversity of Cultivated Endophytic Bacteria from Sugarcane: Genetic and Biochemical Characterization of Burkholderia cepacia Complex Isolates?  

PubMed Central

Bacteria were isolated from the rhizosphere and from inside the roots and stems of sugarcane plants grown in the field in Brazil. Endophytic bacteria were found in both the roots and the stems of sugarcane plants, with a significantly higher density in the roots. Many of the cultivated endophytic bacteria were shown to produce the plant growth hormone indoleacetic acid, and this trait was more frequently found among bacteria from the stem. 16S rRNA gene sequence analysis revealed that the selected isolates of the endophytic bacterial community of sugarcane belong to the genera of Burkholderia, Pantoea, Pseudomonas, and Microbacterium. Bacterial isolates belonging to the genus Burkholderia were the most predominant among the endophytic bacteria. Many of the Burkholderia isolates produced the antifungal metabolite pyrrolnitrin, and all were able to grow at 37°C. Phylogenetic analyses of the 16S rRNA gene and recA gene sequences indicated that the endophytic Burkholderia isolates from sugarcane are closely related to clinical isolates of the Burkholderia cepacia complex and clustered with B. cenocepacia (gv. III) isolates from cystic fibrosis patients. These results suggest that isolates of the B. cepacia complex are an integral part of the endophytic bacterial community of sugarcane in Brazil and reinforce the hypothesis that plant-associated environments may act as a niche for putative opportunistic human pathogenic bacteria. PMID:17905875

Mendes, Rodrigo; Pizzirani-Kleiner, Aline A.; Araujo, Welington L.; Raaijmakers, Jos M.

2007-01-01

378

Monitoring Therapeutic Treatments against Burkholderia Infections Using Imaging Techniques  

PubMed Central

Burkholderia mallei, the etiologic agent of glanders, are Category B select agents with biothreat potential, and yet effective therapeutic treatments are lacking. In this study, we showed that CpG administration increased survival, demonstrating protection in the murine glanders model. Bacterial recovery from infected lungs, liver and spleen was significantly reduced in CpG-treated animals as compared with non-treated mice. Reciprocally, lungs of CpG-treated infected animals were infiltrated with higher levels of neutrophils and inflammatory monocytes, as compared to control animals. Employing the B. mallei bioluminescent strain CSM001 and the Neutrophil-Specific Fluorescent Imaging Agent, bacterial dissemination and neutrophil trafficking were monitored in real-time using multimodal in vivo whole body imaging techniques. CpG-treatment increased recruitment of neutrophils to the lungs and reduced bioluminescent bacteria, correlating with decreased bacterial burden and increased protection against acute murine glanders. Our results indicate that protection of CpG-treated animals was associated with recruitment of neutrophils prior to infection and demonstrated, for the first time, simultaneous real time in vivo imaging of neutrophils and bacteria. This study provides experimental evidence supporting the importance of incorporating optimized in vivo imaging methods to monitor disease progression and to evaluate the efficacy of therapeutic treatment during bacterial infections. PMID:24349761

Mott, Tiffany M.; Johnston, R. Katie; Vijayakumar, Sudhamathi; Estes, D. Mark; Motamedi, Massoud; Sbrana, Elena; Endsley, Janice J.; Torres, Alfredo G.

2013-01-01

379

Identification of quorum sensing-controlled genes in Burkholderia ambifaria.  

PubMed

The Burkholderia cepacia complex (Bcc) comprises strains with a virulence potential toward immunocompromised patients as well as plant growth-promoting rhizobacteria (PGPR). Owing to the link between quorum sensing (QS) and virulence, most studies among Bcc species have been directed toward QS of pathogenic bacteria. We have investigated the QS of B. ambifaria, a PGPR only infrequently recovered from patients. The cepI gene, responsible for the synthesis of the main signaling molecule N-octanoylhomoserine lactone (C8 -HSL), was inactivated. Phenotypes of the B. ambifaria cepI mutant we observed, such as increased production of siderophores and decreased proteolytic and antifungal activities, are in agreement with those of other Bcc cepI mutants. The cepI mutant was then used as background strain for a whole-genome transposon-insertion mutagenesis strategy, allowing the identification of 20 QS-controlled genes, corresponding to 17 loci. The main functions identified are linked to antifungal and antimicrobial properties, as we have identified QS-controlled genes implicated in the production of pyrrolnitrin, burkholdines (occidiofungin-like molecules), and enacyloxins. This study provides insights in the QS-regulated functions of a PGPR, which could lead to beneficial potential biotechnological applications. PMID:23382083

Chapalain, Annelise; Vial, Ludovic; Laprade, Natacha; Dekimpe, Valérie; Perreault, Jonathan; Déziel, Eric

2013-04-01

380

Identification of quorum sensing-controlled genes in Burkholderia ambifaria  

PubMed Central

The Burkholderia cepacia complex (Bcc) comprises strains with a virulence potential toward immunocompromised patients as well as plant growth–promoting rhizobacteria (PGPR). Owing to the link between quorum sensing (QS) and virulence, most studies among Bcc species have been directed toward QS of pathogenic bacteria. We have investigated the QS of B. ambifaria, a PGPR only infrequently recovered from patients. The cepI gene, responsible for the synthesis of the main signaling molecule N-octanoylhomoserine lactone (C8-HSL), was inactivated. Phenotypes of the B. ambifaria cepI mutant we observed, such as increased production of siderophores and decreased proteolytic and antifungal activities, are in agreement with those of other Bcc cepI mutants. The cepI mutant was then used as background strain for a whole-genome transposon-insertion mutagenesis strategy, allowing the identification of 20 QS-controlled genes, corresponding to 17 loci. The main functions identified are linked to antifungal and antimicrobial properties, as we have identified QS-controlled genes implicated in the production of pyrrolnitrin, burkholdines (occidiofungin-like molecules), and enacyloxins. This study provides insights in the QS-regulated functions of a PGPR, which could lead to beneficial potential biotechnological applications. PMID:23382083

Chapalain, Annelise; Vial, Ludovic; Laprade, Natacha; Dekimpe, Valérie; Perreault, Jonathan; Déziel, Eric

2013-01-01

381

Toluene 2-Monooxygenase-Dependent Growth of Burkholderia cepacia G4/PR1 on Diethyl Ether  

PubMed Central

Aerobic bacterial growth on aromatic hydrocarbons typically requires oxygenase enzymes, which are known to fortuitously oxidize nongrowth substrates. In this study, we found that oxidation of diethyl ether by toluene 2-monooxygenase supported more rapid growth of Burkholderia cepacia G4/PR1 than did the aromatic substrates n-propylbenzene and o-xylene. The wild-type Burkholderia cepacia G4 failed to grow on diethyl ether. Purified toluene 2-monooxygenase protein components oxidized diethyl ether stoichiometrically to ethanol and acetaldehyde. Butyl methyl ether, diethyl sulfide, and 2-chloroethyl ethyl ether were oxidized by B. cepacia G4/PR1. PMID:16535583

Hur, H.; Newman, L. M.; Wackett, L. P.; Sadowsky, M. J.

1997-01-01

382

Synthesis of the trisaccharide outer core fragment of Burkholderia cepacia pv. vietnamiensis lipooligosaccharide.  

PubMed

The synthesis of ?-Gal-(1?3)-?-GalNAc-(1?3)-?-GalNAc allyl trisaccharide as the outer core fragment of Burkholderia cepacia pv. vietnamiensis lipooligosaccharide was accomplished through a concise, optimized, multi-step synthesis, having as key steps three glycosylations, that were in-depth studied performing them under several conditions. The target trisaccharide was designed with an allyl aglycone in order to open a future access to the conjugation with an immunogenic protein en route to the development of a synthetic neoglycoconjugate vaccine against this Burkholderia pathogen. PMID:22209378

Bedini, Emiliano; Cirillo, Luigi; Parrilli, Michelangelo

2012-02-15

383

Solubilization of insoluble inorganic phosphate by Burkholderia cepacia DA23 isolated from cultivated soil  

PubMed Central

A mineral phosphate solubilizing bacterium, Burkholderia cepacia DA23 has been isolated from cultivated soils. Phosphate-solubilizing activities of the strain against three types of insoluble phosphate were quantitatively determined. When 3% of glucose concentration was used for carbon source, the strain had a marked mineral phosphate-solubilizing activity. Mineral phosphate solubilization was directly related to the pH drop by the strain. Analysis of the culture medium by high pressure liquid chromatography identified gluconic acid as the main organic acid released by Burkholderia cepacia DA23. Gluconic acid production was apparently the result of the glucose dehydrogenase activity and glucose dehydrogenase was affected by phosphate regulation. PMID:24031195

Song, Ok-Ryul; Lee, Seung-Jin; Lee, Yong-Seok; Lee, Sang-Cheol; Kim, Keun-Ki; Choi, Yong-Lark

2008-01-01

384

Drosophila melanogaster as a Model Host for the Burkholderia cepacia Complex  

E-print Network

Drosophila melanogaster as a Model Host for the Burkholderia cepacia Complex Jose´e Castonguay with vertebrate organisms. Methodology/Principal Findings: The aim of this study was to establish Drosophila, validity of the Drosophila infection model was confirmed with B. cenocepacia K56-2 mutants known to be less

Paris-Sud XI, Université de

385

Genotypic Analysis of Burkholderia cepacia Isolates from 13 French Cystic Fibrosis Centers  

Microsoft Academic Search

Burkholderia cepacia has been involved in outbreaks of pulmonary infection among patients with cystic fibrosis (CF), and the spread of a highly transmissible clone has been reported throughout the United Kingdom and Canada. These data prompted a DNA-based typing study of the strains recovered in French CF centers. Ninety-five isolates recovered from 71 patients attending 13 CF centers in 9

CHRISTINE SEGONDS; EDOUARD BINGEN; GERARD COUETDIC; STEPHANIE MATHY; NAIMA BRAHIMI; NICOLE MARTY; PATRICK PLESIAT; YVON MICHEL-BRIAND; GERARD CHABANON; Hopital Robert Debre; CHU Jean Minjoz

1997-01-01

386

Energy-Generating Enzymes of Burkholderia cepacia and Their Interactions with Macrophages  

Microsoft Academic Search

We previously demonstrated that several clinical and environmental isolates of Burkholderia cepacia secreted ATP-utilizing enzymes to the medium; the secretion of these enzymes by cystic fibrosis lung isolate strain 38 was shown to be greatly enhanced in the presence of 2-macroglobulin. Fractionation of the growth medium of cystic fibrosis isolate strain 71 belonging to genomovar I demonstrated the presence of

Vasu Punj; Rachna Sharma; Olga Zaborina; A. M. Chakrabarty

2003-01-01

387

Concomitant Cryptococcosis and Burkholderia Infection in an Asymptomatic Lung Transplant Patient with Cystic Fibrosis  

PubMed Central

Concomitant pulmonary infections with Cryptococcus neoformans and Burkholderia cepacia in lung transplant recipients are very rare and create unique diagnostic and therapeutic dilemmas. Herein, we present a double lung transplant patient with cystic fibrosis who was found to have coinfection with these two rare organisms, though he was completely asymptomatic. PMID:25013584

Shafaghi, S.; Pour Abdollah, M.; Tabarsi, P.; Ghorbani, F.; Makki, S. S. M.; Khoddami Vishteh, H. R.; Faeghi, J.; Najafizadeh, K.

2010-01-01

388

Emergence of Burkholderia cepacia in Honolulu: a case of nursing home-acquired B. cepacia sepsis.  

PubMed

Burkholderia cepacia has rarely been reported in Honolulu. Its emergence as a nursing home-acquired pathogen with high mortality rate is concerning. This case report describes a local nursing home patient who was diagnosed with B. cepacia sepsis in 2012. PMID:24069571

Hua, Charles Nc; Tokeshi, Jinichi

2013-09-01

389

Adherence of Burkholderia cepacia to respiratory tract epithelial cells and inhibition with dextrans  

Microsoft Academic Search

Adherence of Burkholderia cepacia to cells of the respiratory tract of patients with cystic fibrosis (CF) appears to be a necessary precondition for colonization and infection. To date, no effective anti-adhesive strategy has been devised for preventing B. cepacia infection in CF patients. It was found in this study that B. cepacia adhered to respiratory epithelial cells both in vitro

Cheng-Hsun Chiu; Simon Wong; Robert E. W. Hancock; David P. Speert; Edward Jenner

390

The oxalic acid biosynthetic activity of Burkholderia mallei is encoded by a single locus.  

PubMed

Although it is known that oxalic acid provides a selective advantage to the secreting microbe our understanding of how this acid is biosynthesized remains incomplete. This study reports the identification, cloning, and partial characterization of the oxalic acid biosynthetic enzyme from the animal bacterial pathogen, Burkholderia mallei. The discovered gene was named oxalate biosynthetic component (obc)1. Complementation of Burkholderia oxalate defective (Bod)1, a Burkholderia glumae mutant that lacks expression of a functional oxalic acid biosynthetic operon, revealed that the obc1 was able to rescue the no oxalate mutant phenotype. This single gene rescue is in contrast to the situation found in B. glumae which required the expression of two genes, obcA and obcB, to achieve complementation. Enzyme assays showed that even though the two Burkholderia species differed in the number of genes required to encode a functional enzyme, both catalyzed the same acyl-CoA dependent biosynthetic reaction. In addition, mutagenesis studies suggested a similar domain structure of the assembled oxalate biosynthetic enzymes whether encoded by one or two genes. PMID:21242070

Nakata, Paul A

2011-10-20

391

NOVEL ORGANIZATION OF THE GENES FOR PHTHALATE DEGRADATION FROM BURKHOLDERIA CEPACIA DBO1  

EPA Science Inventory

Burkholderia cepacia DBO1 is able to utilize phthalate as the sole source of carbon and energy for growth. Two overlapping cosmid clones containing the genes for phthalate degradation were isolated from this strain. Subcloning and activity analysis localized the genes for phthala...

392

The relationship of biofilm production to biocontrol activity of Burkholderia pyrrocinia FP62  

Technology Transfer Automated Retrieval System (TEKTRAN)

Foliar biocontrol agent (BCA) efficacy is often inconsistent due to poor colonization and survival on plant surfaces. Burkholderia pyrrocinia FP62, a superior leaf colonist and BCA of Botrytis cinerea, forms unsaturated biofilms on plant surfaces. To determine the relationship between biocontrol act...

393

A bioinformatics approach to the determination of genes involved in endophytic behavior in Burkholderia spp.  

PubMed

The vast majority of plants harbor endophytic bacteria that colonize a portion of the plant's interior tissues without harming the plant. Like plant pathogens, endophytes gain entry into their plants hosts through various mechanisms. Bacterial endophytes display a broad range of symbiotic interactions with their host plants. The molecular bases of these plant-endophyte interactions are currently not fully understood. In the present study, a set of genes possibly responsible for endophytic behavior for genus Burkholderia was predicted and then compared and contrasted with a number (nine endophytes from different genera) of endophytes by comparative genome analysis. The nine endophytes included Burkholderia phytofirmans PsJN, Burkholderia spp. strain JK006, Azospirillum lipoferum 4B, Enterobacter cloacae ENHKU01, Klebsiella pneumoniae 342, Pseudomonas putida W619, Enterobacter spp. 638, Azoarcus spp. BH72, and Serratia proteamaculans 568. From the genomes of the analyzed bacterial strains, a set of bacterial genes orthologs was identified that are predicted to be involved in determining the endophytic behavior of Burkholderia spp. The genes and their possible functions were then investigated to establish a potential connection between their presence and the role they play in bacterial endophytic behavior. Nearly all of the genes identified by this bioinformatics procedure encode function previously suggested in other studies to be involved in endophytic behavior. PMID:24513137

Ali, Shimaila; Duan, Jin; Charles, Trevor C; Glick, Bernard R

2014-02-21

394

Draft Genome Sequence of an Aniline-Degrading Bacterium, Burkholderia sp. K24.  

PubMed

Burkholderia sp. K24 is an aniline-degrading soil bacterium that utilizes aniline and its analogues as sole carbon and nitrogen sources. Here, we report the draft genome sequence of this strain that consists of 8,344,181 bp, with a G+C content of 61.7%. PMID:25477408

Lee, Sang-Yeop; Yun, Sung Ho; Choi, Chi-Won; Lee, Dong-Gi; Choi, Jong Soon; Kahng, Hyung-Yeel; Kim, Seung Il

2014-01-01

395

South African Papilionoid Legumes Are Nodulated by Diverse Burkholderia with Unique Nodulation and  

E-print Network

and Nitrogen-Fixation Loci Chrizelle W. Beukes1 *, Stephanus N. Venter1 , Ian J. Law2 , Francina L. Phalane2 Legumes Are Nodulated by Diverse Burkholderia with Unique Nodulation and Nitrogen-Fixation Loci. PLoS ONE of horizontal gene transfer determining the symbiotic ability of these Cape Floristic Region isolates indicate

396

Effects of Rice Seed Surface Sterilization with Hypochlorite on Inoculated Burkholderia vietnamiensis  

Microsoft Academic Search

organism Burkholderia vietnamiensis TVV75. This artifact could not be eliminated simply by rinsing the seeds, even thoroughly, with sterile distilled water. When growth resumed, a significant increase in the frequency of rifampin- and nalidixic acid-resistant mutants in the population was observed compared to the control without seeds. This phenomenon was a specific effect of hypochlorite; it was not observed with

L. Miche; JACQUES BALANDREAU

2001-01-01

397

BioMed Central Page 1 of 11  

E-print Network

probe with each target. Results: Design of microarray probes for eight pathogenic Burkholderia genomes hybridize with non-targets. Also, more than 65% of the probes designed to identify all Burkholderia mallei and B. pseudomallei strains successfully hybridize with a B. pseudomallei strain not used for probe

398

Genetic diversity of Burkholderia (Proteobacteria) species from the Caatinga and Atlantic rainforest biomes in Bahia, Brazil.  

PubMed

The genus Burkholderia (?-Proteobacteria) currently comprises more than 60 species, including parasites, symbionts and free-living organisms. Several new species of Burkholderia have recently been described showing a great diversity of phenotypes. We examined the diversity of Burkholderia spp in environmental samples collected from Caatinga and Atlantic rainforest biomes of Bahia, Brazil. Legume nodules were collected from five locations, and 16S rDNA and recA genes of the isolated microorganisms were analyzed. Thirty-three contigs of 16S rRNA genes and four contigs of the recA gene related to the genus Burkholderia were obtained. The genetic dissimilarity of the strains ranged from 0 to 2.5% based on 16S rDNA analysis, indicating two main branches: one distinct branch of the dendrogram for the B. cepacia complex and another branch that rendered three major groups, partially reflecting host plants and locations. A dendrogram designed with sequences of this research and those designed with sequences of Burkholderia-type strains and the first hit BLAST had similar topologies. A dendrogram similar to that constructed by analysis of 16S rDNA was obtained using sequences of the fragment of the recA gene. The 16S rDNA sequences enabled sufficient identification of relevant similarities and groupings amongst isolates and the sequences that we obtained. Only 6 of the 33 isolates analyzed via 16S rDNA sequencing showed high similarity with the B. cepacia complex. Thus, over 3/4 of the isolates have potential for biotechnological applications. PMID:23546947

Santini, A C; Santos, H R M; Gross, E; Corrêa, R X

2013-01-01

399

Draft Genome Sequences of Two Burkholderia multivorans Sequential Isolates from a Chronic Lung Infection of a Cystic Fibrosis Patient  

PubMed Central

Burkholderia multivorans belongs to the Burkholderia cepacia complex, which comprises opportunistic pathogens infecting cystic fibrosis (CF) patients. Here, we report the genome sequences and annotations of two sequential B. multivorans clinical isolates (D2095 and D2214) displaying different traits. The differences in the genomic contents of these isolates may provide clues regarding the evolution of B. multivorans within the airways of a CF patient. PMID:25676757

Silva, Inês N.; Santos, Pedro M.

2015-01-01

400

Enhancement of Burkholderia cepacia antimicrobial susceptibility by cationic compounds.  

PubMed

Infections in cystic fibrosis (CF) due to Burkholderia cepacia are challenging due to their resistance to antibiotics. We explored a new strategy for increasing the permeability of B. cepacia using cationic agents, including amino compounds, to reduce the MICs of standard antibiotics. Twenty-eight B. cepacia isolates from four CF centres in North America and four non-CF B. cepacia were examined by standard microtitre broth dilution methods for susceptibility to a variety of antibiotics in the presence of non-inhibitory concentrations of diaminoacetone (DAA), methylglyoxal bis-guanylhydrazone (MGBH), chlorpromazine (CPZ) and prochlorperazine (PCPZ). The proportion of isolates with greater than four-fold reductions in MIC in the presence of 0.3 mM CPZ or 0.4 mM PCPZ were 90% and 94% for gentamicin, 80% and 83% for tobramycin, 45% and 17% for ceftazidime, and 35% and 17% for amifloxacin. CPZ showed the same degree of reduction in the MIC of azithromycin in 79% strains (MIC50 reduced to 16 from > or = 256 mg/L). Non-CF B. cepacia showed a greater than four-fold reduction in MIC with CPZ for gentamicin, tobramycin and azithromycin and two-fold reduction for ceftazidime. Little or no reduction in MIC was seen with DAA or MGBH for any antibiotic. Addition of magnesium ions to the medium competitively inhibited any MIC reduction effect seen with the cationic agents. CPZ and PCPZ appeared to enhance the permeability of B. cepacia to antibiotics based upon ionic charge characteristics of the antibiotic. No significant differences were seen in outer membrane protein and lipopolysaccharide profiles between the culture treated with CPZ and the respective control culture of strain B. cepacia ATCC 13945. The fluorescent probe 1N-phenylnaphthylamine had no increased access across the outer membrane in the presence of CPZ for B. cepacia ATCC 13945. However, thin-section electron microscopy revealed separation between the outer membrane and the rest of the cytoplasm accompanied by a widening of the periplasmic space. These data provide a rationale for investigating amino compounds as potential permeability-increasing agents against B. cepacia. PMID:9338485

Rajyaguru, J M; Muszynski, M J

1997-09-01

401

Bioassay-guided isolation of a low molecular weight PHB from Burkholderia sp. with phytotoxic activity.  

PubMed

This work reports on the bioassay-guided isolation and identification of the macrocyclic pentolide 1, a cyclic polyhydroxybutyrate (PHB) with low molecular weight. This metabolite is produced by Burkholderia sp. and it exhibited phytotoxic activity in a Lemna minor bioassay. Its structure was determined by (1)H and (13)C NMR, heteronuclear multiple quantum correlation, heteronuclear multiple bond correlation, IR, and electrospray ionization tandem mass spectrometry analyses. The period for maximum production of the pentolide was optimized and determined on the basis of multiple reaction monitoring experiments at 15 days. The potential of Burkholderia sp. as a producer of higher biopolymers of PHB was also investigated. The methodology employed here accelerated the isolation and characterization of a phytotoxic metabolite whose structure can serve as a model for the synthesis of new classes of herbicides. PMID:23722946

Petta, Tânia; Raichardt, Leandro; Melo, Itamar S; Moraes, Luiz A B

2013-08-01

402

Genome sequence of the Lebeckia ambigua-nodulating “Burkholderia sprentiae” strain WSM5005T  

PubMed Central

Burkholderia sprentiae” strain WSM5005T is an aerobic, motile, Gram-negative, non-spore-forming rod that was isolated in Australia from an effective N2-fixing root nodule of Lebeckia ambigua collected in Klawer, Western Cape of South Africa, in October 2007. Here we describe the features of “Burkholderia sprentiae” strain WSM5005T, together with the genome sequence and its annotation. The 7,761,063 bp high-quality-draft genome is arranged in 8 scaffolds of 236 contigs, contains 7,147 protein-coding genes and 76 RNA-only encoding genes, and is one of 20 rhizobial genomes sequenced as part of the DOE Joint Genome Institute 2010 Community Sequencing Program. PMID:24976894

Reeve, Wayne; De Meyer, Sofie; Terpolilli, Jason; Melino, Vanessa; Ardley, Julie; Rui, Tian; Tiwari, Ravi; Howieson, John; Yates, Ron; O’Hara, Graham; Lu, Megan; Bruce, David; Detter, Chris; Tapia, Roxanne; Han, Cliff; Wei, Chia-Lin; Huntemann, Marcel; Han, James; Chen, I-Min; Mavromatis, Konstantinos; Markowitz, Victor; Szeto, Ernest; Ivanova, Natalia; Mikhailova, Natalia; Ovchinnikova, Galina; Pagani, Ioanna; Pati, Amrita; Goodwin, Lynne; Peters, Lin; Pitluck, Sam; Woyke, Tanja; Kyrpides, Nikos

2013-01-01

403

Antimicrobial activities of LL-37 and its truncated variants against Burkholderia thailandensis.  

PubMed

Antimicrobial peptides (AMPs) are essential host defence molecules found in a wide variety of species and are promising antibacterial therapeutic candidates. Focusing on the human cathelicidin peptide LL-37, the aim of the present study was to explore the mechanisms of action and antimicrobial activities of a library of LL-37 fragments using Burkholderia thailandensis E264 as a model. The results revealed that IG-19 was the shortest fragment within LL-37 that exhibited antibacterial activity. LL-31, missing six residues at the C-terminus of LL-37, exhibited the strongest killing effect. Freeze-fracture electron microscopy of bacterial cells treated with either LL-37 or LL-31 revealed irregular bacterial surfaces with bleb projections, indicating that these peptides disrupted the integrity of the membrane. In addition, these peptides induced leakage of cell components, including nucleotides and even proteins. Altogether, the results obtained indicate the potential of using LL-31 as a new AMP to combat Burkholderia spp. PMID:20685090

Kanthawong, Sakawarat; Bolscher, Jan G M; Veerman, Enno C I; van Marle, Jan; Nazmi, Kamran; Wongratanacheewin, Surasakdi; Taweechaisupapong, Suwimol

2010-11-01

404

Synthesis of the tetrasaccharide outer core fragment of Burkholderia multivorans lipooligosaccharide.  

PubMed

The first synthesis of the outer core fragment of Burkholderia multivorans lipooligosaccharide [?-d-Glc-(1?3)-?-d-GalNAc-(1?3)-?-d-GalNAc-(1?3)-l-Rha] as ?-allyl tetrasaccharide was accomplished. The glycosylations involving GalNAc units were studied in depth testing them under several conditions. This allowed the building of both the ?- and the ?-configured glycosidic bonds by employing the same GalNAc glycosyl donor, thus considerably shortening the total number of synthetic steps. The target tetrasaccharide was synthesized with an allyl aglycone to allow its future conjugation with an immunogenic protein en route to the development of a synthetic neoglycoconjugate vaccine against the Burkholderia cepacia pathogens. PMID:24933233

Ziaco, Marcello; De Castro, Cristina; Silipo, Alba; Corsaro, Maria Michela; Molinaro, Antonio; Iadonisi, Alfonso; Lanzetta, Rosa; Parrilli, Michelangelo; Bedini, Emiliano

2015-02-11

405

Total protein extraction and 2-D gel electrophoresis methods for Burkholderia species.  

PubMed

The investigation of the intracellular protein levels of bacterial species is of importance to understanding the pathogenic mechanisms of diseases caused by these organisms. Here we describe a procedure for protein extraction from Burkholderia species based on mechanical lysis using glass beads in the presence of ethylenediamine tetraacetic acid and phenylmethylsulfonyl fluoride in phosphate buffered saline. This method can be used for different Burkholderia species, for different growth conditions, and it is likely suitable for the use in proteomic studies of other bacteria. Following protein extraction, a two-dimensional (2-D) gel electrophoresis proteomic technique is described to study global changes in the proteomes of these organisms. This method consists of the separation of proteins according to their isoelectric point by isoelectric focusing in the first dimension, followed by separation on the basis of molecular weight by acrylamide gel electrophoresis in the second dimension. Visualization of separated proteins is carried out by silver staining. PMID:24192802

Velapatiño, Billie; Zlosnik, James E A; Hird, Trevor J; Speert, David P

2013-01-01

406

Burkholderia insulsa sp. nov., a facultatively chemolithotrophic bacterium isolated from an arsenic-rich shallow marine hydrothermal system.  

PubMed

Enrichment cultures inoculated with hydrothermally influenced nearshore sediment from Papua New Guinea led to the isolation of an arsenic-tolerant, acidophilic, facultatively aerobic bacterial strain designated PNG-April(T). Cells of this strain were Gram-stain-negative, rod-shaped, motile and did not form spores. Strain PNG-April(T) grew at temperatures between 4 °C and 40 °C (optimum 30-37 °C), at pH 3.5 to 8.3 (optimum pH 5-6) and in the presence of up to 2.7?% NaCl (optimum 0-1.0?%). Both arsenate and arsenite were tolerated up to concentrations of at least 0.5 mM. Metabolism in strain PNG-April(T) was strictly respiratory. Heterotrophic growth occurred with O2 or nitrate as electron acceptors, and aerobic lithoautotrophic growth was observed with thiosulfate or nitrite as electron donors. The novel isolate was capable of N2-fixation. The respiratory quinones were Q-8 and Q-7. Phylogenetically, strain PNG-April(T) belongs to the genus Burkholderia and shares the highest 16S rRNA gene sequence similarity with the type strains of Burkholderia fungorum (99.8?%), Burkholderia phytofirmans (98.8?%), Burkholderia caledonica (98.4?%) and Burkholderia sediminicola (98.4?%). Differences from these related species in several physiological characteristics (lipid composition, carbohydrate utilization, enzyme profiles) and DNA-DNA hybridization suggested the isolate represents a novel species of the genus Burkholderia, for which we propose the name Burkholderia insulsa sp. nov. The type strain is PNG-April(T) (?=?DSM 28142(T)?=?LMG 28183(T)). PMID:25323596

Rusch, Antje; Islam, Shaer; Savalia, Pratixa; Amend, Jan P

2015-01-01

407

Burkholderia sp. induces functional nodules on the South African invasive legume Dipogon lignosus (Phaseoleae) in New Zealand soils.  

PubMed

The South African invasive legume Dipogon lignosus (Phaseoleae) produces nodules with both determinate and indeterminate characteristics in New Zealand (NZ) soils. Ten bacterial isolates produced functional nodules on D. lignosus. The 16S ribosomal RNA (rRNA) gene sequences identified one isolate as Bradyrhizobium sp., one isolate as Rhizobium sp. and eight isolates as Burkholderia sp. The Bradyrhizobium sp. and Rhizobium sp. 16S rRNA sequences were identical to those of strains previously isolated from crop plants and may have originated from inocula used on crops. Both 16S rRNA and DNA recombinase A (recA) gene sequences placed the eight Burkholderia isolates separate from previously described Burkholderia rhizobial species. However, the isolates showed a very close relationship to Burkholderia rhizobial strains isolated from South African plants with respect to their nitrogenase iron protein (nifH), N-acyltransferase nodulation protein A (nodA) and N-acetylglucosaminyl transferase nodulation protein C (nodC) gene sequences. Gene sequences and enterobacterial repetitive intergenic consensus (ERIC) PCR and repetitive element palindromic PCR (rep-PCR) banding patterns indicated that the eight Burkholderia isolates separated into five clones of one strain and three of another. One strain was tested and shown to produce functional nodules on a range of South African plants previously reported to be nodulated by Burkholderia tuberum STM678(T) which was isolated from the Cape Region. Thus, evidence is strong that the Burkholderia strains isolated here originated in South Africa and were somehow transported with the plants from their native habitat to NZ. It is possible that the strains are of a new species capable of nodulating legumes. PMID:24801964

Liu, Wendy Y Y; Ridgway, Hayley J; James, Trevor K; James, Euan K; Chen, Wen-Ming; Sprent, Janet I; Young, J Peter W; Andrews, Mitchell

2014-10-01

408

Mechanism of Resistance to an Antitubercular 2-Thiopyridine Derivative That Is Also Active against Burkholderia cenocepacia  

PubMed Central

The discovery of new compounds that are able to inhibit the growth of Burkholderia cenocepacia is of primary importance for cystic fibrosis patients. Here, the mechanism of resistance to a new pyridine derivative already shown to be effective against Mycobacterium tuberculosis and to have good activity toward B. cenocepacia was investigated. Increased expression of a resistance-nodulation-cell division (RND) efflux system was detected in the resistant mutants, thus confirming their important roles in B. cenocepacia antibiotic resistance. PMID:24395233

Scoffone, Viola C.; Spadaro, Francesca; Udine, Claudia; Makarov, Vadim; Fondi, Marco; Fani, Renato; De Rossi, Edda; Riccardi, Giovanna

2014-01-01

409

Gentamicin Delivery to Burkholderia cepacia Group IIIa Strains via Membrane Vesicles from Pseudomonas aeruginosa PAO1  

Microsoft Academic Search

When Pseudomonas aeruginosa PAO1 is treated with gentamicin, it releases membrane vesicles containing gentamicin (g-MVs) and peptidoglycan hydrolase, which makes the MVs bactericidal. We evaluate the ability of g-MVs to deliver gentamicin past the intrinsic permeability barrier of group IIIa Burkholderia cepacia and show that strain CEP0248 with low resistance to gentamicin is killed but the highly resistant strain C5424

Nick D. Allan; Terry J. Beveridge

2003-01-01

410

Role of lipase in Burkholderia cepacia complex (Bcc) invasion of lung epithelial cells  

Microsoft Academic Search

The Burkholderia cepacia complex (Bcc) is a group of ten closely related species associated with life-threatening infection in cystic fibrosis (CF).\\u000a These bacteria are highly antibiotic resistant, with some strains transmissible, and in a subgroup of patients, they can cause\\u000a a rapid and fatal necrotising pneumonia. The Bcc organisms produce a range of exoproducts with virulence potential, including\\u000a exopolysaccharide, proteases

T. Mullen; K. Markey; P. Murphy; S. McClean; M. Callaghan

2007-01-01

411

Structural characterization of an acidic exoheteropolysaccharide produced by the nitrogen-fixing bacterium Burkholderia tropica  

Microsoft Academic Search

An acidic exopolysaccharide (EPS) produced by the diazotrophic bacterium Burkholderia tropica, strain Ppe8, was isolated from the culture supernatant of bacteria grown in a synthetic liquid medium containing mannitol and glutamate. Monosaccharide composition showed Rha, Glc and GlcA in a 2.0:2.0:1.0 molar ratio, respectively. Further structural characterization was performed by a combination of NMR, mass spectrometry and chemical methods. Partial

Rodrigo V. Serrato; Guilherme L. Sassaki; Philip A. J. Gorin; Leonardo M. Cruz; Fábio O. Pedrosa; Biswa Choudhury; Russell W. Carlson; Marcello Iacomini

2008-01-01

412

An outbreak of Burkholderia cenocepacia associated with contaminated chlorhexidine solutions prepared in the hospital.  

PubMed

From October to December 2007, an outbreak of Burkholderia cenocepacia occurred in a secondary care hospital. The 19 B cenocepacia isolated from the patients, the chlorhexidine solutions of each different ward, and the purified water that diluted these solutions exhibited an identical pulsed-field gel electrophoresis pattern. Inadequate preparation of chlorhexidine solutions diluted with contaminated purified water may have resulted in an outbreak of B cenocepacia. Adequate preparation of chlorhexidine solutions should be emphasized. PMID:23608047

Lee, Shinwon; Han, Seung Woo; Kim, Gunwoo; Song, Do Young; Lee, Je Chul; Kwon, Ki Tae

2013-09-01

413

Performance of MALDI-ToF MS for species identification of Burkholderia cepacia complex clinical isolates.  

PubMed

We evaluated the performance of matrix-assisted laser desorption ionization-time of flight (MALDI-ToF) for identification of Bcc species compared with that of recA sequencing. MALDI-ToF was able of identifying 100% of Bcc isolates at the genus level, but 23.1% of Bcc isolates tested were not correctly identified at the species level. The misidentification occurred most frequently with Burkholderia contaminans (100%) and B. cepacia (33.3%). PMID:23891221

Fehlberg, Lorena Cristina Corrêa; Andrade, Lucas Henrique Sales; Assis, Diego Magno; Pereira, Rosana Helena Vicente; Gales, Ana Cristina; Marques, Elizabeth Andrade

2013-10-01

414

Quorum Sensing in Burkholderia cepacia: Identification of the LuxRI Homologs CepRI  

Microsoft Academic Search

Burkholderia cepacia has emerged as an important pathogen in patients with cystic fibrosis. Many gram- negative pathogens regulate the production of extracellular virulence factors by a cell density-dependent mech- anism termed quorum sensing, which involves production of diffusible N-acylated homoserine lactone signal molecules, called autoinducers. Transposon insertion mutants of B. cepacia K56-2 which hyperproduced sidero- phores on chrome azurol S

SHAWN LEWENZA; BARBARA CONWAY; E. P. GREENBERG; PAMELA A. SOKOL

1999-01-01

415

Identification of Burkholderia spp. in the clinical microbiology laboratory: comparison of conventional and molecular methods  

Microsoft Academic Search

Cystic fibrosis (CF) predisposes patients to bacterial colonization and\\u000a infection of the lower airways. Several species belonging to the genus\\u000a Burkholderia are potential CF-related pathogens, but microbiological\\u000a identification may be complicated. This situation is not in the least due\\u000a to the poorly defined taxonomic status of these bacteria, and further\\u000a validation of the available diagnostic assays is required. A total

Pelt van C; C. M. Verduin; W. H. F. Goessens; M. C. Vos; B. Tummler; C. Segonds; F. Reubsaet; Belkum van A. F; H. A. Verbrugh

1999-01-01

416

Global Distribution and Evolution of a Toxinogenic Burkholderia-Rhizopus Symbiosis?†  

PubMed Central

Toxinogenic endobacteria were isolated from a collection of Rhizopus spp. representing highly diverse geographic origins and ecological niches. All endosymbionts belonged to the Burkholderia rhizoxinica complex according to matrix-assisted laser desorption ionization-time of flight biotyping and multilocus sequence typing, suggesting a common ancestor. Comparison of host and symbiont phylogenies provides insights into possible cospeciation and horizontal-transmission events. PMID:19286793

Lackner, Gerald; Möbius, Nadine; Scherlach, Kirstin; Partida-Martinez, Laila P.; Winkler, Robert; Schmitt, Imke; Hertweck, Christian

2009-01-01

417

Nodulation in black locust by the Gammaproteobacteria Pseudomonas sp. and the Betaproteobacteria Burkholderia sp.  

PubMed

Nodulation abilities of bacteria in the subclasses Gammaproteobacteria and Betaproteobacteria on black locust (Robinia pseudoacacia) were tested. Pseudomonas sp., Burkholderia sp., Klebsiella sp., and Paenibacillus sp. were isolated from surface-sterilized black locust nodules, but their nodulation ability is unknown. The aims of this study were to determine if these bacteria are symbiotic. The species and genera of the strains were determined by RFLP analysis and DNA sequencing of 16S rRNA gene. Inoculation tests and histological studies revealed that Pseudomonas sp. and Burkholderia sp. formed nodules on black locust and also developed differentiated nodule tissue. Furthermore, a phylogenetic analysis of nodA and a BLASTN analysis of the nodC, nifH, and nifHD genes revealed that these symbiotic genes of Pseudomonas sp. and Burkholderia sp. have high similarities with those of rhizobial species, indicating that the strains acquired the symbiotic genes from rhizobial species in the soil. Therefore, in an actual rhizosphere, bacterial diversity of nodulating legumes may be broader than expected in the Alpha-, Beta-, and Gammaproteobacteria subclasses. The results indicate the importance of horizontal gene transfer for establishing symbiotic interactions in the rhizosphere. PMID:20542651

Shiraishi, Ayami; Matsushita, Norihisa; Hougetsu, Taizo

2010-08-01

418

Structure of a novel exopolysaccharide produced by Burkholderia vietnamiensis, a cystic fibrosis opportunistic pathogen.  

PubMed

Burkholderia vietnamiensis belongs to the Burkholderia cepacia complex and is an opportunistic pathogen for cystic fibrosis patients. As many other Burkholderia species, it has a mucoide phenotype, producing abundant exopolysaccharide. In general, polysaccharides contribute to bacterial survival in a hostile environment, are recognised as virulence factors and as important components in biofilm formation. The primary structure of the exopolysaccharide produced by B. vietnamiensis LMG 10929 was determined mainly by use of 1D and 2D NMR spectroscopy and ESI mass spectrometry. The polymer consists of the trisaccharidic backbone 3)-?-D-Glcp-(1?4)-?-D-Glcp-(1?3)-?-L-Fucp-(1? with the side chain ?-D-Glcp-(1?4)-?-D-GlcAp-(1?3)-?-L-Fucp-(1? linked to C-3 of the ?-D-Glcp residue. The polysaccharide also bears acetyl substituents on about 20% of its repeating units and on at least two different positions. The presence of fucose residues is a novel structural feature among the exopolysaccharides produced by species of the B. cepacia complex. PMID:23544536

Cescutti, Paola; Cuzzi, Bruno; Herasimenka, Yury; Rizzo, Roberto

2013-04-15

419

MtvR is a global small noncoding regulatory RNA in Burkholderia cenocepacia.  

PubMed

Burkholderia cenocepacia J2315 is a highly epidemic and transmissible clinical isolate of the Burkholderia cepacia complex (Bcc), a group of bacteria causing life-threatening respiratory infections among cystic fibrosis patients. This work describes the functional analysis of the 136-nucleotide (nt)-long MtvR small noncoding RNA (sRNA) from the Bcc member B. cenocepacia J2315, with homologues restricted to the genus Burkholderia. Bioinformatic target predictions revealed a total of 309 mRNAs to be putative MtvR targets. The mRNA levels corresponding to 17 of 19 selected genes were found to be affected when MtvR was either overexpressed or silenced. Analysis of the interaction between MtvR and the hfq mRNA, one of its targets, showed that the sRNA binds exclusively to the 5' untranslated region (UTR) of the hfq mRNA. This interaction resulted in decreased protein synthesis, suggesting a negative regulatory effect of MtvR on the RNA chaperone Hfq. Bacterial strains with MtvR silenced or overexpressed exhibited pleiotropic phenotypes related to growth and survival after several stresses, swimming and swarming motilities, biofilm formation, resistance to antibiotics, and ability to colonize and kill the nematode Caenorhabditis elegans. Together, the results indicate that the MtvR sRNA is a major posttranscriptional regulator in B. cenocepacia. PMID:23729649

Ramos, Christian G; Grilo, André M; da Costa, Paulo J P; Feliciano, Joana R; Leitão, Jorge H

2013-08-01

420

A novel siderophore-independent strategy of iron uptake in the genus Burkholderia.  

PubMed

Like many other bacteria, Burkholderia sp. take up iron in its ferric form via siderophore-dependent transporters. We observed that mutant strains of B. cenocepacia?H111 unable to synthesize siderophores did not exhibit any growth defect under iron limited conditions. This finding suggested that this opportunistic pathogen can adopt an alternative iron uptake strategy to compensate for the loss of siderophores. We identified a putative iron uptake locus, ftrBcc ABCD, in the genome of B. cenocepacia?H111, which is also conserved in other members of the genus Burkholderia. Mutants deficient in both siderophore-dependent and FtrBcc ABCD systems failed to grow under iron-limited conditions and radiolabelled iron transport assays showed that these mutants were impaired in iron uptake. In addition, expression of ftrBcc ABCD can restore growth of an E. coli strain lacking all known high-affinity iron transport systems under iron-limited conditions. We show that all four proteins encoded by ftrBcc ABCD are essential for iron uptake. Furthermore, our results indicate that the expression of ftrBcc ABCD is regulated at the transcriptional level by iron concentration. This study provides evidence of an alternative, siderophore-independent, iron uptake system in Burkholderia species. PMID:24354890

Mathew, Anugraha; Eberl, Leo; Carlier, Aurelien L