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Evolution of Quorum Sensing in Pseudomonas aeruginosa Can Occur via Loss of Function and Regulon Modulation. mSystems 2022; 7:e0035422. [PMID: 36190124 PMCID: PMC9600717 DOI: 10.1128/msystems.00354-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Pseudomonas aeruginosa populations evolving in cystic fibrosis lungs, animal hosts, natural environments and in vitro undergo extensive genetic adaption and diversification. A common mutational target is the quorum sensing (QS) system, a three-unit regulatory system that controls the expression of virulence factors and secreted public goods. Three evolutionary scenarios have been advocated to explain selection for QS mutants: (i) disuse of the regulon, (ii) cheating through the exploitation of public goods, or (ii) modulation of the QS regulon. Here, we examine these scenarios by studying a set of 61 QS mutants from an experimental evolution study. We observed nonsynonymous mutations in all three QS systems: Las, Rhl, and Pseudomonas Quinolone Signal (PQS). The majority of the Las mutants had large deletions of the Las regulon, resulting in loss of QS function and the inability to produce QS-regulated traits, thus supporting the first or second scenarios. Conversely, phenotypic and gene expression analyses of Rhl mutants support network modulation (third scenario), as these mutants overexpressed the Las and Rhl receptors and showed an altered QS-regulated trait production profile. PQS mutants also showed patterns of regulon modulation leading to strain diversification and phenotypic tradeoffs, where the upregulation of certain QS traits is associated with the downregulation of others. Overall, our results indicate that mutations in the different QS systems lead to diverging effects on the QS trait profile in P. aeruginosa populations. These mutations might not only affect the plasticity and diversity of evolved populations but could also impact bacterial fitness and virulence in infections. IMPORTANCE Pseudomonas aeruginosa uses quorum sensing (QS), a three-unit multilayered network, to coordinate expression of traits required for growth and virulence in the context of infections. Despite its importance for bacterial fitness, the QS regulon appears to be a common mutational target during long-term adaptation of P. aeruginosa in the host, natural environments, and experimental evolutions. This raises questions of why such an important regulatory system is under selection and how mutations change the profile of QS-regulated traits. Here, we examine a set of 61 experimentally evolved QS mutants to address these questions. We found that mutations involving the master regulator, LasR, resulted in an almost complete breakdown of QS, while mutations in RhlR and PqsR resulted in modulations of the regulon, where both the regulon structure and the QS-regulated trait profile changed. Our work reveals that natural selection drives diversification in QS activity patterns in evolving populations.
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Gunardi WD, Timotius KH, Natasha A, Evriarti PR. Biofilm Targeting Strategy in the Eradication of Burkholderia Infections: A Mini-Review. Open Microbiol J 2021. [DOI: 10.2174/1874285802115010051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Burkholderia are intracellular pathogenic bacteria which can produce biofilm. This biofilm protects the intracellular pathogenic bacteria from antibiotic treatment and the immunological system of the host. Therefore, this review aims to describe the capacity of Burkholderia to form a biofilm, the regulation of its biofilm formation, the efficacy of antibiotics to eradicate biofilm, and the novel therapy which targets its biofilm. Burkholderia's biofilm is characterized by its lipopolysaccharides, exopolysaccharides (EPSs), biofilm-associated proteins, and eDNA. Its regulation is made by quorum sensing, c-di-AMP, sRNA, and two component systems. Many antibiotics have been used as sole or mixture agents; however, they are not always effective in eradicating the biofilm-forming Burkholderia. Inhibitors of quorum sensing and other non-conventional antibiotic approaches are promising to discover effective treatment of Burkholderia infections.
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An investigation of Burkholderia cepacia complex methylomes via SMRT sequencing and mutant analysis. J Bacteriol 2021; 203:e0068320. [PMID: 33753468 DOI: 10.1128/jb.00683-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Bacterial genomes can be methylated at particular motifs by methyltransferases (M). This DNA modification allows restriction endonucleases (R) to discriminate between self and foreign DNA. While the accepted primary function of such restriction modification (RM) systems is to degrade incoming foreign DNA, other roles of RM systems and lone R or M components have been found in genome protection, stability and the regulation of various phenotypes. The Burkholderia cepacia complex (Bcc) is a group of closely related opportunistic pathogens with biotechnological potential. Here, we constructed and analysed mutants lacking various RM components in the clinical Bcc isolate Burkholderia cenocepacia H111 and used SMRT sequencing of single mutants to assign the B. cenocepacia H111 Ms to their cognate motifs. DNA methylation is shown to affect biofilm formation, cell shape, motility, siderophore production and membrane vesicle production. Moreover, DNA methylation had a large effect on the maintenance of the Bcc virulence megaplasmid pC3. Our data also suggest that the gp51 M-encoding gene, which is essential in H111 and is located within a prophage, is required for maintaining the bacteriophage in a lysogenic state, thereby ensuring a constant, low level of phage production within the bacterial population.ImportanceWhile genome sequence determines an organism's proteins, methylation of the nucleotides themselves can confer additional properties. In bacteria, Ms modify specific nucleotide motifs to allow discrimination of 'self' from 'non-self' DNA, e.g. from bacteriophages. Restriction enzymes detect 'non-self' methylation patterns and cut foreign DNA. Furthermore, methylation of promoter regions can influence gene expression and hence affect various phenotypes. In this study, we determined the methylated motifs of four strains from the Burkholderia cepacia complex of opportunistic pathogens. We deleted all genes encoding the restriction and modification components in one of these strains, Burkholderia cenocepacia H111. It is shown that DNA methylation affects various phenotypic traits, the most noteworthy being lysogenicity of a bacteriophage and maintenance of a virulence megaplasmid.
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Mapping of the Denitrification Pathway in Burkholderia thailandensis by Genome-Wide Mutant Profiling. J Bacteriol 2020; 202:JB.00304-20. [PMID: 32900830 DOI: 10.1128/jb.00304-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 08/28/2020] [Indexed: 12/11/2022] Open
Abstract
Burkholderia thailandensis is a soil saprophyte that is closely related to the pathogen Burkholderia pseudomallei, the etiological agent of melioidosis in humans. The environmental niches and infection sites occupied by these bacteria are thought to contain only limited concentrations of oxygen, where they can generate energy via denitrification. However, knowledge of the underlying molecular basis of the denitrification pathway in these bacteria is scarce. In this study, we employed a transposon sequencing (Tn-Seq) approach to identify genes conferring a fitness benefit for anaerobic growth of B. thailandensis Of the 180 determinants identified, several genes were shown to be required for growth under denitrifying conditions: the nitrate reductase operon narIJHGK2K1, the aniA gene encoding a previously unknown nitrite reductase, and the petABC genes encoding a cytochrome bc 1, as well as three novel regulators that control denitrification. Our Tn-Seq data allowed us to reconstruct the entire denitrification pathway of B. thailandensis and shed light on its regulation. Analyses of growth behaviors combined with measurements of denitrification metabolites of various mutants revealed that nitrate reduction provides sufficient energy for anaerobic growth, an important finding in light of the fact that some pathogenic Burkholderia species can use nitrate as a terminal electron acceptor but are unable to complete denitrification. Finally, we demonstrated that a nitrous oxide reductase mutant is not affected for anaerobic growth but is defective in biofilm formation and accumulates N2O, which may play a role in the dispersal of B. thailandensis biofilms.IMPORTANCE Burkholderia thailandensis is a soil-dwelling saprophyte that is often used as surrogate of the closely related pathogen Burkholderia pseudomallei, the causative agent of melioidosis and a classified biowarfare agent. Both organisms are adapted to grow under oxygen-limited conditions in rice fields by generating energy through denitrification. Microoxic growth of B. pseudomallei is also considered essential for human infections. Here, we have used a Tn-Seq approach to identify the genes encoding the enzymes and regulators required for growth under denitrifying conditions. We show that a mutant that is defective in the conversion of N2O to N2, the last step in the denitrification process, is unaffected in microoxic growth but is severely impaired in biofilm formation, suggesting that N2O may play a role in biofilm dispersal. Our study identified novel targets for the development of therapeutic agents to treat meliodiosis.
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Kramer J, López Carrasco MÁ, Kümmerli R. Positive linkage between bacterial social traits reveals that homogeneous rather than specialised behavioral repertoires prevail in natural Pseudomonas communities. FEMS Microbiol Ecol 2020; 96:5643885. [PMID: 31769782 DOI: 10.1093/femsec/fiz185] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 11/22/2019] [Indexed: 12/27/2022] Open
Abstract
Bacteria frequently cooperate by sharing secreted metabolites such as enzymes and siderophores. The expression of such 'public good' traits can be interdependent, and studies on laboratory systems have shown that trait linkage affects eco-evolutionary dynamics within bacterial communities. Here, we examine whether linkage among social traits occurs in natural habitats by examining investment levels and correlations between five public goods (biosurfactants, biofilm components, proteases, pyoverdines and toxic compounds) in 315 Pseudomonas isolates from soil and freshwater communities. Our phenotypic assays revealed that (i) social trait expression profiles varied dramatically; (ii) correlations between traits were frequent, exclusively positive and sometimes habitat-specific; and (iii) heterogeneous (specialised) trait repertoires were rarer than homogeneous (unspecialised) repertoires. Our results show that most isolates lie on a continuum between a 'social' type producing multiple public goods, and an 'asocial' type showing low investment into social traits. This segregation could reflect local adaptation to different microhabitats, or emerge from interactions between different social strategies. In the latter case, our findings suggest that the scope for competition among unspecialised isolates exceeds the scope for mutualistic exchange of different public goods between specialised isolates. Overall, our results indicate that complex interdependencies among social traits shape microbial lifestyles in nature.
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Affiliation(s)
- Jos Kramer
- Department of Plant and Microbial Biology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.,Department of Quantitative Biomedicine, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Miguel Ángel López Carrasco
- Department of Plant and Microbial Biology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.,Departamento de Biología Celular, Genética y Fisiología, University of Málaga, Bulevar Louis Pasteur 31, 29010 Málaga, Spain
| | - Rolf Kümmerli
- Department of Plant and Microbial Biology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.,Department of Quantitative Biomedicine, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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Oppy CC, Jebeli L, Kuba M, Oates CV, Strugnell R, Edgington-Mitchell LE, Valvano MA, Hartland EL, Newton HJ, Scott NE. Loss of O-Linked Protein Glycosylation in Burkholderia cenocepacia Impairs Biofilm Formation and Siderophore Activity and Alters Transcriptional Regulators. mSphere 2019; 4:e00660-19. [PMID: 31722994 PMCID: PMC6854043 DOI: 10.1128/msphere.00660-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 10/24/2019] [Indexed: 02/07/2023] Open
Abstract
O-linked protein glycosylation is a conserved feature of the Burkholderia genus. The addition of the trisaccharide β-Gal-(1,3)-α-GalNAc-(1,3)-β-GalNAc to membrane exported proteins in Burkholderia cenocepacia is required for bacterial fitness and resistance to environmental stress. However, the underlying causes of the defects observed in the absence of glycosylation are unclear. Using proteomics, luciferase reporter assays, and DNA cross-linking, we demonstrate the loss of glycosylation leads to changes in transcriptional regulation of multiple proteins, including the repression of the master quorum CepR/I. These proteomic and transcriptional alterations lead to the abolition of biofilm formation and defects in siderophore activity. Surprisingly, the abundance of most of the known glycosylated proteins did not significantly change in the glycosylation-defective mutants, except for BCAL1086 and BCAL2974, which were found in reduced amounts, suggesting they could be degraded. However, the loss of these two proteins was not responsible for driving the proteomic alterations, biofilm formation, or siderophore activity. Together, our results show that loss of glycosylation in B. cenocepacia results in a global cell reprogramming via alteration of the transcriptional regulatory systems, which cannot be explained by the abundance changes in known B. cenocepacia glycoproteins.IMPORTANCE Protein glycosylation is increasingly recognized as a common posttranslational protein modification in bacterial species. Despite this commonality, our understanding of the role of most glycosylation systems in bacterial physiology and pathogenesis is incomplete. In this work, we investigated the effect of the disruption of O-linked glycosylation in the opportunistic pathogen Burkholderia cenocepacia using a combination of proteomic, molecular, and phenotypic assays. We find that in contrast to recent findings on the N-linked glycosylation systems of Campylobacter jejuni, O-linked glycosylation does not appear to play a role in proteome stabilization of most glycoproteins. Our results reveal that loss of glycosylation in B. cenocepacia strains leads to global proteome and transcriptional changes, including the repression of the quorum-sensing regulator cepR (BCAM1868) gene. These alterations lead to dramatic phenotypic changes in glycosylation-null strains, which are paralleled by both global proteomic and transcriptional alterations, which do not appear to directly result from the loss of glycosylation per se. This research unravels the pleiotropic effects of O-linked glycosylation in B. cenocepacia, demonstrating that its loss does not simply affect the stability of the glycoproteome, but also interferes with transcription and the broader proteome.
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Affiliation(s)
- Cameron C Oppy
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Australia
| | - Leila Jebeli
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Miku Kuba
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Clare V Oates
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Richard Strugnell
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Laura E Edgington-Mitchell
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria, Australia
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- Department of Oral and Maxillofacial Surgery, New York University College of Dentistry, Bluestone Center for Clinical Research, New York, New York, USA
| | - Miguel A Valvano
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
- Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Elizabeth L Hartland
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Molecular and Translational Science, Monash University, Clayton, Victoria, Australia
| | - Hayley J Newton
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
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Granato ET, Ziegenhain C, Marvig RL, Kümmerli R. Low spatial structure and selection against secreted virulence factors attenuates pathogenicity in Pseudomonas aeruginosa. ISME JOURNAL 2018; 12:2907-2918. [PMID: 30065310 DOI: 10.1038/s41396-018-0231-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 06/14/2018] [Accepted: 06/19/2018] [Indexed: 02/01/2023]
Abstract
Bacterial opportunistic pathogens are feared for their difficult-to-treat nosocomial infections and for causing morbidity in immunocompromised patients. Here, we study how such a versatile opportunist, Pseudomonas aeruginosa, adapts to conditions inside and outside its model host Caenorhabditis elegans, and use phenotypic and genotypic screens to identify the mechanistic basis of virulence evolution. We found that virulence significantly dropped in unstructured environments both in the presence and absence of the host, but remained unchanged in spatially structured environments. Reduction of virulence was either driven by a substantial decline in the production of siderophores (in treatments without hosts) or toxins and proteases (in treatments with hosts). Whole-genome sequencing of evolved clones revealed positive selection and parallel evolution across replicates, and showed an accumulation of mutations in regulator genes controlling virulence factor expression. Our study identifies the spatial structure of the non-host environment as a key driver of virulence evolution in an opportunistic pathogen.
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Affiliation(s)
- Elisa T Granato
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland. .,Department of Zoology, University of Oxford, Oxford, United Kingdom.
| | - Christoph Ziegenhain
- Department Biology II, Ludwig-Maximilians-University, Munich, Germany.,Department of Cell and Molecular Biology, Karolinska Institutet, Solna, Sweden
| | - Rasmus L Marvig
- Center for Genomic Medicine, Rigshospitalet, Copenhagen, Denmark
| | - Rolf Kümmerli
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
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Burkholderia pseudomallei Biofilm Promotes Adhesion, Internalization and Stimulates Proinflammatory Cytokines in Human Epithelial A549 Cells. PLoS One 2016; 11:e0160741. [PMID: 27529172 PMCID: PMC4987058 DOI: 10.1371/journal.pone.0160741] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 07/25/2016] [Indexed: 11/19/2022] Open
Abstract
Burkholderia pseudomallei is a Gram-negative bacterium that causes melioidosis. Inhalational exposure leading to pulmonary melioidosis is the most common clinical manifestation with significant mortality. However, the role of B. pseudomallei biofilm phenotype during bacterial-host interaction remains unclear. We hypothesize that biofilm phenotype may play a role in such interactions. In this study, B. pseudomallei H777 (biofilm wild type), B. pseudomallei M10 (biofilm mutant) and B. pseudomallei C17 (biofilm-complemented) strains were used to assess the contribution of biofilm to adhesion to human lung epithelial cells (A549), intracellular interactions, apoptosis/necrosis and impact on proinflammatory responses. Confocal laser scanning microscopy demonstrated that B. pseudomallei H777 and C17 produced biofilm, whereas M10 did not. To determine the role of biofilm in host interaction, we assessed the ability of each of the three strains to interact with the A549 cells at MOI 10. Strain H777 exhibited higher levels of attachment and invasion compared to strain M10 (p < 0.05). In addition, the biofilm-complemented strain, C17 exhibited restored bacterial invasion ability. Flow cytometry combined with a double-staining assay using annexin V and propidium iodide revealed significantly higher numbers of early apoptotic and late apoptotic A549 cells when these were infected with strain H777 (1.52%) and C17 (1.43%) compared to strain M10 (0.85%) (p < 0.05). Strains H777 and C17 were able to stimulate significant secretion of IL-6 and IL-8 compared with the biofilm mutant (p < 0.05). Together, these findings demonstrated the role of biofilm-associated phenotypes of B. pseudomallei in cellular pathogenesis of human lung epithelial cells with respect to initial attachment and invasion, apoptosis and proinflammatory responses.
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Oliveira NM, Martinez-Garcia E, Xavier J, Durham WM, Kolter R, Kim W, Foster KR. Biofilm Formation As a Response to Ecological Competition. PLoS Biol 2015; 13:e1002191. [PMID: 26158271 PMCID: PMC4497666 DOI: 10.1371/journal.pbio.1002191] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 05/29/2015] [Indexed: 12/28/2022] Open
Abstract
Bacteria form dense surface-associated communities known as biofilms that are central to their persistence and how they affect us. Biofilm formation is commonly viewed as a cooperative enterprise, where strains and species work together for a common goal. Here we explore an alternative model: biofilm formation is a response to ecological competition. We co-cultured a diverse collection of natural isolates of the opportunistic pathogen Pseudomonas aeruginosa and studied the effect on biofilm formation. We show that strain mixing reliably increases biofilm formation compared to unmixed conditions. Importantly, strain mixing leads to strong competition: one strain dominates and largely excludes the other from the biofilm. Furthermore, we show that pyocins, narrow-spectrum antibiotics made by other P. aeruginosa strains, can stimulate biofilm formation by increasing the attachment of cells. Side-by-side comparisons using microfluidic assays suggest that the increase in biofilm occurs due to a general response to cellular damage: a comparable biofilm response occurs for pyocins that disrupt membranes as for commercial antibiotics that damage DNA, inhibit protein synthesis or transcription. Our data show that bacteria increase biofilm formation in response to ecological competition that is detected by antibiotic stress. This is inconsistent with the idea that sub-lethal concentrations of antibiotics are cooperative signals that coordinate microbial communities, as is often concluded. Instead, our work is consistent with competition sensing where low-levels of antibiotics are used to detect and respond to the competing genotypes that produce them. Mixing natural isolates of the pathogenic bacterium Pseudomonas aeruginosa shows that the formation of biofilm is a response to antibiotic stress from competing genotypes. Bacteria often attach to each other and to surfaces and make biofilms. These dense communities occur everywhere, including on us and inside us, where they are central to both health and disease. Biofilm formation is often viewed as the coordinated action of multiple strains that work together in order to prosper and protect each other. In this study, we provide evidence for a very different view: biofilms are formed when bacterial strains compete with one another. We mixed together different strains of the widespread pathogen Pseudomonas aeruginosa and found that pairs often make bigger biofilms than either one alone. Rather than working together, however, we show that one strain normally kills the other off and that biofilm formation is actually a response to the damage of antibiotic warfare. Our work helps to explain the widespread observation that treating bacteria with clinical antibiotics can stimulate biofilm formation. When we treat bacteria, they respond as if the attack is coming from a foreign strain that must be outnumbered and outcompeted in a biofilm.
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Affiliation(s)
- Nuno M. Oliveira
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Integrative Systems Biology, University of Oxford, Oxford, United Kingdom
| | - Esteban Martinez-Garcia
- FAS Center for Systems Biology, University of Harvard, Cambridge, Massachusetts, United States of America
- Centro Nacional de Biotecnologia-CSIC, Campus de Cantoblanco, Madrid, Spain
| | - Joao Xavier
- FAS Center for Systems Biology, University of Harvard, Cambridge, Massachusetts, United States of America
- Memorial Sloan-Kettering Cancer Center, Computational Biology Program, New York, New York, United States of America
| | | | - Roberto Kolter
- Harvard Medical School, Department of Microbiology and Immunobiology, Boston, Massachusetts, United States of America
| | - Wook Kim
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Integrative Systems Biology, University of Oxford, Oxford, United Kingdom
- FAS Center for Systems Biology, University of Harvard, Cambridge, Massachusetts, United States of America
| | - Kevin R. Foster
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Integrative Systems Biology, University of Oxford, Oxford, United Kingdom
- FAS Center for Systems Biology, University of Harvard, Cambridge, Massachusetts, United States of America
- * E-mail:
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Lassek C, Burghartz M, Chaves-Moreno D, Otto A, Hentschker C, Fuchs S, Bernhardt J, Jauregui R, Neubauer R, Becher D, Pieper DH, Jahn M, Jahn D, Riedel K. A metaproteomics approach to elucidate host and pathogen protein expression during catheter-associated urinary tract infections (CAUTIs). Mol Cell Proteomics 2015; 14:989-1008. [PMID: 25673765 PMCID: PMC4390275 DOI: 10.1074/mcp.m114.043463] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Revised: 01/20/2015] [Indexed: 12/11/2022] Open
Abstract
Long-term catheterization inevitably leads to a catheter-associated bacteriuria caused by multispecies bacterial biofilms growing on and in the catheters. The overall goal of the presented study was (1) to unravel bacterial community structure and function of such a uropathogenic biofilm and (2) to elucidate the interplay between bacterial virulence and the human immune system within the urine. To this end, a metaproteomics approach combined with in vitro proteomics analyses was employed to investigate both, the pro- and eukaryotic protein inventory. Our proteome analyses demonstrated that the biofilm of the investigated catheter is dominated by three bacterial species, that is, Pseudomonas aeruginosa, Morganella morganii, and Bacteroides sp., and identified iron limitation as one of the major challenges in the bladder environment. In vitro proteome analysis of P. aeruginosa and M. morganii isolated from the biofilm revealed that these opportunistic pathogens are able to overcome iron restriction via the production of siderophores and high expression of corresponding receptors. Notably, a comparison of in vivo and in vitro protein profiles of P. aeruginosa and M. morganii also indicated that the bacteria employ different strategies to adapt to the urinary tract. Although P. aeruginosa seems to express secreted and surface-exposed proteases to escape the human innate immune system and metabolizes amino acids, M. morganii is able to take up sugars and to degrade urea. Most interestingly, a comparison of urine protein profiles of three long-term catheterized patients and three healthy control persons demonstrated the elevated level of proteins associated with neutrophils, macrophages, and the complement system in the patient's urine, which might point to a specific activation of the innate immune system in response to biofilm-associated urinary tract infections. We thus hypothesize that the often asymptomatic nature of catheter-associated urinary tract infections might be based on a fine-tuned balance between the expression of bacterial virulence factors and the human immune system.
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Affiliation(s)
- Christian Lassek
- From the ‡Institute of Microbiology, University of Greifswald, 17489 Greifswald, Friedrich-Ludwig-Jahn-Strasse 15, Germany; §Institute of Microbiology, Technische Universität Braunschweig, 38106 Braunschweig, Spielmannstrasse 7, Germany
| | - Melanie Burghartz
- §Institute of Microbiology, Technische Universität Braunschweig, 38106 Braunschweig, Spielmannstrasse 7, Germany
| | - Diego Chaves-Moreno
- ¶Microbial Interactions and Processes Research Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Inhoffenstrasse 7, Germany
| | - Andreas Otto
- From the ‡Institute of Microbiology, University of Greifswald, 17489 Greifswald, Friedrich-Ludwig-Jahn-Strasse 15, Germany
| | - Christian Hentschker
- From the ‡Institute of Microbiology, University of Greifswald, 17489 Greifswald, Friedrich-Ludwig-Jahn-Strasse 15, Germany
| | - Stephan Fuchs
- From the ‡Institute of Microbiology, University of Greifswald, 17489 Greifswald, Friedrich-Ludwig-Jahn-Strasse 15, Germany
| | - Jörg Bernhardt
- From the ‡Institute of Microbiology, University of Greifswald, 17489 Greifswald, Friedrich-Ludwig-Jahn-Strasse 15, Germany
| | - Ruy Jauregui
- ¶Microbial Interactions and Processes Research Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Inhoffenstrasse 7, Germany
| | | | - Dörte Becher
- From the ‡Institute of Microbiology, University of Greifswald, 17489 Greifswald, Friedrich-Ludwig-Jahn-Strasse 15, Germany
| | - Dietmar H Pieper
- ¶Microbial Interactions and Processes Research Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Inhoffenstrasse 7, Germany
| | - Martina Jahn
- §Institute of Microbiology, Technische Universität Braunschweig, 38106 Braunschweig, Spielmannstrasse 7, Germany
| | - Dieter Jahn
- §Institute of Microbiology, Technische Universität Braunschweig, 38106 Braunschweig, Spielmannstrasse 7, Germany
| | - Katharina Riedel
- From the ‡Institute of Microbiology, University of Greifswald, 17489 Greifswald, Friedrich-Ludwig-Jahn-Strasse 15, Germany; ¶Microbial Interactions and Processes Research Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Inhoffenstrasse 7, Germany;
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11
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Dalhoff A. Pharmacokinetics and pharmacodynamics of aerosolized antibacterial agents in chronically infected cystic fibrosis patients. Clin Microbiol Rev 2014; 27:753-82. [PMID: 25278574 PMCID: PMC4187638 DOI: 10.1128/cmr.00022-14] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacteria adapt to growth in lungs of patients with cystic fibrosis (CF) by selection of heterogeneously resistant variants that are not detected by conventional susceptibility testing but are selected for rapidly during antibacterial treatment. Therefore, total bacterial counts and antibiotic susceptibilities are misleading indicators of infection and are not helpful as guides for therapy decisions or efficacy endpoints. High drug concentrations delivered by aerosol may maximize efficacy, as decreased drug susceptibilities of the pathogens are compensated for by high target site concentrations. However, reductions of the bacterial load in sputum and improvements in lung function were within the same ranges following aerosolized and conventional therapies. Furthermore, the use of conventional pharmacokinetic/pharmacodynamic (PK/PD) surrogates correlating pharmacokinetics in serum with clinical cure and presumed or proven eradication of the pathogen as a basis for PK/PD investigations in CF patients is irrelevant, as minimization of systemic exposure is one of the main objectives of aerosolized therapy; in addition, bacterial pathogens cannot be eradicated, and chronic infection cannot be cured. Consequently, conventional PK/PD surrogates are not applicable to CF patients. It is nonetheless obvious that systemic exposure of patients, with all its sequelae, is minimized and that the burden of oral treatment for CF patients suffering from chronic infections is reduced.
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Affiliation(s)
- Axel Dalhoff
- University Medical Center Schleswig-Holstein, Institute for Infection Medicine, Kiel, Germany
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Al-Maleki AR, Mariappan V, Vellasamy KM, Shankar EM, Tay ST, Vadivelu J. Enhanced intracellular survival and epithelial cell adherence abilities of Burkholderia pseudomallei morphotypes are dependent on differential expression of virulence-associated proteins during mid-logarithmic growth phase. J Proteomics 2014; 106:205-20. [DOI: 10.1016/j.jprot.2014.04.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 03/21/2014] [Accepted: 04/02/2014] [Indexed: 10/25/2022]
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Pessi G, Braunwalder R, Grunau A, Omasits U, Ahrens CH, Eberl L. Response of Burkholderia cenocepacia H111 to micro-oxia. PLoS One 2013; 8:e72939. [PMID: 24023794 PMCID: PMC3759415 DOI: 10.1371/journal.pone.0072939] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 07/15/2013] [Indexed: 12/20/2022] Open
Abstract
B. cenocepacia is an opportunistic human pathogen that is particularly problematic for patients suffering from cystic fibrosis (CF). In the CF lung bacteria grow to high densities within the viscous mucus that is limited in oxygen. Pseudomonas aeruginosa, the dominant pathogen in CF patients, is known to grow and survive under oxygen-limited to anaerobic conditions by using micro-oxic respiration, denitrification and fermentative pathways. In contrast, inspection of the genome sequences of available B. cenocepacia strains suggested that B. cenocepacia is an obligate aerobic and non-fermenting bacterium. In accordance with the bioinformatics analysis we observed that B. cenocepacia H111 is able to grow with as little as 0.1% O2 but not under strictly anoxic conditions. Phenotypic analyses revealed that H111 produced larger amounts of biofilm, pellicle and proteases under micro-oxic conditions (0.5%–5% O2, i.e. conditions that mimic those encountered in CF lung infection), and was more resistant to several antibiotics. RNA-Seq and shotgun proteomics analyses of cultures of B. cenocepacia H111 grown under micro-oxic and aerobic conditions showed up-regulation of genes involved in the synthesis of the exopolysaccharide (EPS) cepacian as well as several proteases, two isocitrate lyases and other genes potentially important for life in micro-oxia. Data deposition: RNA-Seq raw data files are accessible through the GEO Series accession number GSE48585. MS data have been deposited in the ProteomeXchange database (PXD000270).
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Affiliation(s)
- Gabriella Pessi
- Department of Microbiology, University of Zurich, Zürich, Switzerland
- * E-mail:
| | | | - Alexander Grunau
- Department of Microbiology, University of Zurich, Zürich, Switzerland
| | - Ulrich Omasits
- Institute of Molecular Life Sciences, University of Zurich, Zürich, Switzerland
| | - Christian H. Ahrens
- Institute of Molecular Life Sciences, University of Zurich, Zürich, Switzerland
| | - Leo Eberl
- Department of Microbiology, University of Zurich, Zürich, Switzerland
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Forier K, Messiaen AS, Raemdonck K, Deschout H, Rejman J, De Baets F, Nelis H, De Smedt SC, Demeester J, Coenye T, Braeckmans K. Transport of nanoparticles in cystic fibrosis sputum and bacterial biofilms by single-particle tracking microscopy. Nanomedicine (Lond) 2013; 8:935-49. [DOI: 10.2217/nnm.12.129] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Aim: The aim of this study was to evaluate the effect of the surface functionalization of model nanoparticles on their mobility in bacterial biofilms and cystic fibrosis sputum. Materials & methods: With single-particle tracking microscopy, the mobility of 0.1- and 0.2-µm fluorescent polyethylene glycol (PEG) modified, carboxylate- and N,N-dimethylethylenediamine-modified polystyrene nanospheres were evaluated in fresh cystic fibrosis sputum, as well as Burkholderia multivorans and Pseudomonas aeruginosa biofilms. Results: PEGylation increased the mobility of the particles in sputum and biofilms, while the charged nanospheres were strongly immobilized. However, the transport of the PEGylated nanoparticles was lower in sputum compared with biofilms. Furthermore, the particle transport showed heterogeneity in samples originating from different patients. Conclusion: This study’s data suggest that for future nanocarrier design it will be essential to combine PEGylation with a targeting moiety to ensure sufficient mobility in mucus and a better accumulation of the nanoparticles in the biofilm. Original submitted 14 February 2012; Revised submitted 24 July 2012; Published online 5 October 2012
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Affiliation(s)
- Katrien Forier
- Ghent University, Harelbekestraat 72, 9000 Ghent, Ghent, Belgium
- Center for Nano- and Biophotonics, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium
| | | | - Koen Raemdonck
- Ghent University, Harelbekestraat 72, 9000 Ghent, Ghent, Belgium
| | - Hendrik Deschout
- Ghent University, Harelbekestraat 72, 9000 Ghent, Ghent, Belgium
- Center for Nano- and Biophotonics, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium
| | - Joanna Rejman
- Ghent University, Harelbekestraat 72, 9000 Ghent, Ghent, Belgium
| | - Frans De Baets
- Department of Pediatrics, University Hospital of Ghent, De Pintelaan 185, 9000 Ghent, Ghent, Belgium
| | - Hans Nelis
- Ghent University, Harelbekestraat 72, 9000 Ghent, Ghent, Belgium
| | | | - Joseph Demeester
- Ghent University, Harelbekestraat 72, 9000 Ghent, Ghent, Belgium
| | - Tom Coenye
- Ghent University, Harelbekestraat 72, 9000 Ghent, Ghent, Belgium
| | - Kevin Braeckmans
- Ghent University, Harelbekestraat 72, 9000 Ghent, Ghent, Belgium
- Center for Nano- and Biophotonics, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium
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Ramli NSK, Eng Guan C, Nathan S, Vadivelu J. The effect of environmental conditions on biofilm formation of Burkholderia pseudomallei clinical isolates. PLoS One 2012; 7:e44104. [PMID: 22970167 PMCID: PMC3435415 DOI: 10.1371/journal.pone.0044104] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 07/30/2012] [Indexed: 01/30/2023] Open
Abstract
Burkholderia pseudomallei, a Gram-negative saprophytic bacterium, is the causative agent of the potentially fatal melioidosis disease in humans. In this study, environmental parameters including temperature, nutrient content, pH and the presence of glucose were shown to play a role in in vitro biofilm formation by 28 B. pseudomallei clinical isolates, including four isolates with large colony variants (LCVs) and small colony variants (SCVs) morphotypes. Enhanced biofilm formation was observed when the isolates were tested in LB medium, at 30°C, at pH 7.2, and in the presence of as little as 2 mM glucose respectively. It was also shown that all SVCs displayed significantly greater capacity to form biofilms than the corresponding LCVs when cultured in LB at 37°C. In addition, octanoyl-homoserine lactone (C8-HSL), a quorum sensing molecule, was identified by mass spectrometry analysis in bacterial isolates referred to as LCV CTH, LCV VIT, SCV TOM, SCV CTH, 1 and 3, and the presence of other AHL's with higher masses; decanoyl-homoserine lactone (C10-HSL) and dodecanoyl-homoserine lactone (C12-HSL) were also found in all tested strain in this study. Last but not least, we had successfully acquired two Bacillus sp. soil isolates, termed KW and SA respectively, which possessed strong AHLs degradation activity. Biofilm formation of B. pseudomallei isolates was significantly decreased after treated with culture supernatants of KW and SA strains, demonstrating that AHLs may play a role in B. pseudomallei biofilm formation.
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Affiliation(s)
- Nur Siti K. Ramli
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chua Eng Guan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Sheila Nathan
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- * E-mail:
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Characterization of the poly-β-1,6-N-acetylglucosamine polysaccharide component of Burkholderia biofilms. Appl Environ Microbiol 2011; 77:8303-9. [PMID: 21984237 DOI: 10.1128/aem.05814-11] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We demonstrated the production of poly-β-1,6-N-acetylglucosamine (PNAG) polysaccharide in the biofilms of Burkholderia multivorans, Burkholderia vietnamiensis, Burkholderia ambifaria, Burkholderia cepacia, and Burkholderia cenocepacia using an immunoblot assay for PNAG. These results were confirmed by further studies, which showed that the PNAG hydrolase, dispersin B, eliminated immunoreactivity of extracts from the species that were tested (B. cenocepacia and B. multivorans). Dispersin B also inhibited biofilm formation and dispersed preformed biofilms of Burkholderia species. These results imply a role for PNAG in the maintenance of Burkholderia biofilm integrity. While PNAG was present in biofilms of all of the wild-type test organisms, a ΔpgaBC mutant of B. multivorans (Mu5) produced no detectable PNAG, indicating that these genes are needed for Burkholderia PNAG formation. Furthermore, restoration of PNAG production in PNAG negative E. coli TRXWMGΔC (ΔpgaC) by complementation with B. multivorans pgaBCD confirmed the involvement of these genes in Burkholderia PNAG production. While the confocal scanning laser microscopy of untreated wild-type B. multivorans showed thick, multilayered biofilm, Mu5 and dispersin B-treated wild-type biofilms were thin, poorly developed, and disrupted, confirming the involvement of PNAG in B. multivorans biofilm formation. Thus, PNAG appears to be an important component of Burkholderia biofilms, potentially contributing to its resistance to multiple antibiotics and persistence during chronic infections, including cystic fibrosis-associated infection.
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Vial L, Chapalain A, Groleau MC, Déziel E. The various lifestyles of theBurkholderia cepaciacomplex species: a tribute to adaptation. Environ Microbiol 2010; 13:1-12. [DOI: 10.1111/j.1462-2920.2010.02343.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Coenye T. Social interactions in the Burkholderia cepacia complex: biofilms and quorum sensing. Future Microbiol 2010; 5:1087-99. [DOI: 10.2217/fmb.10.68] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Burkholderia cepacia complex bacteria are opportunistic pathogens that cause respiratory tract infections in susceptible patients, mainly people with cystic fibrosis. There is convincing evidence that B. cepacia complex bacteria can form biofilms, not only on abiotic surfaces (e.g., glass and plastics), but also on biotic surfaces such as epithelial cells, leading to the suggestion that biofilm formation plays a key role in persistent infection of cystic fibrosis lungs. This article presents an overview of the molecular mechanisms involved in B. cepacia complex biofilm formation, the increased resistance of sessile B. cepacia complex cells and the role of quorum sensing in B. cepacia complex biofilm formation.
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Affiliation(s)
- Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Harelbekestraat 72, B-9000 Gent, Belgium
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Phase variation has a role in Burkholderia ambifaria niche adaptation. ISME JOURNAL 2009; 4:49-60. [PMID: 19710710 DOI: 10.1038/ismej.2009.95] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Members of the Burkholderia cepacia complex (Bcc), such as B. ambifaria, are effective biocontrol strains, for instance, as plant growth-promoting bacteria; however, Bcc isolates can also cause severe respiratory infections in people suffering from cystic fibrosis (CF). No distinction is known between isolates from environmental and human origins, suggesting that the natural environment is a potential source of infectious Bcc species. While investigating the presence and role of phase variation in B. ambifaria HSJ1, an isolate recovered from a CF patient, we identified stable variants that arose spontaneously irrespective of the culture conditions. Phenotypic and proteomic approaches revealed that the transition from wild-type to variant types affects the expression of several putative virulence factors. By using four different infection models (Drosophila melanogaster, Galleria mellonella, macrophages and Dictyostelium discoideum), we showed that the wild-type was more virulent than the variant. It may be noted that the variant showed reduced replication in a human monocyte cell line when compared with the wild-type. On the other hand, the variant of isolate HSJ1 was more competitive in colonizing plant roots than the wild-type. Furthermore, we observed that only clinical B. ambifaria isolates generated phase variants, and that these variants showed the same phenotypes as observed with the HSJ1 variant. Finally, we determined that environmental B. ambifaria isolates showed traits that were characteristic of variants derived from clinical isolates. Our study therefore suggest that B. ambifaria uses phase variation to adapt to drastically different environments: the lung of patients with CF or the rhizosphere.
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Combination antibiotic susceptibility of biofilm-grown Burkholderia cepacia and Pseudomonas aeruginosa isolated from patients with pulmonary exacerbations of cystic fibrosis. Eur J Clin Microbiol Infect Dis 2009; 28:1275-9. [DOI: 10.1007/s10096-009-0774-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 06/20/2009] [Indexed: 12/22/2022]
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Brackman G, Hillaert U, Van Calenbergh S, Nelis HJ, Coenye T. Use of quorum sensing inhibitors to interfere with biofilm formation and development in Burkholderia multivorans and Burkholderia cenocepacia. Res Microbiol 2009; 160:144-51. [DOI: 10.1016/j.resmic.2008.12.003] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 12/09/2008] [Accepted: 12/10/2008] [Indexed: 12/11/2022]
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Mrsny RJ. Lessons from nature: "Pathogen-Mimetic" systems for mucosal nano-medicines. Adv Drug Deliv Rev 2009; 61:172-92. [PMID: 19146895 DOI: 10.1016/j.addr.2008.09.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Accepted: 09/22/2008] [Indexed: 12/13/2022]
Abstract
Mucosal surfaces establish an interface with external environments that provide a protective barrier with the capacity to selectively absorb and secrete materials important for homeostasis of the organism. In man, mucosal surfaces such as those in the gastrointestinal tract, respiratory tree and genitourinary system also represent significant barrier to the successful administration of certain pharmaceutical agents and the delivery of newly designed nano-scale therapeutic systems. This review examines morphological, physiological and biochemical aspects of these mucosal barriers and presents currently understood mechanisms used by a variety of virulence factors used by pathogenic bacteria to overcome various aspects of these mucosal barriers. Such information emphasizes the impediments that biologically active materials must overcome for absorption across these mucosal surfaces and provides a template for strategies to overcome these barriers for the successful delivery of nano-scale bioactive materials, also known as nano-medicines.
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De Soyza A, Silipo A, Lanzetta R, Govan JR, Molinaro A. Chemical and biological features of Burkholderia cepacia complex lipopolysaccharides. Innate Immun 2008; 14:127-44. [PMID: 18562572 DOI: 10.1177/1753425908093984] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Burkholderia cepacia complex comprises 10 closely related Gram-negative organisms all of which appear capable of causing disease in humans. These organisms appear of particular relevance to patients with cystic fibrosis. Lipopolysaccharide (LPS) is an important virulence determinant in Gram-negative pathogens. In this review, we highlight important data within the field commenting on LPS/lipid A structure-to-function relationships and cytokine induction capacity of Burkholderia strains studied so far.
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Affiliation(s)
- Anthony De Soyza
- Transplantation and Immunobiology Group, Institute of Cellular Medicine, Newcastle University and The Freeman Hospital, Newcastle-upon-Tyne, UK.
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