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two cases of burkholderia cenocepacia in septicemic patients.we herein report repeated isolation of burkholderia cenocepacia from two cases of septicemia admitted to cardiothoracic and bone marrow transplant (bmt) units. the two blood cultures taken from each patient grew b. cenocepacia. both patients turned afebrile after appropriate antimicrobial therapy, and the subsequent blood cultures were sterile. however, both patients had recurrence of fever after about a week, and the patient in the bmt unit died due to respiratory failure. environmental surveil ...200818362403
liposomal bismuth-ethanedithiol formulation enhances antimicrobial activity of tobramycin.pseudomonas aeruginosa and burkholderia cenocepacia (formally, genomovar iii genotype of burkholderia cepacia complex) have emerged as serious opportunistic resistant pathogens in patients with cystic fibrosis (cf). we have developed a liposomal formulation containing bismuth-ethanedithiol (biedt) and tobramycin to overcome bacterial resistance. the stability of liposomal biedt-tobramycin (lipobiedt-tob) was studied in phosphate buffered saline (pbs) and human pooled plasma at 4 and 37 degrees c ...200818448284
in vitro interactions of tobramycin with various nonantibiotics against pseudomonas aeruginosa and burkholderia cenocepacia.pseudomonas aeruginosa and burkholderia cepacia are the major pathogens that colonize the airway surface and cause progressive respiratory failure and high mortality, especially in cystic fibrosis (cf) patients. tobramycin is the treatment of choice, but persistent usage enables the infectious organisms to activate defence mechanisms, making eradication rarely successful. combinations of antibiotic and nonantibiotic compounds have been tested in vitro against p. aeruginosa and b. cepacia, but wi ...200818513356
bacteria of the burkholderia cepacia complex are cyanogenic under biofilm and colonial growth conditions.the burkholderia cepacia complex (bcc) is a collection of nine genotypically distinct but phenotypically similar species. they show wide ecological diversity and include species that are used for promoting plant growth and bio-control as well species that are opportunistic pathogens of vulnerable patients. over recent years the bcc have emerged as problematic pathogens of the cf lung. pseudomonas aeruginosa is another important cf pathogen. it is able to synthesise hydrogen cyanide (hcn), a pote ...200818588687
cystic fibrosis, a burkholderia cenocepacia chest wall abscess and rapid clinical deterioration. 200818607020
differential modulation of innate immune cell functions by the burkholderia cepacia complex: burkholderia cenocepacia but not burkholderia multivorans disrupts maturation and induces necrosis in human dendritic cells.burkholderia cepacia complex (bcc) bacteria cause pulmonary infections that can evolve into fatal overwhelming septicemia in chronic granulomatous disease or cystic fibrosis patients. burkholderia cenocepacia and burkholderia multivorans are responsible for the majority of bcc infections in cystic fibrosis patients, but b. cenocepacia is generally associated with a poorer prognosis than b. multivorans. the present study investigated whether these pathogens could modulate the normal functions of ...200818624797
burkholderia cenocepacia strains isolated from cystic fibrosis patients are apparently more invasive and more virulent than rhizosphere strains.given the widespread presence of burkholderia cenocepacia in the rhizosphere it is important to determine whether rhizosphere strains are pathogenic for cystic fibrosis patients or not. eighteen b. cenocepacia strains of rhizosphere and clinical origin were typed by multi-locus sequence typing (mlst) analysis and compared for their ability to invade pulmonary epithelial cells and their virulence in a mouse model of airway infection. although there was great variability, clinical strains were the ...200818643926
detection of n-acyl homoserine lactones using a trai-luxcdabe-based biosensor as a high-throughput screening tool.bacteria use n-acyl homoserine lactone (ahl) molecules to regulate the expression of genes in a density-dependent manner. several biosensors have been developed and engineered to detect the presence of all types of ahls.200818667064
plant host and sugar alcohol induced exopolysaccharide biosynthesis in the burkholderia cepacia complex.the species that presently constitute the burkholderia cepacia complex (bcc) have multiple roles; they include soil and water saprophytes, bioremediators, and plant, animal and human pathogens. since the first description of pathogenicity in the bcc was based on sour skin rot of onion bulbs, this study returned to this plant host to investigate the onion-associated phenotype of the bcc. many bcc isolates, which were previously considered to be non-mucoid, produced copious amounts of exopolysacch ...200818667584
functional analysis of the burkholderia cenocepacia j2315 bceaj protein with phosphomannose isomerase and gdp-d-mannose pyrophosphorylase activities.the bcea(j) gene from the cystic fibrosis isolate burkholderia cenocepacia j2315 encodes a 56-kda bifunctional protein, with phosphomannose isomerase (pmi) and guanosine diphosphate (gdp)-mannose pyrophosphorylase (gmp) activities, a new member of the poorly characterised type ii pmi class of proteins. due to the lack of homology between the type ii pmis and the human pmi, this class of proteins are being regarded as interesting potential targets to develop new antimicrobials. the bcea(j) protei ...200818668237
tlr 5, but neither tlr2 nor tlr4, is involved in lung epithelial cell response to burkholderia cenocepacia.burkholderia cenocepacia is known to induce a harmful inflammatory response in the airways of cystic fibrosis patients. toll-like receptors (tlrs) play key roles in sensing microbial-associated molecular patterns and initiating host innate immunity, but their role in the inflammatory response elicited by b. cenocepacia has not been precisely examined. in this study, we evaluated the contribution of tlr2, tlr4 and tlr5 to the signaling pathways triggered by b. cenocepacia in human bronchial epith ...200818680520
burkholderia cenocepacia j2315 acyl carrier protein: a potential target for antimicrobials' development?this work describes the isolation and characterization of an acyl carrier protein (acp) mutant from burkholderia cenocepacia j2315, a strain of the burkholderia cepacia complex (bcc). bcc comprises at least 9 species that emerged as opportunistic pathogens able to cause life-threatening infections, particularly severe among cystic fibrosis patients. bacterial acps are the donors of the acyl moiety involved in the biosynthesis of fatty acids, which play a central role in metabolism. the mutant wa ...200818771721
a functional phenylacetic acid catabolic pathway is required for full pathogenicity of burkholderia cenocepacia in the caenorhabditis elegans host model.burkholderia cenocepacia is a member of the burkholderia cepacia complex, a group of metabolically versatile bacteria that have emerged as opportunistic pathogens in cystic fibrosis and immunocompromised patients. previously a screen of transposon mutants in a rat pulmonary infection model identified an attenuated mutant with an insertion in paae, a gene related to the phenylacetic acid (pa) catabolic pathway. in this study, we characterized gene clusters involved in the pa degradation pathway o ...200818776009
gene expression changes linked to antimicrobial resistance, oxidative stress, iron depletion and retained motility are observed when burkholderia cenocepacia grows in cystic fibrosis sputum.bacteria from the burkholderia cepacia complex (bcc) are the only group of cystic fibrosis (cf) respiratory pathogens that may cause death by an invasive infection known as cepacia syndrome. their large genome (> 7000 genes) and multiple pathways encoding the same putative functions make virulence factor identification difficult in these bacteria.200818801206
a type iv secretion system contributes to intracellular survival and replication of burkholderia cenocepacia.burkholderia cenocepacia is an important respiratory pathogen in persons with cystic fibrosis (cf). recent studies indicate that b. cenocepacia survives within macrophages and airway epithelial cells in vitro by evading endosome-lysosome fusion. we investigated the role of a plasmid-encoded type iv secretion system in the intracellular survival, replication, and processing of b. cenocepacia. both a wild-type strain (k56-2) and its type iv secretion system mutant (designated lc101) entered and re ...200818824538
evaluation of the efficacy of disinfection procedures against burkholderia cenocepacia biofilms.summary: in the present study we evaluated the efficacy of various procedures recommended for the disinfection of respiratory equipment and other materials in cystic fibrosis, using both planktonic and sessile burkholderia cenocepacia cells. a modified european suspension test was performed to determine the effects of the disinfection procedures on planktonic cells. the ability of the treatments to kill sessile cells and to remove biofilm biomass was evaluated using two resazurin-based viability ...200818977555
burkholderia cenocepacia-induced delay of acidification and phagolysosomal fusion in cystic fibrosis transmembrane conductance regulator (cftr)-defective macrophages.the burkholderia cepacia complex (bcc) is a group of opportunistic bacteria chronically infecting the airways of patients with cystic fibrosis (cf). several laboratories have shown that bcc members, in particular b. cenocepacia, survive within a membrane-bound vacuole inside phagocytic and epithelial cells. we have previously demonstrated that intracellular b. cenocepacia causes a delay in phagosomal maturation, as revealed by impaired acidification and slow accumulation of the late phagolysosom ...200819047750
genomic sequence and activity of ks10, a transposable phage of the burkholderia cepacia complex.the burkholderia cepacia complex (bcc) is a versatile group of gram negative organisms that can be found throughout the environment in sources such as soil, water, and plants. while bcc bacteria can be involved in beneficial interactions with plants, they are also considered opportunistic pathogens, specifically in patients with cystic fibrosis and chronic granulomatous disease. these organisms also exhibit resistance to many antibiotics, making conventional treatment often unsuccessful. ks10 wa ...200819094239
mannosylated poly(ethylene oxide)-b-poly(epsilon-caprolactone) diblock copolymers: synthesis, characterization, and interaction with a bacterial lectin.a novel bioeliminable amphiphilic poly(ethylene oxide)-b-poly(epsilon-caprolactone) (peo-b-pcl) diblock copolymer end-capped by a mannose residue was synthesized by sequential controlled polymerization of ethylene oxide and epsilon-caprolactone, followed by the coupling of a reactive mannose derivative to the peo chain end. the anionic polymerization of ethylene oxide was first initiated by potassium 2-dimethylaminoethanolate. the ring-opening polymerization of epsilon-caprolactone was then init ...200717705426
architecture of burkholderia cepacia complex sigma70 gene family: evidence of alternative primary and clade-specific factors, and genomic instability.the burkholderia cepacia complex (bcc) groups bacterial species with beneficial properties that can improve crop yields or remediate polluted sites but can also lead to dramatic human clinical outcomes among cystic fibrosis (cf) or immuno-compromised individuals. genome-wide regulatory processes of gene expression could explain parts of this bacterial duality. transcriptional sigma70 factors are components of these processes. they allow the reversible binding of the dna-dependent rna polymerase ...200717784948
multistate outbreak of burkholderia cenocepacia colonization and infection associated with the use of intrinsically contaminated alcohol-free mouthwash.no guidelines exist for the type of mouthwash that should be used in patients at increased risk for pneumonia. in 2005, we investigated a multistate outbreak of burkholderia cenocepacia associated with an intrinsically contaminated alcohol-free mouthwash (afm).200717925414
burkholderia cenocepacia c5424 produces a pigment with antioxidant properties using a homogentisate intermediate.burkholderia cenocepacia is a gram-negative opportunistic pathogen that belongs to the burkholderia cepacia complex. b. cenocepacia can survive intracellularly within phagocytic cells, and some epidemic strains produce a brown melanin-like pigment that can scavenge free radicals, resulting in the attenuation of the host cell oxidative burst. in this work, we demonstrate that the brown pigment produced by b. cenocepacia c5424 is synthesized from a homogentisate (hga) precursor. the disruption of ...200717933889
identification of putative noncoding rna genes in the burkholderia cenocepacia j2315 genome.noncoding rna (ncrna) genes are not involved in the production of mrna and proteins, but produce transcripts that function directly as structural or regulatory rnas. in the present study, the presence of ncrna genes in the genome of burkholderia cenocepacia j2315 was evaluated by combining comparative genomics (alignment-based) and predicted secondary structure approaches. two hundred and thirteen putative ncrna genes were identified in the b. cenocepacia j2315 genome and upregulated expression ...200717937666
bactericidal efficacy of liposomal aminoglycosides against burkholderia cenocepacia.burkholderia cenocepacia (formally a genotype of burkholderia cepacia complex called genomovar iii) has emerged as a serious opportunistic pathogen in individuals with cystic fibrosis. we developed a liposomal antibiotic formulation composed of 1,2-distearoyl-sn-glycero-3-phosphocholine and cholesterol (molar ratio 2:1) to overcome b. cenocepacia's resistance to commonly used aminoglycosidic antibiotics.200717673475
molecular typing and presence of genetic markers among strains of banana finger-tip rot pathogen, burkholderia cenocepacia, in taiwan.abstract burkholderia cenocepacia (genomovar iii of b. cepacia complex), the causal agent of banana finger-tip rot, is a common plant-associated bacterium but also an important opportunistic pathogen of humans. to better understand the nature of b. cenocepacia from banana, the genetic variation among b. cenocepacia isolates from various banana-growing regions in southern taiwan was examined. forty-four serial isolates recovered from diseased banana stigmata from three banana-growing regions duri ...200718944375
the complete structure and pro-inflammatory activity of the lipooligosaccharide of the highly epidemic and virulent gram-negative bacterium burkholderia cenocepacia et-12 (strain j2315).members of genus burkholderia include opportunistic gram-negative bacteria that are responsible for serious infections in immunocompromised and cystic fibrosis (cf) patients. the burkholderia cepacia complex is a group of microorganisms composed of at least nine closely related genomovars. among these, b. cenocepacia is widely recognized to cause epidemics associated with excessive mortality. species that belong to this strain are problematic cf pathogens because of their high resistance to anti ...200717219455
burkholderia cenocepacia requires a periplasmic htra protease for growth under thermal and osmotic stress and for survival in vivo.burkholderia cenocepacia, a member of the b. cepacia complex, is an opportunistic pathogen that causes serious infections in patients with cystic fibrosis. we identified a six-gene cluster in chromosome 1 encoding a two-component regulatory system (bcal2831 and bcal2830) and an htra protease (bcal2829) hypothesized to play a role in the b. cenocepacia stress response. reverse transcriptase pcr analysis of these six genes confirmed they are cotranscribed and comprise an operon. genes in this oper ...200717220310
diversity and distribution of burkholderia cepacia complex in the rhizosphere of rice and maize.a survey of burkholderia cepacia complex (bcc) species was conducted in agricultural fields within hangzhou, china. out of the 251 bacterial isolates recovered on the selective media from the rhizosphere of rice and maize, 112 of them were assigned to bcc by pcr assays. the species composition of the bcc isolates was analyzed by a combination of reca-restriction fragment length polymorphism assays, species-specific pcr tests and reca gene sequencing. the results revealed that the majority belong ...200717233735
characterization of sodc, a periplasmic superoxide dismutase from burkholderia cenocepacia.burkholderia cenocepacia is a gram-negative, non-spore-forming bacillus and a member of the burkholderia cepacia complex. b. cenocepacia can survive intracellularly in phagocytic cells and can produce at least one superoxide dismutase (sod). the inability of o2- to cross the cytoplasmic membrane, coupled with the periplasmic location of cu,znsods, suggests that periplasmic sods protect bacteria from superoxide that has an exogenous origin (for example, when cells are faced with reactive oxygen i ...200717325048
a putative gene cluster for aminoarabinose biosynthesis is essential for burkholderia cenocepacia viability.using a conditional mutagenesis strategy we demonstrate here that a gene cluster encoding putative aminoarabinose (ara4n) biosynthesis enzymes is essential for the viability of burkholderia cenocepacia. loss of viability is associated with dramatic changes in bacterial cell morphology and ultrastructure, increased permeability to propidium iodide, and sensitivity to sodium dodecyl sulfate, suggesting a general cell envelope defect caused by the lack of ara4n.200717337576
characterization of a bifunctional catalase-peroxidase of burkholderia cenocepacia.isolates of burkholderia cenocepacia express a putative haem-binding protein (molecular mass 97 kda) that displays intrinsic peroxidase activity. its role has been re-evaluated, and we now show that it is a bifunctional catalase-peroxidase, with activity against tetramethylbenzidine (tmb), o-dianisidine, pyrogallol, and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic) acid (abts). both peroxidase and catalase activities are optimal at ph 5.5-6.0. the gene encoding this enzyme was cloned and exp ...200717371508
infection with burkholderia cepacia complex bacteria and pulmonary exacerbations of cystic fibrosis.studies have shown that cystic fibrosis (cf) patients who are chronically infected with burkholderia cepacia complex bacteria may potentially acquire new strains of b cepacia. our objective was to determine whether pulmonary exacerbations of cf are associated with acquisition of new b cepacia strains or with b cepacia strain replacement.200717426227
bactericidal action of positive and negative ions in air.in recent years there has been renewed interest in the use of air ionisers to control of the spread of airborne infection. one characteristic of air ions which has been widely reported is their apparent biocidal action. however, whilst the body of evidence suggests a biocidal effect in the presence of air ions the physical and biological mechanisms involved remain unclear. in particular, it is not clear which of several possible mechanisms of electrical origin (i.e. the action of the ions, the p ...200717439657
high genotypic diversity of pseudomonas aeruginosa strains isolated from patients with cystic fibrosis in the czech republic.over the last decade, epidemic and frequently multidrug-resistant pseudomonas aeruginosa has increasingly been found among european cystic fibrosis (cf) patients. in the czech republic, more than half of the registered cf patients attend the prague cf centre. at this centre, a burkholderia cenocepacia strain was recently found to have spread among the patients. the aim of the present study was to assess whether p. aeruginosa isolates from patients at this centre were also genetically related and ...200717448645
comparative proteomic analysis of b. cenocepacia using two-dimensional liquid separations coupled with mass spectrometry.burkholderia cenocepacia is an important respiratory pathogen in persons with cystic fibrosis. we compared the proteomes of clinical and environmental isolates of b. cenocepacia by using a 2d liquid separation method coupled with mass spectrometry. proteome maps of four b. cenocepacia isolates were generated. in the first dimension, 5 mg of protein from each isolate was fractionated by chromatofocusing (cf) in the range of ph 4.0-7.0. in the second dimension, each cf fraction was separated by np ...200717499075
burkholderia cenocepacia, b. multivorans, b. ambifaria and b. vietnamiensis isolates from cystic fibrosis patients have different profiles of exoenzyme production.knowledge about the virulence mechanisms of species from the burkholderia cepacia complex (bcc) is still limited. the genomovar heterogeneity and production of different virulence factors are likely to contribute to the variation in the clinical outcome observed in bcc-infected cystic fibrosis (cf) patients. therefore, in this study we investigated the genetic polimorphism, the presence of genetic makers associated with virulence and transmissibility in bcc, and the profile of exoenzyme producti ...200717504297
pilus-mediated epithelial cell death in response to infection with burkholderia cenocepacia.burkholderia cenocepacia is an opportunistic pathogen that can cause serious infections in cystic fibrosis (cf) patients. the et12 lineage appears particularly virulent in cf; however, its pathogenesis is poorly understood and may be associated with host response. to help characterize this response, the ability of b. cenocepacia to induce cytotoxicity and apoptosis in an epithelial cell model was examined. upon infection with b. cenocepacia strain k56-2, a549 human lung epithelial cells underwen ...200717537663
the effect of recombinant human lactoferrin on growth and the antibiotic susceptibility of the cystic fibrosis pathogen burkholderia cepacia complex when cultured planktonically or as biofilms.the cystic fibrosis (cf) pathogen burkholderia cepacia complex (bcc) is innately resistant to antibiotics and the development of effective therapeutic strategies to treat these infections is a major challenge. the objectives of this study were to investigate the effects of recombinant human lactoferrin (rhl) on planktonic and biofilm cultures of bcc organisms and to establish whether lactoferrin alters the susceptibility of these cultures to a range of antibiotic therapies.200717595284
burkholderia cepacia complex infection in a cohort of italian patients with cystic fibrosis.the aims of this study were to detect burkholderia cepacia complex (bcc) strains in a cohort of cystic fibrosis patients (n=276) and to characterize bcc isolates by molecular techniques. the results showed that 11.23% of patients were infected by bcc. burkholderia cenocepacia lineage iii-a was the most prevalent species (64.3%) and, of these, 10% was cbla positive and 50% esmr positive. less than half of the strains were sensitive to ceftazidime, meropenem, piperacillin tazobactam, and trimethop ...200717618236
virulence of burkholderia cepacia complex strains in gp91phox-/- mice.in cystic fibrosis (cf), infection with burkholderia cepacia complex (bcc) strains may cause long-term asymptomatic airway colonization, or severe lung infection leading to rapid pulmonary decline. to assess the virulence of bcc strains, we established a lung infection model in mice with a null allele of the gene involved in x-linked chronic granulomatous disease (cgd). cgd mice, challenged intratracheally with 10(3) cells of the epidemic burkholderia cenocepacia strain j2315, died within 3 days ...200717627623
invasion and biofilm formation of burkholderia dolosa is comparable with burkholderia cenocepacia and burkholderia multivorans.colonisation with burkholderia cepacia complex pathogens has been associated with accelerated decline in cystic fibrosis (cf) patients. the two most common species among the cf community are burkholderia cenocepacia and burkholderia multivorans. however, burkholderia dolosa has recently been causing concern due to its transmissibility and virulence in cf patients.200716781896
exopolysaccharides produced by clinical strains belonging to the burkholderia cepacia complex.in the frame of a research line dedicated to better clarify the role of exopolysaccharides (eps) in bacterial virulence, eps produced by species of the burkholderia cepacia complex (bcc), namely burkholderia multivorans, burkholderia cenocepacia, and a bcc member of undetermined genomovar, all isolated at the cystic fibrosis regional centre of florence (italy), were investigated for they structural properties.200716860003
intracellular survival of burkholderia cenocepacia in macrophages is associated with a delay in the maturation of bacteria-containing vacuoles.strains of the burkholderia cepacia complex (bcc) are opportunistic bacteria that can cause life-threatening infections in patients with cystic fibrosis and chronic granulomatous disease. previous work has shown that bcc isolates can persist in membrane-bound vacuoles within amoeba and macrophages without bacterial replication, but the detailed mechanism of bacterial persistence is unknown. in this study, we have investigated the survival of the burkholderia cenocepacia strain j2315 within raw26 ...200716869828
regulation of sulfur assimilation pathways in burkholderia cenocepacia: identification of transcription factors cysb and ssur and their role in control of target genes.two genes encoding transcriptional regulators involved in sulfur assimilation pathways in burkholderia cenocepacia strain 715j have been identified and characterized functionally. knockout mutations in each of the b. cenocepacia genes were constructed and introduced into the genome of 715j by allelic replacement. studies on the utilization of various sulfur sources by 715j and the obtained mutants demonstrated that one of the b. cenocepacia regulators, designated cysb, is preferentially involved ...200716997956
highly purified lipopolysaccharides from burkholderia cepacia complex clinical isolates induce inflammatory cytokine responses via tlr4-mediated mapk signalling pathways and activation of nfkappab.in cystic fibrosis (cf), bacteria of the burkholderia cepacia complex (bcc) can induce a fulminant inflammation with pneumonitis and sepsis. lipopolysaccharide (lps) may be an important virulence factor associated with this decline but little is known about the molecular pathogenesis of bcc lps. in this study we have investigated the inflammatory response to highly purified lps from different bcc clinical isolates and the cellular signalling pathways employed. the inflammatory response (tnfalpha ...200717002785
identification of genes regulated by the cepir quorum-sensing system in burkholderia cenocepacia by high-throughput screening of a random promoter library.the burkholderia cenocepacia cepir quorum-sensing system regulates expression of extracellular proteases, chitinase, and genes involved in ornibactin biosynthesis, biofilm formation, and motility. in a genome-wide screen we identified cepir-regulated genes by screening a random promoter library of b. cenocepacia k56-2 constructed in a luminescence reporter detection plasmid for differential expression in response to n-octanoyl-l-homoserine lactone (ohl). eighty-nine clones were identified; in 58 ...200717122351
proteomic identification and characterization of bacterial factors associated with burkholderia cenocepacia survival in a murine host.burkholderia cenocepacia is a member of the burkholderia cepacia complex, a diverse family of gram-negative bacteria that are serious respiratory pathogens in immunocompromised patients and individuals with cystic fibrosis. to identify putative bacterial virulence determinants, proteomic profiles were compared between two b. cenocepacia isolates that demonstrated differential persistence in a mouse model of pulmonary infection; clinical isolate c1394 is rapidly cleared from the murine lung where ...200717185549
identification of potential cepr regulated genes using a cep box motif-based search of the burkholderia cenocepacia genome.the burkholderia cenocepacia cepir quorum sensing system has been shown to positively and negatively regulate genes involved in siderophore production, protease expression, motility, biofilm formation and virulence. in this study, two approaches were used to identify genes regulated by the cepir quorum sensing system. transposon mutagenesis was used to create lacz promoter fusions in a cepi mutant that were screened for differential expression in the presence of n-acylhomoserine lactones. a bioi ...200617187664
intracellular trafficking and replication of burkholderia cenocepacia in human cystic fibrosis airway epithelial cells.we investigated the trafficking of burkholderia cenocepacia, an opportunistic respiratory pathogen of persons with cystic fibrosis (cf), in immortalized cf airway epithelial cells in vitro. our results indicate that bacteria enter cells in a process involving actin rearrangement. whereas both live and heat-killed bacteria reside transiently in early endosomes, only live bacteria escape from late endosomes to colocalize in vesicles positive for lysosomal membrane marker lamp1, endoplasmic reticul ...200616922864
the mgtc gene of burkholderia cenocepacia is required for growth under magnesium limitation conditions and intracellular survival in macrophages.burkholderia cenocepacia, a bacterium commonly found in the environment, is an important opportunistic pathogen in patients with cystic fibrosis (cf). very little is known about the mechanisms by which b. cenocepacia causes disease, but chronic infection of the airways in cf patients may be associated, at least in part, with the ability of this bacterium to survive within epithelial cells and macrophages. survival in macrophages occurs in a membrane-bound compartment that is distinct from the ly ...200616988222
burkholderia cenocepacia zmpb is a broad-specificity zinc metalloprotease involved in virulence.in previous studies we characterized the burkholderia cenocepacia zmpa zinc metalloprotease. in this study, we determined that b. cenocepacia has an additional metalloprotease, which we designated zmpb. the zmpb gene is present in the same species as zmpa and was detected in b. cepacia, b. cenocepacia, b. stabilis, b. ambifaria, and b. pyrrocinia but was absent from b. multivorans, b. vietnamiensis, b. dolosa, and b. anthina. the zmpb gene was expressed, and zmpb was purified from escherichia co ...200616790782
identification of a response regulator gene for catabolite control from a pcb-degrading beta-proteobacteria, acidovorax sp. kks102.acidovorax sp. (formally pseudomonas sp.) strain kks102 carries a bph operon for the degradation of pcb/biphenyl. transcription from the pe promoter for the bph operon was found to be under catabolite control, i.e. the promoter activity was at a lower level when succinate, fumarate or acetate was added to the culture. some mutations in the immediate upstream region of the pe promoter resulted in catabolite-insensitive and constitutively low promoter activity, suggesting that a transcriptional ac ...200616796688
efflux pump genes of the resistance-nodulation-division family in burkholderia cenocepacia genome.burkholderia cenocepacia is recognized as opportunistic pathogen that can cause lung infections in cystic fibrosis patients. a hallmark of b. cenocepacia infections is the inability to eradicate the organism because of multiple intrinsic antibiotic resistance. as resistance-nodulation-division (rnd) efflux systems are responsible for much of the intrinsic multidrug resistance in gram-negative bacteria, this study aims to identify rnd genes in the b. cenocepacia genome and start to investigate th ...200616857052
a napkin-associated outbreak of burkholderia cenocepacia bacteraemia in haemodialysis patients.this article reports a catheter-related outbreak of bacteraemia involving 38 patients in two haemodialysis units in verona. burkholderia cepacia complex strains were isolated from human blood and from an individually wrapped disinfection napkin that was contained in a commercially available, sterile dressing kit used to handle central venous catheters. micro-organisms isolated from blood cultures and from the napkin were identified by standard procedures and confirmed as b. cenocepacia (genomova ...200616859809
computer-aided design of agents that inhibit the cep quorum-sensing system of burkholderia cenocepacia.recent research has provided evidence that interference with bacterial cell-to-cell signaling is a promising strategy for the development of novel antimicrobial agents. here we report on the computer-aided design of novel compounds that specifically inhibit an n-acyl-homoserine lactone-dependent communication system that is widespread among members of the genus burkholderia. this genus comprises more than 30 species, many of which are important pathogens of animals and humans. over the past few ...200616377703
distribution and genomic location of active insertion sequences in the burkholderia cepacia complex.this study aimed firstly to establish the distribution and copy number within the burkholderia cepacia complex of three insertion sequences (is402, is407 and is1416) that possess the ability to activate transcription and hence influence gene expression. a second aim was to map the genomic insertion sites of one of the active insertion sequences (is407) to establish putative links between insertion site and downstream gene activation. the resulting data revealed that all three insertion sequences ...200616388024
identification of an rtx determinant of burkholderia cenocepacia j2315 by subtractive hybridization.this study utilized suppressive subtractive hybridization between the clinical isolate burkholderia cenocepacia j2315 and the closely related environmental isolate burkholderia cepacia atcc 25416(t) to isolate dna fragments specific to b. cenocepacia j2315. analysis of the resulting pools of b. cenocepacia-specific dnas identified several fragments that may be part of putative virulence factors. further in silico analysis of a single fragment indicated that it was internal to a gene of which the ...200616388025
towards the proteome of burkholderia cenocepacia h111: setting up a 2-de reference map.polyphasic-taxonomic studies of the past decade have shown that the burkholderia cepacia complex (bcc) comprises at least nine species, which share a high degree of 16s rdna (98-100%) sequence similarity but only moderate levels of dna-dna hybridization. members of the bcc are well known as opportunistic pathogens of plants, animals and humans but also as biocontrol and bioremediation agents. in this study intra-, surface-associated and extracellular proteins of b. cenocepacia h111, which was is ...200616294309
exopolysaccharides from burkholderia cenocepacia inhibit neutrophil chemotaxis and scavenge reactive oxygen species.bacteria belonging to the burkholderia cepacia complex are important opportunistic pathogens in compromised hosts, particularly patients with cystic fibrosis or chronic granulomatous disease. isolates of b. cepacia complex may produce large amounts of exopolysaccharides (eps) that endow the bacteria with a mucoid phenotype and appear to facilitate bacterial persistence during infection. we showed that eps from a clinical b. cenocepacia isolate interfered with the function of human neutrophils in ...200616316987
parabs systems of the four replicons of burkholderia cenocepacia: new chromosome centromeres confer partition specificity.most bacterial chromosomes carry an analogue of the parabs systems that govern plasmid partition, but their role in chromosome partition is ambiguous. parabs systems might be particularly important for orderly segregation of multipartite genomes, where their role may thus be easier to evaluate. we have characterized parabs systems in burkholderia cenocepacia, whose genome comprises three chromosomes and one low-copy-number plasmid. a single parab locus and a set of parb-binding (pars) centromere ...200616452432
a complete lipopolysaccharide inner core oligosaccharide is required for resistance of burkholderia cenocepacia to antimicrobial peptides and bacterial survival in vivo.burkholderia cenocepacia is an important opportunistic pathogen of patients with cystic fibrosis. this bacterium is inherently resistant to a wide range of antimicrobial agents, including high concentrations of antimicrobial peptides. we hypothesized that the lipopolysaccharide (lps) of b. cenocepacia is important for both virulence and resistance to antimicrobial peptides. we identified hlda and hldd genes in b. cenocepacia strain k56-2. these two genes encode enzymes involved in the modificati ...200616513737
a comparison of alternative 60-mer probe designs in an in-situ synthesized oligonucleotide microarray.dna microarrays have proven powerful for functional genomics studies. several technologies exist for the generation of whole-genome arrays. it is well documented that 25mer probes directed against different regions of the same gene produce variable signal intensity values. however, the extent to which this is true for probes of greater length (60mers) is not well characterized. moreover, this information has not previously been reported for whole-genome arrays designed against bacteria, whose ge ...200616595014
identification of essential operons with a rhamnose-inducible promoter in burkholderia cenocepacia.scanning of bacterial genomes to identify essential genes is of biological interest, for understanding the basic functions required for life, and of practical interest, for the identification of novel targets for new antimicrobial therapies. in particular, the lack of efficacious antimicrobial treatments for infections caused by the burkholderia cepacia complex is causing high morbidity and mortality of cystic fibrosis patients and of patients with nosocomial infections. here, we present a metho ...200616597956
the ornibactin biosynthesis and transport genes of burkholderia cenocepacia are regulated by an extracytoplasmic function sigma factor which is a part of the fur regulon.burkholderia cenocepacia mutants that fail to produce the siderophore ornibactin were obtained following mutagenesis with mini-tn5tp. these mutants were shown to be growth restricted under conditions of iron depletion. in eight of the mutants, the transposon had integrated into one of two genes, orbi and orbj, encoding nonribosomal peptide synthetases. in the other mutant, the transposon had inserted into an open reading frame, orbs, located upstream from orbi. the polypeptide product of orbs ex ...200616672617
burkholderia cenocepacia utilizes ferritin as an iron source.burkholderia cenocepacia is a member of the burkholderia cepacia complex, a group of genetically similar species that inhabit a number of environmental niches, including the lungs of patients with cystic fibrosis (cf). to colonize the lung, this bacterium requires a source of iron to satisfy its nutritional requirements for this important metal. because of the high potential for damage in lung tissue resulting from oxygen-iron interactions, this metal is sequestered by a number of mechanisms tha ...200616687582
identification of burkholderia cepacia complex pathogens by rapid-cycle pcr with fluorescent hybridization probes.members of the burkholderia cepacia complex are important bacterial pathogens in cystic fibrosis (cf) patients. the b. cepacia complex currently consists of nine genetic subgroups (genomovars) of different epidemiological relevance and possibly of different pathogenic potential in humans. in this study, a new approach was developed for the rapid identification of b. cepacia genomovar i, burkholderia multivorans (genomovar ii), burkholderia cenocepacia (lineage iii-a and iii-b), burkholderia stab ...200616687590
effect of reduced ph on inorganic polyphosphate accumulation by burkholderia cepacia complex isolates.burkholderia cepacia complex (bcc) isolates causing pulmonary infection in cystic fibrosis (cf) patients grow within an acidic environment in the lung. as exposure to acid ph has been shown to increase intracellular inorganic polyphosphate (polyp) formation in some bacteria, we investigated the inter-relationship between acidic ph and polyp accumulation in bcc isolates.200616706902
use of ribosomal promoters from burkholderia cenocepacia and burkholderia cepacia for improved expression of transporter protein in escherichia coli.expression of heterologous protein in escherichia coli usually based on the iptg-inducible expression systems. the use of these systems for membrane protein production, however, usually caused cytotoxic problem that affected the yield and functional characterization of the protein. optimization of these systems for transporter protein production is time-consuming and is usually ineffective. here, we described the use of the ribosomal promoters p(s12) from burkholderia cenocepacia lmg16656 and fr ...200616737826
caenorhabditis elegans killing assay as an infection model to study the role of type iii secretion in burkholderia cenocepacia. 200616772429
distribution and expression of the zmpa metalloprotease in the burkholderia cepacia complex.the distribution of the metalloprotease gene zmpa was determined among strains of the burkholderia cepacia complex (bcc). the zmpa gene was present in b. cepacia, b. cenocepacia, b. stabilis, b. ambifaria and b. pyrrocinia but absent from b. multivorans, b. vietnamiensis, b. dolosa, and b. anthina. the presence of zmpa generally correlated with extracellular proteolytic activity with the exception of five strains, which had zmpa but had no detectable proteolytic activity when skim milk agar was ...200516321929
metabolic profiling of burkholderia cenocepacia, burkholderia ambifaria, and burkholderia pyrrocinia isolates from maize rhizosphere.burkholderia cenocepacia, burkholderia ambifaria, and burkholderia pyrrocinia are the burkholderia cepacia complex (bcc) species most frequently associated with roots of crop plants. to investigate the ecophysiological diversity of these species, metabolic profiling of maize rhizosphere isolates was carried out by means of the biolog system, using gn2 and sfn2 plates and different parameters related to optical density (od). the metabolic profiles produced by the sfn2 and gn2 plates were identica ...200516328653
effect of cystic fibrosis exacerbations on neutrophil function.in cystic fibrosis (cf), inflammation is caused by persistent bacterial infection from pseudomonas aeruginosa and burkholderia cenocepacia in the lung and is characterised by the persistent infiltration of massive numbers of neutrophils which leads to lung injury. the aim of this present study was to investigate the effects of cf exacerbations on the reactivity of peripheral blood neutrophils compared to data from a normal healthy control population. peripheral blood neutrophils were isolated fr ...200515683855
reconstitution of o-specific lipopolysaccharide expression in burkholderia cenocepacia strain j2315, which is associated with transmissible infections in patients with cystic fibrosis.burkholderia cenocepacia is an opportunistic bacterium that infects patients with cystic fibrosis. b. cenocepacia strains j2315, k56-2, c5424, and bc7 belong to the et12 epidemic clone, which is transmissible among patients. we have previously shown that transposon mutants with insertions within the o antigen cluster of strain k56-2 are attenuated for survival in a rat model of lung infection. from the genomic dna sequence of the o antigen-deficient strain j2315, we have identified an o antigen ...200515687196
down-regulation of il-8 expression in human airway epithelial cells through helper-dependent adenoviral-mediated rna interference.interleukin (il)-8 is a potent neutrophil chemotactic factor and a crucial mediator in neutrophil-dependent inflammation. various cell types produce il-8, either in response to external stimuli such as cytokines or bacterial infection, or after malignant transformation. anti-il-8 strategies have been considered for anti-inflammatory therapy. in this paper we demonstrate that the rna interference technique can be used to efficiently down-regulate il-8 protein expression in airway epithelial cells ...200515740640
infection-induced kinin b1 receptors in human pulmonary fibroblasts: role of intact pathogens and p38 mitogen-activated protein kinase-dependent signaling.kinin b(1) receptors (b(1)r) are involved in many pathophysiological processes, and its expression is up-regulated in inflammatory pulmonary disease. although bacteria can generate kinin peptides, the molecular signaling mechanisms regulating b(1)r during infection by intact pathogens is unknown. the serious opportunistic clinical isolate burkholderia cenocepacia (b. cen.) belongs to the important b. cepacia complex (bcc) of gram-negative pathogens that rapidly causes fatal pulmonary disease in ...200515743925
burkholderia cenocepacia induces neutrophil necrosis in chronic granulomatous disease.burkholderia cepacia complex is a life-threatening group of pathogens for patients with chronic granulomatous disease (cgd), whose phagocytes are unable to produce reactive oxygen species (ros). unlike other cgd pathogens, b. cepacia complex is particularly virulent, characteristically causing septicemia, and is the bacterial species responsible for most fatalities in these patients. we found that a nonmucoid burkholderia cenocepacia (a predominant species in the b. cepacia complex) isolate was ...200515749893
genotypic characterization of burkholderia cenocepacia strains by rep-pcr and pcr-rflp of the flic gene.thirty-five strains of burkholderia cenocepacia from clinical and environmental sources were characterized genotypically by repetitive sequence pcr (eric- and box-pcr) and polymerase chain reaction-restriction fragment length polymorphism (pcr-rflp) analysis of the flagellin gene (flic). in cluster analysis based on the repetitive pcr profiles the strains were composed of five clusters, of which clusters 1, 2 and 3 were more closely related to each other than to clusters 4 and 5. it has been rep ...200515796974
conservation of a novel protein associated with an antibiotic efflux operon in burkholderia cenocepacia.burkholderia cenocepacia is a significant problem in individuals with cystic fibrosis and is a member of the b. cepacia complex of closely related antibiotic resistant bacteria. a salicylate-regulated antibiotic efflux operon has been identified in b. cenocepacia and one of its four genes, llpe, is without parallel in previously reported efflux operons. pcr amplification and sequencing of llpe from b. cepacia complex isolates demonstrated the highest prevalence in b. cenocepacia with a high degr ...200515837391
an expression vector containing a rhamnose-inducible promoter provides tightly regulated gene expression in burkholderia cenocepacia.infection of the respiratory tract caused by burkholderia cepacia complex poses a serious risk for cystic fibrosis (cf) patients due to the high morbidity and mortality associated with the chronic infection and the lack of efficacious antimicrobial treatments. a detailed understanding of the pathogenicity of b. cepacia complex infections is hampered in part by the limited availability of genetic tools and the inherent resistance of these isolates to the most common antibiotics used for genetic s ...200515925406
a minor catalase/peroxidase from burkholderia cenocepacia is required for normal aconitase activity.the opportunistic bacterium burkholderia cenocepacia c5424 contains two catalase/peroxidase genes, kata and katb. to investigate the functions of these genes, kata and katb mutants were generated by targeted integration of suicide plasmids into the kata and katb genes. the catalase/peroxidase activity of the kata mutant was not affected as compared with that of the parental strain, while no catalase/peroxidase activity was detected in the katb mutant. however, the kata mutant displayed reduced r ...200515942004
widespread clone of burkholderia cenocepacia in cystic fibrosis patients in the czech republic.the morbidity and mortality rates in patients with cystic fibrosis (cf) are significantly affected by infections with burkholderia cepacia complex. in a czech cf centre, the prevalence of the infection reached up to 30 %, with the majority of patients found to be infected with burkholderia cenocepacia (formerly genomovar iii of the burkholderia cepacia complex). since b. cenocepacia is associated with patient-to-patient transmission and epidemic outbreaks among cf patients, this study sought to ...200515947430
functional analysis of the burkholderia cenocepacia zmpa metalloprotease.burkholderia cenocepacia zmpa is expressed as a preproenzyme typical of thermolysin-like proteases such as pseudomonas aeruginosa lasb and bacillus thermoproteolyticus thermolysin. the zmpa gene was expressed using the ppro-exhta his(6) tag expression system, which incorporates a six-his tag at the n-terminal end of the protein, and recombinant zmpa was purified using ni-nitrilotriacetic acid affinity chromatography. upon refolding of the recombinant his(6)-pre-pro-zmpa (62 kda), the fusion prot ...200515968051
direct binding of the quorum sensing regulator cepr of burkholderia cenocepacia to two target promoters in vitro.burkholderia cenocepacia is an opportunistic human pathogen that can aggressively colonize the cystic fibrosis lung. this organism has a luxr/luxi-type quorum sensing system that enables cell-cell communication via exchange of acyl homoserine lactones (ahls). the cepr and cepi proteins constitute a global regulatory system, controlling expression of at least 40 genes, including those controlling swarming motility and biofilm formation. in this study, we isolated seven lacz fusions in a clinical ...200515978077
functional and topological analysis of the burkholderia cenocepacia priming glucosyltransferase bceb, involved in the biosynthesis of the cepacian exopolysaccharide.the bceb protein of the cystic fibrosis mucoid isolate burkholderia cenocepacia ist432 is proposed to catalyze the first step of the exopolysaccharide repeat unit assembly. extracts of escherichia coli cells overexpressing bceb were shown to contain glycosyltransferase activity and mediate incorporation of glucose-1-phosphate into membrane lipids. the amino acid sequence of bceb exhibits two conserved regions, one comprising two invariant aspartic acid residues (asp339 and asp355) that are essen ...200515995219
temperate bacteriophages dk4 and bcepmu from burkholderia cenocepacia j2315 are identical. 200516009540
use of suppression-subtractive hybridization to identify genes in the burkholderia cepacia complex that are unique to burkholderia cenocepacia.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- ...200516030222
characterization of the cciir quorum-sensing system in burkholderia cenocepacia.several transmissible burkholderia cenocepacia strains that infect multiple cystic fibrosis patients contain a genomic island designated as the cenocepacia island (cci). the cci contains a predicted n-acylhomoserine lactone (ahl) synthase gene, ccii, and a predicted response regulator gene, ccir. ahl production profiles indicated that ccii catalyzes the synthesis of n-hexanoyl-l-homoserine lactone and minor amounts of n-octanoyl-l-homoserine lactone. the ccii and ccir genes were found to be cotr ...200516041013
in vitro evaluation of efficacy of 5 methods of disinfection on mouthpieces and facemasks contaminated by strains of cystic fibrosis patients.home-nebulizers are a potential source of bacterial infection of the respiratory tract in patients suffering from cystic fibrosis. recommendations for disinfecting this equipment are often arbitrary and sometimes contradictory.200516046195
neutrophil cell death, activation and bacterial infection in cystic fibrosis.cystic fibrosis (cf) is characterised by chronic endobronchial bacterial infection and neutrophil mediated inflammation. neutrophil apoptosis is essential for the resolution of inflammation. this study assessed the relationship between levels of neutrophil apoptosis and sputum microbiology in matched clinically stable patients with cf.200516061707
effect of fusarium verticillioides on maize-root-associated burkholderia cenocepacia populations.burkholderia cepacia complex (bcc) bacteria are naturally present in the rhizosphere of several crop plants and have been found to antagonize a wide range of important plant pathogens. in this study, we evaluated the effect of the pathogenic fungus fusarium verticillioides on bcc populations recovered from the roots of zea mays plants. maize plants were cultivated under greenhouse conditions and bacterial colonies were randomly isolated from distinct root portions of fusarium-treated and control ...200516085398
cable pili and the 22-kilodalton adhesin are required for burkholderia cenocepacia binding to and transmigration across the squamous epithelium.burkholderia cenocepacia strains expressing both cable (cbl) pili and the 22-kda adhesin bind to cytokeratin 13 (ck13) strongly and invade squamous epithelium efficiently. it has not been established, however, whether the gene encoding the adhesin is located in the cbl operon or what specific contribution the adhesin and cbl pili lend to binding and transmigration or invasion capacity of b. cenocepacia. by immunoscreening an expression library of b. cenocepacia isolate bc7, we identified a large ...200516113259
quorum-sensing mutations affect attachment and stability of burkholderia cenocepacia biofilms.biofilm formation in burkholderia cenocepacia has been shown to rely in part on acylhomoserine lactone-based quorum sensing. for many other bacterial species, it appears that both the initial adherence and the later stages of biofilm maturation are affected when quorum sensing pathways are inhibited. in this study, we examined the effects of mutations in the cepir and cciir quorum-sensing systems of burkholderia cenocepacia k56-2 with respect to biofilm attachment and antibiotic resistance. we a ...200516151106
class 2 integron with a novel cassette array in a burkholderia cenocepacia isolate. 200516189138
transmission of burkholderia cepacia complex: evidence for new epidemic clones infecting cystic fibrosis patients in italy.to analyze national prevalence, genomovar distribution, and epidemiology of the burkholderia cepacia complex in italy, 225 putative b. cepacia complex isolates were obtained from 225 cystic fibrosis (cf) patients attending 18 cf centers. the genomovar status of these isolates was determined by a polyphasic approach, which included whole-cell protein electrophoresis and reca restriction fragment length polymorphism (rflp) analysis. two approaches were used to genotype b. cepacia complex isolates: ...200516207975
update on the burkholderia cepacia complex.the burkholderia cepacia complex is comprised of a group of related bacterial species that are capable of causing life-threatening respiratory tract infection in persons with cystic fibrosis. this article reviews advances in our understanding of burkholderia cepacia complex infection in cystic fibrosis, focusing on the taxonomy, clinical microbiology, and epidemiology, as well as the natural history and clinical outcomes associated with burkholderia cepacia complex infection.200516217180
detection of cultured and uncultured burkholderia cepacia complex bacteria naturally occurring in the maize rhizosphere.the species composition of a burkholderia cepacia complex population naturally occurring in the maize rhizosphere was investigated by using both culture-dependent and culture-independent methods. b. cepacia complex isolates were recovered from maize root slurry on the two selective media pseudomonas cepacia azelaic acid tryptamine (pcat) and trypan blue tetracycline (tb-t) and subjected to identification by a combination of restriction fragment length polymorphism (rflp) analysis and species-spe ...200516232288
disruption of tight junctions during traversal of the respiratory epithelium by burkholderia cenocepacia.burkholderia cenocepacia is an opportunistic bacterial species capable of causing life-threatening respiratory tract infection in persons with cystic fibrosis (cf). unlike most other pathogens in cf, which typically remain confined to the endobronchial spaces, b. cenocepacia can traverse airway epithelium to cause bacteremia and sepsis. the mechanisms by which this occurs, however, are unknown. we examined the transmigration of b. cenocepacia through polarized respiratory epithelium. representat ...200516239504
transient isolation of burkholderia multivorans and burkholderia cenocepacia from a brazilian cystic fibrosis patient chronically colonized with burkholderia vietnamiensis.fifteen serial burkholderia cepacia complex isolates recovered over a period of 4 years from a single cystic fibrosis patient were analysed for genomovar status by means of reca sequence determination, and genetic relatedness by rapd-pcr. twelve isolates were assigned as burkholderia vietnamiensis, two as burkholderia cenocepacia and one as burkholderia multivorans. b. vietnamiensis persisted in the airways during 4 years, except in three occasions when b. cenocepacia or b. multivorans were isol ...200516266831
iron availability influences aggregation, biofilm, adhesion and invasion of pseudomonas aeruginosa and burkholderia cenocepacia.pseudomonas aeruginosa and burkholderia cenocepacia are predominant opportunistic pathogens in cystic fibrosis (cf) patients. in healthy humans the lower respiratory tract as well as all mucosa, contains a very low free iron concentration (10(-18) m), while in cf patients sputum iron concentration is very high, showing a median value of 63x10(-6) m. accumulation of catalytic reactive iron heavily contributes to subsequent clinical complications in the lung disorders by the production of reactive ...200516388713
isolation and characterization of burkholderia cenocepacia mutants deficient in pyochelin production: pyochelin biosynthesis is sensitive to sulfur availability.the opportunistic pathogen burkholderia cenocepacia produces the yellow-green fluorescent siderophore, pyochelin. to isolate mutants which do not produce this siderophore, we mutagenized b. cenocepacia with the transposon mini-tn5tp. two nonfluorescent mutants were identified which were unable to produce pyochelin. in both mutants, the transposon had integrated into a gene encoding an orthologue of cysw, a component of the sulfate/thiosulfate transporter. the cysw gene was located within a putat ...200414702294
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