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Willcocks SJ, Denman C, Cia F, McCarthy E, Cuccui J, Wren BW. Virulence of the emerging pathogen, Burkholderia pseudomallei, depends upon the O-linked oligosaccharyltransferase, PglL. Future Microbiol 2021; 15:241-257. [PMID: 32271107 PMCID: PMC7611010 DOI: 10.2217/fmb-2019-0165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Aim We sought to characterize the contribution of the O-OTase, PglL, to virulence in two Burkholderia spp. by comparing isogenic mutants in Burkholderia pseudomallei with the related species, Burkholderia thailandensis. Materials & methods We utilized an array of in vitro assays in addition to Galleria mellonella and murine in vivo models to assess virulence of the mutant and wild-type strains in each Burkholderia species. Results We found that pglL contributes to biofilm and twitching motility in both species. PglL uniquely affected morphology; cell invasion; intracellular motility; plaque formation and intergenus competition in B. pseudomallei. This mutant was attenuated in the murine model, and extended survival in a vaccine-challenge experiment. Conclusion Our data support a broad role for pglL in bacterial fitness and virulence, particularly in B. pseudomallei.
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Affiliation(s)
| | - Carmen Denman
- The London School of Hygiene & Tropical Medicine, WC1E 7HT, London, UK
| | - Felipe Cia
- The London School of Hygiene & Tropical Medicine, WC1E 7HT, London, UK
| | | | - Jon Cuccui
- The London School of Hygiene & Tropical Medicine, WC1E 7HT, London, UK
| | - Brendan W Wren
- The London School of Hygiene & Tropical Medicine, WC1E 7HT, London, UK
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Hulbah M, Croxen MA, Tyrrell GJ. Phenotypic changes in group B streptococci grown in the presence of the polyols, erythritol, sorbitol and mannitol. BMC Microbiol 2021; 21:145. [PMID: 33985431 PMCID: PMC8117501 DOI: 10.1186/s12866-021-02208-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 04/29/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Group B streptococci (GBS) are important neonatal bacterial pathogens that can cause severe invasive disease in the newborn. It is thought that in many cases of invasive neonatal GBS disease, the bacteria ascend the vagina into the uterus and infect the amniotic fluid surrounding the fetus. Important constituents of this environment include the polyols or sugar alcohols of which erythritol, sorbitol and mannitol are examples. The aim of our study was to investigate the effect of polyols on GBS grown in media containing these sugar alcohols. RESULTS GBS incubated in varying concentrations of polyols (erythritol, sorbitol or mannitol) did not display any significant enhancement or inhibition of bacterial growth. However, growth of GBS in the presence of erythritol significantly increased the surface expression of GBS-PGK (a plasminogen binding protein) 1.25 to 1.5-fold depending on the erythritol concentration and significantly enhanced the survival in human blood 3X to 18X depending on the concentration of polyol used. Interestingly, GBS grown in 1% erythritol significantly increased invasion by the bacteria of HeLa cells (epithelial cell line) (150% vs 100%) however, at higher concentrations (2% or 4% of polyol) the number of CFUs was significantly reduced (55-75% vs 100%) suggesting higher concentrations of polyols may inhibit invasion. Erythritol also increased GBS hemolytic activity as well as enhancing biofilm formation 1.4X to 3.3X depending on the concentration of polyol used. CONCLUSIONS GBS grown in the presence of polyols alters the bacteria's phenotype resulting in changes associated with GBS virulence. This effect was greatest for the polyol erythritol.
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Affiliation(s)
- Maram Hulbah
- Division of Diagnostic and Applied Microbiology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Canada
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif, Saudi Arabia
| | - Matthew A Croxen
- Division of Diagnostic and Applied Microbiology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Canada
- Alberta Precision Laboratories-Public Health, Edmonton, Alberta, T6G 2J2, Canada
| | - Gregory J Tyrrell
- Division of Diagnostic and Applied Microbiology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Canada.
- Alberta Precision Laboratories-Public Health, Edmonton, Alberta, T6G 2J2, Canada.
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Peeters C, Depoorter E, Canck ED, Vandamme P. Genome sequence-based curation of PubMLST data challenges interspecies recombination in the Burkholderia cepacia complex. Future Microbiol 2020; 15:1091-1093. [DOI: 10.2217/fmb-2020-0027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Charlotte Peeters
- Laboratory of Microbiology, Department of Biochemistry & Microbiology, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Eliza Depoorter
- Laboratory of Microbiology, Department of Biochemistry & Microbiology, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Evelien De Canck
- Laboratory of Microbiology, Department of Biochemistry & Microbiology, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Peter Vandamme
- Laboratory of Microbiology, Department of Biochemistry & Microbiology, Faculty of Sciences, Ghent University, Ghent, Belgium
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Environmental interactions are regulated by temperature in Burkholderia seminalis TC3.4.2R3. Sci Rep 2019; 9:5486. [PMID: 30940839 PMCID: PMC6445077 DOI: 10.1038/s41598-019-41778-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 03/12/2019] [Indexed: 11/08/2022] Open
Abstract
Burkholderia seminalis strain TC3.4.2R3 is an endophytic bacterium isolated from sugarcane roots that produces antimicrobial compounds, facilitating its ability to act as a biocontrol agent against phytopathogenic bacteria. In this study, we investigated the thermoregulation of B. seminalis TC3.4.2R3 at 28 °C (environmental stimulus) and 37 °C (host-associated stimulus) at the transcriptional and phenotypic levels. The production of biofilms and exopolysaccharides such as capsular polysaccharides and the biocontrol of phytopathogenic fungi were enhanced at 28 °C. At 37 °C, several metabolic pathways were activated, particularly those implicated in energy production, stress responses and the biosynthesis of transporters. Motility, growth and virulence in the Galleria mellonella larvae infection model were more significant at 37 °C. Our data suggest that the regulation of capsule expression could be important in virulence against G. mellonella larvae at 37 °C. In contrast, B. seminalis TC3.4.2R3 failed to cause death in infected BALB/c mice, even at an infective dose of 107 CFU.mL-1. We conclude that temperature drives the regulation of gene expression in B. seminalis during its interactions with the environment.
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Characterization of a novel regulatory pathway for mannitol metabolism and its coordination with biofilm formation in Mycobacterium smegmatis. J Genet Genomics 2018; 45:477-488. [DOI: 10.1016/j.jgg.2018.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/26/2018] [Indexed: 01/03/2023]
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Murphy MP, Caraher E. Current and Emerging Therapies for the Treatment of Cystic Fibrosis or Mitigation of Its Symptoms. Drugs R D 2016; 16:1-17. [PMID: 26747453 PMCID: PMC4767716 DOI: 10.1007/s40268-015-0121-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Clinical presentation of the chronic, heritable condition cystic fibrosis (CF) is complex, with a diverse range of symptoms often affecting multiple organs with varying severity. The primary source of morbidity and mortality is due to progressive destruction of the airways attributable to chronic inflammation arising from microbial colonisation. Antimicrobial therapy combined with practises to remove obstructive mucopurulent deposits form the cornerstone of current therapy. However, new treatment options are emerging which offer, for the first time, the opportunity to effect remission from the underlying cause of CF. Here, we discuss these therapies, their mechanisms of action, and their successes and failures in order to illustrate the shift in the nature of how CF will likely be managed into the future.
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Affiliation(s)
- Mark P Murphy
- Centre for Microbial-Host Interactions, Centre of Applied Science for Health, Institute of Technology Tallaght, Dublin 24, Ireland.
| | - Emma Caraher
- Centre for Microbial-Host Interactions, Centre of Applied Science for Health, Institute of Technology Tallaght, Dublin 24, Ireland.
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Moore JE, Rendall JC, Downey DG. Pseudomonas aeruginosa displays an altered phenotype in vitro when grown in the presence of mannitol. Br J Biomed Sci 2015; 72:115-9. [PMID: 26510267 DOI: 10.1080/09674845.2015.11666807] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
D-mannitol has been approved in dry powder formulation as an effective antimucolytic agent in patients with cystic fibrosis. What is not known is the effect of adding a metabolisable sugar on the biology of chronic bacterial pathogens in the CF lung. Therefore, a series of simple in vitro experiments were performed to examine the effect of adding D-mannitol on the phenotype of the CF respiratory pathogens Pseudomonas aeruginosa and Burkholderia cenocepacia. Clinical isolates (n = 86) consisting of P. aeruginosa (n = 51), B. cenocepacia (n = 26), P. putida (n = 4), Stenotrophomonas maltophila (n = 3) and Pseudomonas spp. (n = 2) were examined by supplementing basal nutrient agar with varying concentrations of D-mannitol (0-20% [w/v]) and subsequently examining for any change in microbial phenotype. The effect of supplementation with mannitol was four-fold, namely i) To increase the proliferation and increase in cell density of all CF organisms examined, with an optimal concentration of 2-4% (w/v) D-mannitol. No such increase in cell proliferation was observed when mannitol was substituted with sodium chloride. ii) Enhanced pigment production was observed in 2/51 (3.9%) of the P. aeruginosa isolates examined, in one of the P. putida isolates, and in 3/26 (11.5%) of the B. cenocepacia isolates examined. iii). When examined at 4.0% (w/v) supplementation with mannitol, 11/51 (21.6%) P. aeruginosa isolates and 3/26 (11.5%) B. cenocepacia isolates were seen to exhibit the altered adhesion phenotype. iv). With respect to the altered mucoid phenotype, 5/51 (9.8%) P. aeruginosa produced this phenotype when grown at 4% mannitol. Mucoid production was greatest at 4%, was poor at 10% and absent at 20% (w/v) mannitol. The altered mucoid phenotype was not observed in the B. cenocepacia isolates or any of the other clinical taxa examined. Due consideration therefore needs to be given, where there is altered physiology within the small airways, leading to a potentially altered biological state of the colonising microorganisms in novel inhaled pharmaceutical interventions in CF, particularly those, which are not designated as antimicrobial agents.
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Denman CC, Robinson MT, Sass AM, Mahenthiralingam E, Brown AR. Growth on mannitol-rich media elicits a genome-wide transcriptional response in Burkholderia multivorans that impacts on multiple virulence traits in an exopolysaccharide-independent manner. MICROBIOLOGY-SGM 2013; 160:187-197. [PMID: 24196427 DOI: 10.1099/mic.0.072975-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In common with other members of the Burkholderia cepacia complex (BCC), Burkholderia multivorans is capable of producing exopolysaccharide (EPS) when grown on certain mannitol-rich media. The significance of the resulting mucoid phenotype and the genome-wide response to mannitol has never been characterized despite its clinical relevance following the approval of a dried-powder preparation of mannitol as an inhaled osmolyte therapy for cystic fibrosis (CF) patients. In the present study we defined the transcriptional response of B. multivorans ATCC 17616, a model genome-sequenced strain of environmental origin, to growth on mannitol-rich yeast extract media (MYEM). EPS-dependent and -independent impact of MYEM on virulence-associated traits was assessed in both strain ATCC 17616 and the CF isolate B. multivorans C1576. Our studies revealed a significant transcriptional response to MYEM encompassing approximately 23 % of predicted genes within the genome. Strikingly, this transcriptional response identified that EPS induction occurs in ATCC 17616 without the upregulation of the bce-I and bce-II EPS gene clusters, despite their pivotal role in EPS biosynthesis. Of approximately 20 differentially expressed putative virulence factors, 16 exhibited upregulation including flagella, ornibactin, oxidative stress proteins and phospholipases. MYEM-grown B. multivorans also exhibited enhanced motility, biofilm formation and epithelial cell invasion. In contrast to these potential virulence enhancements, MYEM-grown B. multivorans C1576 showed attenuated virulence in the Galleria mellonella infection model. All of the observed phenotypic responses occurred independently of EPS production, highlighting the profound impact that mannitol-based growth has on the physiology and virulence of B. multivorans.
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Affiliation(s)
- Carmen C Denman
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Matthew T Robinson
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Andrea M Sass
- Organisms & Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - Eshwar Mahenthiralingam
- Organisms & Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - Alan R Brown
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
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