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Horikawa T, Hung LW, Kim HB, Shaya D, Kim CY, Terwilliger TC, Yamashita E, Aoki M, Okada U, Murakami S. BpeB, a major resistance-nodulation-cell division transporter from Burkholderia cenocepacia: construct design, crystallization and preliminary structural analysis. Acta Crystallogr F Struct Biol Commun 2018; 74:710-716. [PMID: 30387776 PMCID: PMC6213979 DOI: 10.1107/s2053230x18013547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 09/24/2018] [Indexed: 11/11/2022] Open
Abstract
Burkholderia cenocepacia is an opportunistic pathogen that infects cystic fibrosis patients, causing pneumonia and septicemia. B. cenocepacia has intrinsic antibiotic resistance against monobactams, aminoglycosides, chloramphenicol and fluoroquinolones that is contributed by a homologue of BpeB, which is a member of the resistance-nodulation-cell division (RND)-type multidrug-efflux transporters. Here, the cloning, overexpression, purification, construct design for crystallization and preliminary X-ray diffraction analysis of this BpeB homologue from B. cenocepacia are reported. Two truncation variants were designed to remove possible disordered regions based on comparative sequence and structural analysis to salvage the wild-type protein, which failed to crystallize. The 17-residue carboxyl-terminal truncation yielded crystals that diffracted to 3.6 Å resolution. The efflux function measured using minimal inhibitory concentration assays indicated that the truncation decreased, but did not eliminate, the efflux activity of the transporter.
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Affiliation(s)
- Tomonari Horikawa
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Li-Wei Hung
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Heung-Bok Kim
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - David Shaya
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Chang-Yub Kim
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Thomas C. Terwilliger
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
- New Mexico Consortium, Los Alamos, NM 87544, USA
| | - Eiki Yamashita
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Maho Aoki
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Ui Okada
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Satoshi Murakami
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
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Assani K, Shrestha CL, Rinehardt H, Zhang S, Robledo-Avila F, Wellmerling J, Partida-Sanchez S, Cormet-Boyaka E, Reynolds SD, Schlesinger LS, Kopp BT. AR-13 reduces antibiotic-resistant bacterial burden in cystic fibrosis phagocytes and improves cystic fibrosis transmembrane conductance regulator function. J Cyst Fibros 2018; 18:622-629. [PMID: 30366849 DOI: 10.1016/j.jcf.2018.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 09/13/2018] [Accepted: 10/14/2018] [Indexed: 01/09/2023]
Abstract
BACKGROUND There are no effective treatments for Burkholderia cenocepacia in patients with cystic fibrosis (CF) due to bacterial multi-drug resistance and defective host killing. We demonstrated that decreased bacterial killing in CF is caused by reduced macrophage autophagy due to defective cystic fibrosis transmembrane conductance regulator (CFTR) function. AR-12 is a small molecule autophagy inducer that kills intracellular pathogens such as Francisella. We evaluated the efficacy of AR-12 and a new analogue AR-13 in reducing bacterial burden in CF phagocytes. METHODS Human CF and non-CF peripheral blood monocyte-derived macrophages, neutrophils, and nasal epithelial cells were exposed to CF bacterial strains in conjunction with treatment with antibiotics and/or AR compounds. RESULTS AR-13 and not AR-12 had growth inhibition on B. cenocepacia and methicillin-resistantStaphylococcus aureus (MRSA) in media alone. There was a 99% reduction in MRSA in CF macrophages, 71% reduction in Pseudomonas aeruginosa in CF neutrophils, and 70% reduction in non-CF neutrophils using AR-13. Conversely, there was no reduction in B. cenocepacia in infected CF and non-CF macrophages using AR-13 alone, but AR-13 and antibiotics synergistically reduced B. cenocepacia in CF macrophages. AR-13 improved autophagy in CF macrophages and CF patient-derived epithelial cells, and increased CFTR protein expression and channel function in CF epithelial cells. CONCLUSIONS The novel AR-12 analogue AR-13, in combination with antibiotics, reduced antibiotic-resistant bacterial burden in CF phagocytes, which correlated with increased autophagy and CFTR expression. AR-13 is a novel therapeutic for patients infected with B. cenocepacia and other resistant organisms that lack effective therapies.
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Affiliation(s)
- Kaivon Assani
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States
| | - Chandra L Shrestha
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States
| | - Hannah Rinehardt
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States
| | - Shuzhong Zhang
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States
| | - Frank Robledo-Avila
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States
| | - Jack Wellmerling
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, United States
| | - Santiago Partida-Sanchez
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States
| | - Estelle Cormet-Boyaka
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, United States
| | - Susan D Reynolds
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States
| | | | - Benjamin T Kopp
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States; Division of Pulmonary Medicine, Nationwide Children's Hospital, Columbus, OH, United States.
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Slachmuylders L, Van Acker H, Brackman G, Sass A, Van Nieuwerburgh F, Coenye T. Elucidation of the mechanism behind the potentiating activity of baicalin against Burkholderia cenocepacia biofilms. PLoS One 2018; 13:e0190533. [PMID: 29293658 PMCID: PMC5749847 DOI: 10.1371/journal.pone.0190533] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 12/16/2017] [Indexed: 11/19/2022] Open
Abstract
Reduced antimicrobial susceptibility due to resistance and tolerance has become a serious threat to human health. An approach to overcome this reduced susceptibility is the use of antibiotic adjuvants, also known as potentiators. These are compounds that have little or no antibacterial effect on their own but increase the susceptibility of bacterial cells towards antimicrobial agents. Baicalin hydrate, previously described as a quorum sensing inhibitor, is such a potentiator that increases the susceptibility of Burkholderia cenocepacia J2315 biofilms towards tobramycin. The goal of the present study is to elucidate the molecular mechanisms behind the potentiating activity of baicalin hydrate and related flavonoids. We first determined the effect of multiple flavonoids on susceptibility of B. cenocepacia J2315 towards tobramycin. Increased antibiotic susceptibility was most pronounced in combination with apigenin 7-O-glucoside and baicalin hydrate. For baicalin hydrate, also other B. cepacia complex strains and other antibiotics were tested. The potentiating effect was only observed for aminoglycosides and was both strain- and aminoglycoside-dependent. Subsequently, gene expression was compared between baicalin hydrate treated and untreated cells, in the presence and absence of tobramycin. This revealed that baicalin hydrate affected cellular respiration, resulting in increased reactive oxygen species production in the presence of tobramycin. We subsequently showed that baicalin hydrate has an impact on oxidative stress via several pathways including oxidative phosphorylation, glucarate metabolism and by modulating biosynthesis of putrescine. Furthermore, our data strongly suggest that the influence of baicalin hydrate on oxidative stress is unrelated to quorum sensing. Our data indicate that the potentiating effect of baicalin hydrate is due to modulating the oxidative stress response, which in turn leads to increased tobramycin-mediated killing.
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Affiliation(s)
- Lisa Slachmuylders
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Heleen Van Acker
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Gilles Brackman
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Andrea Sass
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | | | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
- * E-mail:
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4
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Vanhoutte B, Cappoen D, Maira BDM, Cools F, Torfs E, Coenye T, Martinet W, Caljon G, Maes L, Delputte P, Cos P. Optimization and characterization of a murine lung infection model for the evaluation of novel therapeutics against Burkholderia cenocepacia. J Microbiol Methods 2017; 139:181-188. [PMID: 28587856 DOI: 10.1016/j.mimet.2017.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 05/31/2017] [Accepted: 06/02/2017] [Indexed: 12/13/2022]
Abstract
Several B. cenocepacia mouse models are available to study the pulmonary infection by this Burkholderia cepacia complex (BCC) species. However, a characterized B. cenocepacia mouse model to evaluate the efficacy of potential new antibacterial therapies is not yet described. Therefore, we optimized and validated the course of infection (i.e. bacterial proliferation in lung, liver and spleen) and the efficacy of a reference antibiotic, tobramycin (TOB), in a mouse lung infection model. Furthermore, the local immune response and histological changes in lung tissue were studied during infection and treatment. A reproducible lung infection was observed when immunosuppressed BALB/c mice were infected with B. cenocepacia LMG 16656. Approximately 50 to 60% of mice infected with this BCC species demonstrated a dissemination to liver and spleen. TOB treatment resulted in a two log reduction in lung burden, prevented dissemination of B. cenocepacia to liver and spleen and significantly reduced levels of proinflammatory cytokines. As this mouse model is characterized by a reproducible course of infection and efficacy of TOB, it can be used as a tool for the in vivo evaluation of new antibacterial therapies.
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Affiliation(s)
- Bieke Vanhoutte
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Davie Cappoen
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Bidart de Macedo Maira
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Freya Cools
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Eveline Torfs
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ottergemsesteenweg 460, 9000 Gent, Belgium
| | - Wim Martinet
- Laboratory of Physiopharmacology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Guy Caljon
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Louis Maes
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Peter Delputte
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Paul Cos
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
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Balwan A, Nicolau DP, Wungwattana M, Zuckerman JB, Waters V. Clinafloxacin for Treatment of Burkholderia cenocepacia Infection in a Cystic Fibrosis Patient. Antimicrob Agents Chemother 2016; 60:1-5. [PMID: 26722110 PMCID: PMC4704148 DOI: 10.1128/aac.masthead.60-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Respiratory infection with Burkholderia cenocepacia is associated with accelerated decline in lung function and increased mortality in cystic fibrosis (CF) patients (A. M. Jones, M. E. Dodd, J. R. W. Govan, V. Barcus, C. J. Doherty, J. Morris, and A. K. Webb, Thorax 59:948-951, 2004, http://dx.doi.org/10.1136/thx.2003.017210). B. cenocepacia often possesses innate resistance to multiple antimicrobial classes, making eradication uncommon in established infection (P. B. Davis, Am J Respir Crit Care Med 173:475-482, 2006, http://dx.doi.org/10.1164/rccm.200505-840OE). We report the use of clinafloxacin in a CF patient with advanced B. cenocepacia infection, present pharmacokinetic (PK) data, and discuss the potential therapeutic role of clinafloxacin in patients with this condition.
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Affiliation(s)
- Akshu Balwan
- Division of Pulmonary & Critical Care, Maine Medical Center, Portland, Maine, USA
| | - David P Nicolau
- Center for Anti-Infective Research & Development, Hartford Hospital, Hartford, Connecticut, USA
| | | | - Jonathan B Zuckerman
- Division of Pulmonary & Critical Care, Maine Medical Center, Portland, Maine, USA
| | - Valerie Waters
- Division of Infectious Diseases, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Canada
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Aubert DF, Hamad MA, Valvano MA. A markerless deletion method for genetic manipulation of Burkholderia cenocepacia and other multidrug-resistant gram-negative bacteria. Methods Mol Biol 2014; 1197:311-327. [PMID: 25172289 DOI: 10.1007/978-1-4939-1261-2_18] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Genetic manipulation of multidrug-resistant bacteria is often difficult and hinders progress in understanding their physiology and pathogenesis. This book chapter highlights advances in genetic manipulation of Burkholderia cenocepacia, which are also applicable to other members of the Burkholderia cepacia complex and multidrug-resistant gram-negative bacteria of other genera. The method detailed here is based on the I-SceI homing endonuclease system, which can be efficiently used for chromosomal integration, deletion, and genetic replacement. This system creates markerless mutations and insertions without leaving a genetic scar and thus can be reused successively to generate multiple modifications in the same strain.
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Affiliation(s)
- Daniel F Aubert
- Department of Microbiology and Immunology, Centre for Human Immunology, University of Western Ontario, London, ON, Canada, N6A 5C1
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7
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Novotny LA, Amer AO, Brockson ME, Goodman SD, Bakaletz LO. Structural stability of Burkholderia cenocepacia biofilms is reliant on eDNA structure and presence of a bacterial nucleic acid binding protein. PLoS One 2013; 8:e67629. [PMID: 23799151 PMCID: PMC3682984 DOI: 10.1371/journal.pone.0067629] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 05/22/2013] [Indexed: 12/14/2022] Open
Abstract
Cystic fibrosis (CF) is the most common lethal inherited genetic disorder affection Caucasians. Even with medical advances, CF is life-shortening with patients typically surviving only to age 38. Infection of the CF lung by Burkholderia cenocepacia presents exceptional challenges to medical management of these patients as clinically this microbe is resistant to virtually all antibiotics, is highly transmissible and infection of CF patients with this microbe renders them ineligible for lung transplant, often the last lifesaving option. Here we have targeted two abundant components of the B. cenocepacia biofilm for immune intervention: extracellular DNA and DNABII proteins, the latter of which are bacterial nucleic acid binding proteins. Treatment of B. cenocepacia biofilms with antiserum directed at one of these DNABII proteins (integration host factor or IHF) resulted in significant disruption of the biofilm. Moreover, when anti-IHF mediated destabilization of a B. cenocepacia biofilm was combined with exposure to traditional antibiotics, B. cenocepacia resident within the biofilm and thereby typically highly resistant to the action of antibiotics, were now rendered susceptible to killing. Pre-incubation of B. cenocepacia with anti-IHF serum prior to exposure to murine CF macrophages, which are normally unable to effectively degrade ingested B. cenocepacia, resulted in a statistically significant increase in killing of phagocytized B. cenocepacia. Collectively, these findings support further development of strategies that target DNABII proteins as a novel approach for treatment of CF patients, particularly those whose lungs are infected with B. cenocepacia.
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Affiliation(s)
- Laura A. Novotny
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children’s Hospital, and The Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Amal O. Amer
- Department of Microbial Infection and Immunity, Center for Microbial Interface Biology and the Department of Internal Medicine, College of Medicine, and the Ohio State University, Columbus, Ohio, United States of America
| | - M. Elizabeth Brockson
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children’s Hospital, and The Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Steven D. Goodman
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children’s Hospital, and The Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Lauren O. Bakaletz
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children’s Hospital, and The Ohio State University College of Medicine, Columbus, Ohio, United States of America
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Udine C, Brackman G, Bazzini S, Buroni S, Van Acker H, Pasca MR, Riccardi G, Coenye T. Phenotypic and genotypic characterisation of Burkholderia cenocepacia J2315 mutants affected in homoserine lactone and diffusible signal factor-based quorum sensing systems suggests interplay between both types of systems. PLoS One 2013; 8:e55112. [PMID: 23383071 PMCID: PMC3557247 DOI: 10.1371/journal.pone.0055112] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 12/19/2012] [Indexed: 01/30/2023] Open
Abstract
Many putative virulence factors of Burkholderia cenocepacia are controlled by various quorum sensing (QS) circuits. These QS systems either use N-acyl homoserine lactones (AHL) or cis-2-dodecenoic acid ("Burkholderia diffusible signal factor", BDSF) as signalling molecules. Previous work suggested that there is little cross-talk between both types of systems. We constructed mutants in B. cenocepacia strain J2315, in which genes encoding CepI (BCAM1870), CciI (BCAM0239a) and the BDSF synthase (BCAM0581) were inactivated, and also constructed double (ΔcepIΔBCAM0581, ΔcciIΔBCAM0581 and ΔcepIΔcciI) mutants and a triple (ΔcepIΔcciIΔBCAM0581) mutant. Subsequently we investigated phenotypic properties (antibiotic susceptibility, biofilm formation, production of AHL and BDSF, protease activity and virulence in Caenorhabditis elegans) and measured gene expression in these mutants, and this in the presence and absence of added BDSF, AHL or both. The triple mutant was significantly more affected in biofilm formation, antimicrobial susceptibility, virulence in C. elegans, and protease production than either the single or double mutants. The ΔBCAM0581 mutant and the ΔcepIΔBCAM0581 and ΔcciIΔBCAM0581 double mutants produced significantly less AHL compared to the WT strain and the ΔcepI and ΔcciI single mutant, respectively. The expression of cepI and cciI in ΔBCAM0581, was approximately 3-fold and 7-fold (p<0.05) lower than in the WT, respectively. The observed differences in AHL production, expression of cepI and cciI and QS-controlled phenotypes in the ΔBCAM0581 mutant could (at least partially) be restored by addition of BDSF. Our data suggest that, in B. cenocepacia J2315, AHL and BDSF-based QS systems co-regulate the same set of genes, regulate different sets of genes that are involved in the same phenotypes and/or that the BDSF system controls the AHL-based QS system. As the expression of the gene encoding the C6-HSL synthase CciI (and to a lesser extent the C8-HSL synthase CepI) is partially controlled by BDSF, it seems likely that the BDSF QS systems controls AHL production through this system.
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Affiliation(s)
- Claudia Udine
- Dipartimento di Biologia e Biotecnologie, Università degli Studi di Pavia, Pavia, Italy
| | - Gilles Brackman
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Silvia Bazzini
- Dipartimento di Biologia e Biotecnologie, Università degli Studi di Pavia, Pavia, Italy
| | - Silvia Buroni
- Dipartimento di Biologia e Biotecnologie, Università degli Studi di Pavia, Pavia, Italy
| | - Heleen Van Acker
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Maria Rosalia Pasca
- Dipartimento di Biologia e Biotecnologie, Università degli Studi di Pavia, Pavia, Italy
| | - Giovanna Riccardi
- Dipartimento di Biologia e Biotecnologie, Università degli Studi di Pavia, Pavia, Italy
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
- * E-mail:
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Goldberg JB, Ganesan S, Comstock AT, Zhao Y, Sajjan US. Cable pili and the associated 22 kDa adhesin contribute to Burkholderia cenocepacia persistence in vivo. PLoS One 2011; 6:e22435. [PMID: 21811611 PMCID: PMC3141045 DOI: 10.1371/journal.pone.0022435] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Accepted: 06/27/2011] [Indexed: 01/02/2023] Open
Abstract
Background Infection by Burkholderia cenocepacia in cystic fibrosis (CF) patients is associated with poor clinical prognosis. Previously, we demonstrated that one of the highly transmissible strains, BC7, expresses cable pili and the associated 22 kDa adhesin, both of which contribute to BC7 binding to airway epithelial cells. However, the contribution of these factors to induce inflammation and bacterial persistence in vivo is not known. Methodology/Principal Findings Wild-type BC7 stimulated higher IL-8 responses than the BC7 cbl and BC7 adhA mutants in both CF and normal bronchial epithelial cells. To determine the role of cable pili and the associated adhesin, we characterized a mouse model of B. cenocepacia, where BC7 are suspended in Pseudomonas aeruginosa alginate. C57BL/6 mice were infected intratracheally with wild-type BC7 suspended in either alginate or PBS and were monitored for lung bacterial load and inflammation. Mice infected with BC7 suspended in PBS completely cleared the bacteria by 3 days and resolved the inflammation. In contrast, mice infected with BC7 suspended in alginate showed persistence of bacteria and moderate lung inflammation up to 5 days post-infection. Using this model, mice infected with the BC7 cbl and BC7 adhA mutants showed lower bacterial loads and mild inflammation compared to mice infected with wild-type BC7. Complementation of the BC7 cblS mutation in trans restored the capacity of this strain to persist in vivo. Immunolocalization of bacteria revealed wild-type BC7 in both airway lumen and alveoli, while the BC7 cbl and BC7 adhA mutants were found mainly in airway lumen and peribronchiolar region. Conclusions and Significance B. cenocepacia suspended in alginate can be used to determine the capacity of bacteria to persist and cause lung inflammation in normal mice. Both cable pili and adhesin contribute to BC7-stimulated IL-8 response in vitro, and BC7 persistence and resultant inflammation in vivo.
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Affiliation(s)
- Joanna B. Goldberg
- Department of Microbiology, University of Virginia Health System, Charlottesville, Virginia, United States of America
| | - Shyamala Ganesan
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Adam T. Comstock
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Ying Zhao
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Uma S. Sajjan
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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Bazzini S, Udine C, Sass A, Pasca MR, Longo F, Emiliani G, Fondi M, Perrin E, Decorosi F, Viti C, Giovannetti L, Leoni L, Fani R, Riccardi G, Mahenthiralingam E, Buroni S. Deciphering the role of RND efflux transporters in Burkholderia cenocepacia. PLoS One 2011; 6:e18902. [PMID: 21526150 PMCID: PMC3079749 DOI: 10.1371/journal.pone.0018902] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 03/11/2011] [Indexed: 12/02/2022] Open
Abstract
Burkholderia cenocepacia J2315 is representative of a highly problematic group of cystic fibrosis (CF) pathogens. Eradication of B. cenocepacia is very difficult with the antimicrobial therapy being ineffective due to its high resistance to clinically relevant antimicrobial agents and disinfectants. RND (Resistance-Nodulation-Cell Division) efflux pumps are known to be among the mediators of multidrug resistance in Gram-negative bacteria. Since the significance of the 16 RND efflux systems present in B. cenocepacia (named RND-1 to -16) has been only partially determined, the aim of this work was to analyze mutants of B. cenocepacia strain J2315 impaired in RND-4 and RND-9 efflux systems, and assess their role in the efflux of toxic compounds. The transcriptomes of mutants deleted individually in RND-4 and RND-9 (named D4 and D9), and a double-mutant in both efflux pumps (named D4-D9), were compared to that of the wild-type B. cenocepacia using microarray analysis. Microarray data were confirmed by qRT-PCR, phenotypic experiments, and by Phenotype MicroArray analysis. The data revealed that RND-4 made a significant contribution to the antibiotic resistance of B. cenocepacia, whereas RND-9 was only marginally involved in this process. Moreover, the double mutant D4-D9 showed a phenotype and an expression profile similar to D4. The microarray data showed that motility and chemotaxis-related genes appeared to be up-regulated in both D4 and D4–D9 strains. In contrast, these gene sets were down-regulated or expressed at levels similar to J2315 in the D9 mutant. Biofilm production was enhanced in all mutants. Overall, these results indicate that in B. cenocepacia RND pumps play a wider role than just in drug resistance, influencing additional phenotypic traits important for pathogenesis.
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Affiliation(s)
- Silvia Bazzini
- Dipartimento di Genetica e Microbiologia, Università degli Studi di Pavia, Pavia, Italy
| | - Claudia Udine
- Dipartimento di Genetica e Microbiologia, Università degli Studi di Pavia, Pavia, Italy
| | - Andrea Sass
- Cardiff School of Biosciences, Cardiff University, Cardiff, Wales, United Kingdom
| | - Maria Rosalia Pasca
- Dipartimento di Genetica e Microbiologia, Università degli Studi di Pavia, Pavia, Italy
| | | | - Giovanni Emiliani
- Trees and Timber Institute – National Research Council, San Michele all'Adige, Italy
| | - Marco Fondi
- Department of Evolutionary Biology, University of Florence, Firenze, Italy
| | - Elena Perrin
- Department of Evolutionary Biology, University of Florence, Firenze, Italy
| | - Francesca Decorosi
- Dipartimento di Biotecnologie Agrarie, Università degli Studi di Firenze, Firenze, Italy
| | - Carlo Viti
- Dipartimento di Biotecnologie Agrarie, Università degli Studi di Firenze, Firenze, Italy
| | - Luciana Giovannetti
- Dipartimento di Biotecnologie Agrarie, Università degli Studi di Firenze, Firenze, Italy
| | - Livia Leoni
- Dipartimento di Biologia, Università Roma Tre, Roma, Italy
| | - Renato Fani
- Department of Evolutionary Biology, University of Florence, Firenze, Italy
| | - Giovanna Riccardi
- Dipartimento di Genetica e Microbiologia, Università degli Studi di Pavia, Pavia, Italy
| | | | - Silvia Buroni
- Dipartimento di Genetica e Microbiologia, Università degli Studi di Pavia, Pavia, Italy
- * E-mail:
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