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Nicholson TL, Waack U, Fleming DS, Chen Q, Miller LC, Merkel TJ, Stibitz S. The contribution of BvgR, RisA, and RisS to global gene regulation, intracellular cyclic-di-GMP levels, motility, and biofilm formation in Bordetella bronchiseptica. Front Microbiol 2024; 15:1305097. [PMID: 38516008 PMCID: PMC10955343 DOI: 10.3389/fmicb.2024.1305097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 02/20/2024] [Indexed: 03/23/2024] Open
Abstract
Bordetella bronchiseptica is a highly contagious respiratory bacterial veterinary pathogen. In this study the contribution of the transcriptional regulators BvgR, RisA, RisS, and the phosphorylation of RisA to global gene regulation, intracellular cyclic-di-GMP levels, motility, and biofilm formation were evaluated. Next Generation Sequencing (RNASeq) was used to differentiate the global gene regulation of both virulence-activated and virulence-repressed genes by each of these factors. The BvgAS system, along with BvgR, RisA, and the phosphorylation of RisA served in cyclic-di-GMP degradation. BvgR and unphosphorylated RisA were found to temporally regulate motility. Additionally, BvgR, RisA, and RisS were found to be required for biofilm formation.
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Affiliation(s)
- Tracy L. Nicholson
- Agricultural Research Service, USDA, National Animal Disease Center, Ames, IA, United States
| | - Ursula Waack
- Agricultural Research Service, USDA, National Animal Disease Center, Ames, IA, United States
- United States Department of Energy, Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States
| | - Damarius S. Fleming
- USDA, Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, MD, United States
| | - Qing Chen
- Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research, FDA, Silver Spring, MD, United States
| | - Laura C. Miller
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Tod J. Merkel
- Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research, FDA, Silver Spring, MD, United States
| | - Scott Stibitz
- Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research, FDA, Silver Spring, MD, United States
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2
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Badhai J, Das SK. Genomic evidence and virulence properties decipher the extra-host origin of Bordetella bronchiseptica. J Appl Microbiol 2023; 134:lxad200. [PMID: 37660236 DOI: 10.1093/jambio/lxad200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 08/12/2023] [Accepted: 08/30/2023] [Indexed: 09/04/2023]
Abstract
Until recently, members of the classical Bordetella species comprised only pathogenic bacteria that were thought to live exclusively in warm-blooded animals. The close phylogenetic relationship of Bordetella with Achromobacter and Alcaligenes, which include primarily environmental bacteria, suggests that the ancestral Bordetellae were probably free-living. Eventually, the Bordetella species evolved to infect and live within warm-blooded animals. The modern history of pathogens related to the genus Bordetella started towards the end of the 19th century when it was discovered in the infected respiratory epithelium of mammals, including humans. The first identified member was Bordetella pertussis, which causes whooping cough, a fatal disease in young children. In due course, B. bronchiseptica was recovered from the trachea and bronchi of dogs with distemper. Later, a second closely related human pathogen, B. parapertussis, was described as causing milder whooping cough. The classical Bordetellae are strictly host-associated pathogens transmitted via the host-to-host aerosol route. Recently, the B. bronchiseptica strain HT200 has been reported from a thermal spring exhibiting unique genomic features that were not previously observed in clinical strains. Therefore, it advocates that members of classical Bordetella species have evolved from environmental sources. This organism can be transmitted via environmental reservoirs as it can survive nutrient-limiting conditions and possesses a motile flagellum. This study aims to review the molecular basis of origin and virulence properties of obligate host-restricted and environmental strains of classical Bordetella.
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Affiliation(s)
- Jhasketan Badhai
- Department of Biotechnology, Institute of Life Sciences, Nalco Square, Bhubaneswar-751023, India
| | - Subrata K Das
- Department of Biotechnology, Institute of Life Sciences, Nalco Square, Bhubaneswar-751023, India
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3
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Luczo JM, Hamidou Soumana I, Reagin KL, Dihle P, Ghedin E, Klonowski KD, Harvill ET, Tompkins SM. Bordetella bronchiseptica-Mediated Interference Prevents Influenza A Virus Replication in the Murine Nasal Cavity. Microbiol Spectr 2023; 11:e0473522. [PMID: 36728413 PMCID: PMC10100957 DOI: 10.1128/spectrum.04735-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 01/09/2023] [Indexed: 02/03/2023] Open
Abstract
Colonization resistance, also known as pathogen interference, describes the ability of a colonizing microbe to interfere with the ability of an incoming microbe to establish infection, and in the case of pathogenic organisms, cause disease in a susceptible host. Furthermore, colonization-associated dysbiosis of the commensal microbiota can alter host immunocompetence and infection outcomes. Here, we investigated the role of Bordetella bronchiseptica nasal colonization and associated disruption of the nasal microbiota on the ability of influenza A virus to establish infection in the murine upper respiratory tract. Targeted sequencing of the microbial 16S rRNA gene revealed that B. bronchiseptica colonization of the nasal cavity efficiently displaced the resident commensal microbiota-the peak of this effect occurring 7 days postcolonization-and was associated with reduced influenza associated-morbidity and enhanced recovery from influenza-associated clinical disease. Anti-influenza A virus hemagglutinin-specific humoral immune responses were not affected by B. bronchiseptica colonization, although the cellular influenza PA-specific CD8+ immune responses were dampened. Notably, influenza A virus replication in the nasal cavity was negated in B. bronchiseptica-colonized mice. Collectively, this work demonstrates that B. bronchiseptica-mediated pathogen interference prevents influenza A virus replication in the murine nasal cavity. This may have direct implications for controlling influenza A virus replication in, and transmission events originating from, the upper respiratory tract. IMPORTANCE The interplay of microbial species in the upper respiratory tract is important for the ability of an incoming pathogen to establish and, in the case of pathogenic organisms, cause disease in a host. Here, we demonstrate that B. bronchiseptica efficiently colonizes and concurrently displaces the commensal nasal cavity microbiota, negating the ability of influenza A virus to establish infection. Furthermore, B. bronchiseptica colonization also reduced influenza-associated morbidity and enhanced recovery from influenza-associated disease. Collectively, this study indicates that B. bronchiseptica-mediated interference prevents influenza A virus replication in the upper respiratory tract. This result demonstrates the potential for respiratory pathogen-mediated interference to control replication and transmission dynamics of a clinically important respiratory pathogen like influenza A virus.
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Affiliation(s)
- Jasmina M. Luczo
- Center for Vaccines and Immunology, University of Georgia, Athens, Georgia, USA
- Emory-UGA Centers of Excellence for Influenza Research and Surveillance (CEIRS), Athens, Georgia, USA
| | | | - Katie L. Reagin
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Preston Dihle
- Center for Genomics and Systems Biology, New York University, New York City, New York, USA
| | - Elodie Ghedin
- Center for Genomics and Systems Biology, New York University, New York City, New York, USA
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | | | - Eric T. Harvill
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Stephen M. Tompkins
- Center for Vaccines and Immunology, University of Georgia, Athens, Georgia, USA
- Emory-UGA Centers of Excellence for Influenza Research and Surveillance (CEIRS), Athens, Georgia, USA
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
- Center for Influenza Disease and Emergence Response (CIDER), Athens, Georgia, USA
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4
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Kamanova J. Bordetella Type III Secretion Injectosome and Effector Proteins. Front Cell Infect Microbiol 2020; 10:466. [PMID: 33014891 PMCID: PMC7498569 DOI: 10.3389/fcimb.2020.00466] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 07/29/2020] [Indexed: 01/09/2023] Open
Abstract
Pertussis, also known as whooping cough, is a resurging acute respiratory disease of humans primarily caused by the Gram-negative coccobacilli Bordetella pertussis, and less commonly by the human-adapted lineage of B. parapertussis HU. The ovine-adapted lineage of B. parapertussis OV infects only sheep, while B. bronchiseptica causes chronic and often asymptomatic respiratory infections in a broad range of mammals but rarely in humans. A largely overlapping set of virulence factors inflicts the pathogenicity of these bordetellae. Their genomes also harbor a pathogenicity island, named bsc locus, that encodes components of the type III secretion injectosome, and adjacent btr locus with the type III regulatory proteins. The Bsc injectosome of bordetellae translocates the cytotoxic BteA effector protein, also referred to as BopC, into the cells of the mammalian hosts. While the role of type III secretion activity in the persistent colonization of the lower respiratory tract by B. bronchiseptica is well recognized, the functionality of the type III secretion injectosome in B. pertussis was overlooked for many years due to the adaptation of laboratory-passaged B. pertussis strains. This review highlights the current knowledge of the type III secretion system in the so-called classical Bordetella species, comprising B. pertussis, B. parapertussis, and B. bronchiseptica, and discusses its functional divergence. Comparison with other well-studied bacterial injectosomes, regulation of the type III secretion on the transcriptional and post-transcriptional level, and activities of BteA effector protein and BopN protein, homologous to the type III secretion gatekeepers, are addressed.
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Affiliation(s)
- Jana Kamanova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
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5
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Morgane Canonne A, Roels E, Menard M, Desquilbet L, Billen F, Clercx C. Clinical response to 2 protocols of aerosolized gentamicin in 46 dogs with Bordetella bronchiseptica infection (2012-2018). J Vet Intern Med 2020; 34:2078-2085. [PMID: 32790103 PMCID: PMC7517846 DOI: 10.1111/jvim.15843] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/13/2020] [Accepted: 06/13/2020] [Indexed: 11/30/2022] Open
Abstract
Background Bordetella bronchiseptica (Bb) infection commonly causes respiratory disease in dogs. Gentamicin delivered by aerosol maximizes local drug delivery without systemic absorption but clinical response to protocols remains undetermined. Objectives To compare the clinical response to 2 protocols of aerosolized delivery of gentamicin in bordetellosis. Animals Forty‐six dogs with Bb infection confirmed by culture or quantitative polymerase chain reaction on bronchoalveolar lavage. Methods Retrospective study. Administration of aerosolized gentamicin for ≥10 minutes q12h for ≥3 weeks using 4 mg/kg diluted with saline (group 1) or undiluted 5% solution (group 2). Clinical response firstly assessed after 3‐4 weeks and treatment pursued by 3‐weeks increments if cure not reached. Cure defined as absence of cough persisting at least a week after treatment interruption. Results Demographic data were similar between both groups. Clinical cure at 3‐4 weeks was more frequently observed with the use of undiluted solution (19/33 vs 3/13 dogs, P = .03) in association with a shorter median duration of treatment (4 vs 6 weeks, P = .01). Dogs from group 2 having less than 1000 cells/μL in lavage were also more likely to be cured at 3‐4 weeks than dogs with more than 1000 cells/μL [9/9 vs 10/19, P = .006] and median duration of treatment in that subgroup of animals was reduced (3 vs 5 weeks, P = .02). Conclusion and Clinical Importance Aerosolized delivery of gentamicin seems effective for inducing clinical cure in Bb infection. Clinical response appears better using undiluted 5% solution, particularly in the subgroup of dogs having less than 1000 cells/μL in lavage.
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Affiliation(s)
- Aude Morgane Canonne
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium.,Small Animals Internal Medicine Unit, National Veterinary School of Alfort, Maisons-Alfort, France
| | - Elodie Roels
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Maud Menard
- Small Animals Internal Medicine Unit, National Veterinary School of Alfort, Maisons-Alfort, France
| | - Loïc Desquilbet
- Unit of Biostatistics, National Veterinary School of Alfort, Maisons-Alfort, France
| | - Frédéric Billen
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
| | - Cécile Clercx
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
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Bayram J, Malcova I, Sinkovec L, Holubova J, Streparola G, Jurnecka D, Kucera J, Sedlacek R, Sebo P, Kamanova J. Cytotoxicity of the effector protein BteA was attenuated in Bordetella pertussis by insertion of an alanine residue. PLoS Pathog 2020; 16:e1008512. [PMID: 32776984 PMCID: PMC7446853 DOI: 10.1371/journal.ppat.1008512] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 08/20/2020] [Accepted: 06/24/2020] [Indexed: 11/30/2022] Open
Abstract
Bordetella bronchiseptica and Bordetella pertussis are closely related respiratory pathogens that evolved from a common bacterial ancestor. While B. bronchiseptica has an environmental reservoir and mostly establishes chronic infections in a broad range of mammals, B. pertussis is a human-specific pathogen causing acute pulmonary pertussis in infants and whooping cough illness in older humans. Both species employ a type III secretion system (T3SS) to inject a cytotoxic BteA effector protein into host cells. However, compared to the high BteA-mediated cytotoxicity of B. bronchiseptica, the cytotoxicity induced by B. pertussis BteA (Bp BteA) appears to be quite low and this has been attributed to the reduced T3SS gene expression in B. pertussis. We show that the presence of an alanine residue inserted at position 503 (A503) of Bp BteA accounts for its strongly attenuated cytotoxic potency. The deletion of A503 from Bp BteA greatly enhanced the cytotoxic activity of B. pertussis B1917 on mammalian HeLa cells and expression of Bp BteAΔA503 was highly toxic to Saccharomyces cerevisiae cells. Vice versa, insertion of A503 into B. bronchiseptica BteA (Bb BteA) strongly decreased its cytotoxicity to yeast and HeLa cells. Moreover, the production of Bp BteAΔA503 increased virulence of B. pertussis B1917 in the mouse model of intranasal infection (reduced LD50) but yielded less inflammatory pathology in infected mouse lungs at sublethal infectious doses. This suggests that A503 insertion in the T3SS effector Bp BteA may represent an evolutionary adaptation that fine-tunes B. pertussis virulence and host immune response. Pertussis remains the least-controlled vaccine-preventable infectious disease and the mechanisms by which Bordetella pertussis subverts defense mechanisms of human airway mucosa remain poorly understood. We found that B. pertussis had the cytotoxic activity of its type III secretion system-delivered effector BteA strongly attenuated by insertion of an alanine residue at position 503 as compared to the BteA homologue of the animal pathogen B. bronchiseptica. This functional adaptation reduced the capacity of B. pertussis to suppress host inflammatory response and may contribute to an acute course of the pulmonary form of human infant pertussis.
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Affiliation(s)
- Jan Bayram
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ivana Malcova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Larisa Sinkovec
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jana Holubova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Gaia Streparola
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Vestec, Czech Republic
| | - David Jurnecka
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Kucera
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Vestec, Czech Republic
| | - Radislav Sedlacek
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Vestec, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jana Kamanova
- Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
- * E-mail:
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7
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Analysis of the lung microbiota in dogs with Bordetella bronchiseptica infection and correlation with culture and quantitative polymerase chain reaction. Vet Res 2020; 51:46. [PMID: 32209128 PMCID: PMC7092585 DOI: 10.1186/s13567-020-00769-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 03/02/2020] [Indexed: 12/29/2022] Open
Abstract
Infection with Bordetella bronchiseptica (Bb), a pathogen involved in canine infectious respiratory disease complex, can be confirmed using culture or qPCR. Studies about the canine lung microbiota (LM) are recent, sparse, and only one paper has been published in canine lung infection. In this study, we aimed to compare the LM between Bb infected and healthy dogs, and to correlate sequencing with culture and qPCR results. Twenty Bb infected dogs diagnosed either by qPCR and/or culture and 4 healthy dogs were included. qPCR for Mycoplasma cynos (Mc) were also available in 18 diseased and all healthy dogs. Sequencing results, obtained from bronchoalveolar lavage fluid after DNA extraction, PCR targeting the V1–V3 region of the 16S rDNA and sequencing, showed the presence of Bb in all diseased dogs, about half being co-infected with Mc. In diseased compared with healthy dogs, the β-diversity changed (P = 0.0024); bacterial richness and α-diversity were lower (P = 0.012 and 0.0061), and bacterial load higher (P = 0.004). Bb qPCR classes and culture results correlated with the abundance of Bb (r = 0.71, P < 0.001 and r = 0.70, P = 0.0022). Mc qPCR classes also correlated with the abundance of Mc (r = 0.73, P < 0.001). Bb infection induced lung dysbiosis, characterized by high bacterial load, low richness and diversity and increased abundance of Bb, compared with healthy dogs. Sequencing results highly correlate with qPCR and culture results showing that sequencing can be reliable to identify microorganisms involved in lung infectious diseases.
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8
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Gestal MC, Howard LK, Dewan K, Johnson HM, Barbier M, Bryant C, Soumana IH, Rivera I, Linz B, Blas-Machado U, Harvill ET. Enhancement of immune response against Bordetella spp. by disrupting immunomodulation. Sci Rep 2019; 9:20261. [PMID: 31889098 PMCID: PMC6937331 DOI: 10.1038/s41598-019-56652-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 12/12/2019] [Indexed: 12/27/2022] Open
Abstract
Well-adapted pathogens must evade clearance by the host immune system and the study of how they do this has revealed myriad complex strategies and mechanisms. Classical bordetellae are very closely related subspecies that are known to modulate adaptive immunity in a variety of ways, permitting them to either persist for life or repeatedly infect the same host. Exploring the hypothesis that exposure to immune cells would cause bordetellae to induce expression of important immunomodulatory mechanisms, we identified a putative regulator of an immunomodulatory pathway. The deletion of btrS in B. bronchiseptica did not affect colonization or initial growth in the respiratory tract of mice, its natural host, but did increase activation of the inflammasome pathway, and recruitment of inflammatory cells. The mutant lacking btrS recruited many more B and T cells into the lungs, where they rapidly formed highly organized and distinctive Bronchial Associated Lymphoid Tissue (BALT) not induced by any wild type Bordetella species, and a much more rapid and strong antibody response than observed with any of these species. Immunity induced by the mutant was measurably more robust in all respiratory organs, providing completely sterilizing immunity that protected against challenge infections for many months. Moreover, the mutant induced sterilizing immunity against infection with other classical bordetellae, including B. pertussis and B. parapertussis, something the current vaccines do not provide. These findings reveal profound immunomodulation by bordetellae and demonstrate that by disrupting it much more robust protective immunity can be generated, providing a pathway to greatly improve vaccines and preventive treatments against these important pathogens.
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Affiliation(s)
- Monica C Gestal
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America.
| | - Laura K Howard
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Kalyan Dewan
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Hannah M Johnson
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Mariette Barbier
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, WV, United States of America
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, United States of America
| | - Clare Bryant
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, United Kingdom
| | - Illiassou Hamidou Soumana
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Israel Rivera
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Bodo Linz
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Uriel Blas-Machado
- Department of Pathology, Athens Veterinary Diagnostic Laboratory, University of Georgia, Athens, Georgia, United States of America
| | - Eric T Harvill
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America.
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Abstract
In vitro growth conditions for bacteria do not fully recapitulate the host environment. RNA sequencing transcriptome analysis allows for the characterization of the infection gene expression profiles of pathogens in complex environments. Isolation of the pathogen from infected tissues is critical because of the large amounts of host RNA present in crude lysates of infected organs. A filtration method was developed that enabled enrichment of the pathogen RNA for RNA-seq analysis. The resulting data describe the “infection transcriptome” of B. pertussis in the murine lung. This strategy can be utilized for pathogens in other hosts and, thus, expand our knowledge of what bacteria express during infection. Bordetella pertussis causes the disease whooping cough through coordinated control of virulence factors by the Bordetella virulence gene system. Microarrays and, more recently, RNA sequencing (RNA-seq) have been used to describe in vitro gene expression profiles of B. pertussis and other pathogens. In previous studies, we have analyzed the in vitro gene expression profiles of B. pertussis, and we hypothesize that the infection transcriptome profile in vivo is significantly different from that under laboratory growth conditions. To study the infection transcriptome of B. pertussis, we developed a simple filtration technique for isolation of bacteria from infected lungs. The work flow involves filtering the bacteria out of the lung homogenate using a 5-μm-pore-size syringe filter. The captured bacteria are then lysed to isolate RNA for Illumina library preparation and RNA-seq analysis. Upon comparing the in vitro and in vivo gene expression profiles, we identified 351 and 255 genes as activated and repressed, respectively, during murine lung infection. As expected, numerous genes associated with virulent-phase growth were activated in the murine host, including pertussis toxin (PT), the PT secretion apparatus, and the type III secretion system. A significant number of genes encoding iron acquisition and heme uptake proteins were highly expressed during infection, supporting iron acquisition as critical for B. pertussis survival in vivo. Numerous metabolic genes were repressed during infection. Overall, these data shed light on the gene expression profile of B. pertussis during infection, and this method will facilitate efforts to understand how this pathogen causes infection. IMPORTANCEIn vitro growth conditions for bacteria do not fully recapitulate the host environment. RNA sequencing transcriptome analysis allows for the characterization of the infection gene expression profiles of pathogens in complex environments. Isolation of the pathogen from infected tissues is critical because of the large amounts of host RNA present in crude lysates of infected organs. A filtration method was developed that enabled enrichment of the pathogen RNA for RNA-seq analysis. The resulting data describe the “infection transcriptome” of B. pertussis in the murine lung. This strategy can be utilized for pathogens in other hosts and, thus, expand our knowledge of what bacteria express during infection.
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10
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Gestal MC, Rivera I, Howard LK, Dewan KK, Soumana IH, Dedloff M, Nicholson TL, Linz B, Harvill ET. Blood or Serum Exposure Induce Global Transcriptional Changes, Altered Antigenic Profile, and Increased Cytotoxicity by Classical Bordetellae. Front Microbiol 2018; 9:1969. [PMID: 30245672 PMCID: PMC6137168 DOI: 10.3389/fmicb.2018.01969] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 08/03/2018] [Indexed: 01/01/2023] Open
Abstract
The classical bordetellae sense and respond to a variety of environments outside and within their mammalian hosts. By causing inflammation and tissue damage, we reasoned that bordetellae are likely to encounter components of blood and/or serum during the course of a respiratory infection, and that detecting and responding to these would be advantageous. Therefore, we hypothesized that classical bordetellae have the ability to sense and respond to blood or serum. Blood or serum exposure resulted in substantial transcriptional changes in Bordetella bronchiseptica, including enhanced expression of many virulence-associated genes. Exposure to blood or serum additionally elicited production of multiple antigens not otherwise detectable, and led to increased bacterial cytotoxicity against macrophages. Transcriptional responses to blood/serum were observed in a Bvg- phase-locked mutant, indicating that the response is not solely dependent on a functional BvgAS system. Similar transcriptional responses to blood/serum were observed for the other classical bordetellae, Bordetella pertussis and Bordetella parapertussis. These data suggest the classical bordetellae respond to signals present in blood and serum by changing their behavior in ways that likely contribute to their remarkable success, via effects on pathogenesis, persistence and/or transmission between hosts.
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Affiliation(s)
- Monica C Gestal
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Israel Rivera
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Laura K Howard
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Kalyan K Dewan
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Illiassou Hamidou Soumana
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Margaret Dedloff
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | | | - Bodo Linz
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Eric T Harvill
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
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11
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Jeron A, Boehme JD, Volckmar J, Gereke M, Yevsa T, Geffers R, Guzmán CA, Schreiber J, Stegemann-Koniszewski S, Bruder D. Respiratory Bordetella bronchiseptica Carriage is Associated with Broad Phenotypic Alterations of Peripheral CD4⁺CD25⁺ T Cells and Differentially Affects Immune Responses to Secondary Non-Infectious and Infectious Stimuli in Mice. Int J Mol Sci 2018; 19:E2602. [PMID: 30200513 PMCID: PMC6165163 DOI: 10.3390/ijms19092602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 08/03/2018] [Accepted: 08/28/2018] [Indexed: 01/05/2023] Open
Abstract
The respiratory tract is constantly exposed to the environment and displays a favorable niche for colonizing microorganisms. However, the effects of respiratory bacterial carriage on the immune system and its implications for secondary responses remain largely unclear. We have employed respiratory carriage with Bordetella bronchiseptica as the underlying model to comprehensively address effects on subsequent immune responses. Carriage was associated with the stimulation of Bordetella-specific CD4⁺, CD8⁺, and CD4⁺CD25⁺Foxp3⁺ T cell responses, and broad transcriptional activation was observed in CD4⁺CD25⁺ T cells. Importantly, transfer of leukocytes from carriers to acutely B. bronchiseptica infected mice, resulted in a significantly increased bacterial burden in the recipient's upper respiratory tract. In contrast, we found that respiratory B. bronchiseptica carriage resulted in a significant benefit for the host in systemic infection with Listeria monocytogenes. Adaptive responses to vaccination and influenza A virus infection, were unaffected by B. bronchiseptica carriage. These data showed that there were significant immune modulatory processes triggered by B. bronchiseptica carriage, that differentially affect subsequent immune responses. Therefore, our results demonstrated the complexity of immune regulation induced by respiratory bacterial carriage, which can be beneficial or detrimental to the host, depending on the pathogen and the considered compartment.
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Affiliation(s)
- Andreas Jeron
- Infection Immunology Group, Institute of Medical Microbiology, Infection Control and Prevention, Health Campus Immunology, Infectiology and Inflammation, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany.
- Immune Regulation Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.
| | - Julia D Boehme
- Infection Immunology Group, Institute of Medical Microbiology, Infection Control and Prevention, Health Campus Immunology, Infectiology and Inflammation, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany.
- Immune Regulation Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.
| | - Julia Volckmar
- Infection Immunology Group, Institute of Medical Microbiology, Infection Control and Prevention, Health Campus Immunology, Infectiology and Inflammation, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany.
- Immune Regulation Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.
| | - Marcus Gereke
- Infection Immunology Group, Institute of Medical Microbiology, Infection Control and Prevention, Health Campus Immunology, Infectiology and Inflammation, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany.
- Immune Regulation Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.
| | - Tetyana Yevsa
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.
| | - Robert Geffers
- Genome Analytics Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.
| | - Carlos A Guzmán
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.
| | - Jens Schreiber
- Experimental Pneumology, University Hospital for Pneumology, Health Campus Immunology, Infectiology and Inflammation, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany.
| | - Sabine Stegemann-Koniszewski
- Infection Immunology Group, Institute of Medical Microbiology, Infection Control and Prevention, Health Campus Immunology, Infectiology and Inflammation, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany.
- Immune Regulation Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.
- Experimental Pneumology, University Hospital for Pneumology, Health Campus Immunology, Infectiology and Inflammation, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany.
| | - Dunja Bruder
- Infection Immunology Group, Institute of Medical Microbiology, Infection Control and Prevention, Health Campus Immunology, Infectiology and Inflammation, Otto-von-Guericke University Magdeburg, 39120 Magdeburg, Germany.
- Immune Regulation Group, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.
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LOONG SK, CHE-MAT-SERI NAA, ABDULRAZAK O, DOUADI B, AHMAD-NASRAH SN, JOHARI J, MOHD-ZAIN SN, ABUBAKAR S. Recovery of Bordetella bronchiseptica sequence type 82 and B. pseudohinzii from urban rats in Terengganu, Malaysia. J Vet Med Sci 2018; 80:77-84. [PMID: 29237995 PMCID: PMC5797863 DOI: 10.1292/jvms.17-0218] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 11/01/2017] [Indexed: 12/22/2022] Open
Abstract
Rodents have historically been associated with zoonotic pandemics that claimed the lives of large human populations. Appropriate pathogen surveillance initiatives could contribute to early detection of zoonotic infections to prevent future outbreaks. Bordetella species are bacteria known to cause mild to severe respiratory disease in mammals and, some have been described to infect, colonize and spread in rodents. There is a lack of information on the population diversity of bordetellae among Malaysian wild rodents. Here, bordetellae recovered from lung tissues of wild rats were genotypically characterized using 16S rDNA sequencing, MLST and nrdA typing. A novel B. bronchiseptica ST82, closely related to other human-derived isolates, was discovered in three wild rats (n=3) from Terengganu (5.3333° N, 103.1500° E). B. pseudohinzii, a recently identified laboratory mice inhabitant, was also recovered from one rat (n=1). Both bordetellae displayed identical antimicrobial resistance profiles, indicating the close phylogenetic association between them. Genotyping using the 765-bp nrdA locus was shown to be compatible with the MLST-based phylogeny, with the added advantage of being able to genotype non-classical bordetellae. The recovery of B. pseudohinzii from wild rat implied that this bordetellae has a wider host range than previously thought. The findings from this study suggest that bordetellae surveillance among wild rats in Malaysia has to be continued and expanded to other states to ensure early identification of species capable of causing public health disorder.
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Affiliation(s)
- Shih Keng LOONG
- Tropical Infectious Diseases Research & Education Centre, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Nurul-Asma-Anati CHE-MAT-SERI
- Tropical Infectious Diseases Research & Education Centre, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Osama ABDULRAZAK
- Microbial Evolutionary Dynamics Research Group, Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
| | - Benacer DOUADI
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Siti-Noraisah AHMAD-NASRAH
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Jefree JOHARI
- Tropical Infectious Diseases Research & Education Centre, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Siti-Nursheena MOHD-ZAIN
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Sazaly ABUBAKAR
- Tropical Infectious Diseases Research & Education Centre, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
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The Bordetella Bps Polysaccharide Is Required for Biofilm Formation and Enhances Survival in the Lower Respiratory Tract of Swine. Infect Immun 2017; 85:IAI.00261-17. [PMID: 28559403 DOI: 10.1128/iai.00261-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 05/18/2017] [Indexed: 12/21/2022] Open
Abstract
Bordetella bronchiseptica is pervasive in swine populations and plays multiple roles in respiratory disease. Additionally, B. bronchiseptica is capable of establishing long-term or chronic infections in swine. Bacterial biofilms are increasingly recognized as important contributors to chronic bacterial infections. Recently the polysaccharide locus bpsABCD has been demonstrated to serve a critical role in the development of mature biofilms formed by the sequenced laboratory strain of B. bronchiseptica We hypothesized that swine isolates would also have the ability to form mature biofilms and the bpsABCD locus would serve a key role in this process. A mutant containing an in-frame deletion of the bpsABCD structural genes was constructed in a wild-type swine isolate and found to be negative for poly-N-acetylglucosamine (PNAG)-like material by immunoblot assay. Further, the bpsABCD locus was found to be required for the development and maintenance of the three-dimensional structures under continuous-flow conditions. To investigate the contribution of the bpsABCD locus to the pathogenesis of B. bronchiseptica in swine, the KM22Δbps mutant was compared to the wild-type swine isolate for the ability to colonize and cause disease in pigs. The bpsABCD locus was found to not be required for persistence in the upper respiratory tract of swine. Additionally, the bpsABCD locus did not affect the development of anti-Bordetella humoral immunity, did not contribute to disease severity, and did not mediate protection from complement-mediated killing. However, the bpsABCD locus was found to enhance survival in the lower respiratory tract of swine.
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Albumin, in the Presence of Calcium, Elicits a Massive Increase in Extracellular Bordetella Adenylate Cyclase Toxin. Infect Immun 2017; 85:IAI.00198-17. [PMID: 28396321 DOI: 10.1128/iai.00198-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 04/02/2017] [Indexed: 12/14/2022] Open
Abstract
Pertussis (whooping cough), caused by Bordetella pertussis, is resurging in the United States and worldwide. Adenylate cyclase toxin (ACT) is a critical factor in establishing infection with B. pertussis and acts by specifically inhibiting the response of myeloid leukocytes to the pathogen. We report here that serum components, as discovered during growth in fetal bovine serum (FBS), elicit a robust increase in the amount of ACT, and ≥90% of this ACT is localized to the supernatant, unlike growth without FBS, in which ≥90% is associated with the bacterium. We have found that albumin, in the presence of physiological concentrations of calcium, acts specifically to enhance the amount of ACT and its localization to the supernatant. Respiratory secretions, which contain albumin, promote an increase in amount and localization of active ACT that is comparable to that elicited by serum and albumin. The response to albumin is not mediated through regulation of ACT at the transcriptional level or activation of the Bvg two-component system. As further illustration of the specificity of this phenomenon, serum collected from mice that lack albumin does not stimulate an increase in ACT. These data, demonstrating that albumin and calcium act synergistically in the host environment to increase production and release of ACT, strongly suggest that this phenomenon reflects a novel host-pathogen interaction that is central to infection with B. pertussis and other Bordetella species.
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Bordetella bronchiseptica exploits the complex life cycle of Dictyostelium discoideum as an amplifying transmission vector. PLoS Biol 2017; 15:e2000420. [PMID: 28403138 PMCID: PMC5389573 DOI: 10.1371/journal.pbio.2000420] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 03/14/2017] [Indexed: 12/02/2022] Open
Abstract
Multiple lines of evidence suggest that Bordetella species have a significant life stage outside of the mammalian respiratory tract that has yet to be defined. The Bordetella virulence gene (BvgAS) two-component system, a paradigm for a global virulence regulon, controls the expression of many “virulence factors” expressed in the Bvg positive (Bvg+) phase that are necessary for successful respiratory tract infection. A similarly large set of highly conserved genes are expressed under Bvg negative (Bvg-) phase growth conditions; however, these appear to be primarily expressed outside of the host and are thus hypothesized to be important in an undefined extrahost reservoir. Here, we show that Bvg- phase genes are involved in the ability of Bordetella bronchiseptica to grow and disseminate via the complex life cycle of the amoeba Dictyostelium discoideum. Unlike bacteria that serve as an amoeba food source, B. bronchiseptica evades amoeba predation, survives within the amoeba for extended periods of time, incorporates itself into the amoeba sori, and disseminates along with the amoeba. Remarkably, B. bronchiseptica continues to be transferred with the amoeba for months, through multiple life cycles of amoebae grown on the lawns of other bacteria, thus demonstrating a stable relationship that allows B. bronchiseptica to expand and disperse geographically via the D. discoideum life cycle. Furthermore, B. bronchiseptica within the sori can efficiently infect mice, indicating that amoebae may represent an environmental vector within which pathogenic bordetellae expand and disseminate to encounter new mammalian hosts. These data identify amoebae as potential environmental reservoirs as well as amplifying and disseminating vectors for B. bronchiseptica and reveal an important role for the Bvg- phase in these interactions. Bordetella species are infectious bacterial respiratory pathogens of a range of animals, including humans. Bordetellae grow in two phenotypically distinct “phases,” each specifically expressing a large set of genes. The Bvg+ phase is primarily associated with respiratory tract infection (RTI) and has been well studied. The similarly large set of genes specifically expressed in the Bvg- phase is poorly understood but has been proposed to be involved in some undefined environmental niche. Recently, we reported the presence of Bordetella species in many soil and water sources, indicating extensive exposure to predators. Herein, we show that the Bvg- phase mediates B. bronchiseptica interactions with the common soil predator D. discoideum. Surprisingly, the bacterium not only can evade predation but can propagate and disseminate via the complex developmental process of D. discoideum. After multiple passages and over a million-fold expansion in association with D. discoideum, B. bronchiseptica retained the ability to efficiently colonize mice. The conservation of the genes involved in these two distinct phases raises the possibility of potential environmental sources for the frequently unexplained outbreaks of diseases caused by this and other Bordetella species.
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17
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Type Six Secretion System of Bordetella bronchiseptica and Adaptive Immune Components Limit Intracellular Survival During Infection. PLoS One 2015; 10:e0140743. [PMID: 26485303 PMCID: PMC4618060 DOI: 10.1371/journal.pone.0140743] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 09/30/2015] [Indexed: 11/19/2022] Open
Abstract
The Type Six Secretion System (T6SS) is required for Bordetella bronchiseptica cytotoxicity, cytokine modulation, infection, and persistence. However, one-third of recently sequenced Bordetella bronchiseptica strains of the predominantly human-associated Complex IV have lost their T6SS through gene deletion or degradation. Since most human B. bronchiseptica infections occur in immunocompromised patients, we determine here whether loss of Type Six Secretion is beneficial to B. bronchiseptica during infection of immunocompromised mice. Infection of mice lacking adaptive immunity (Rag1-/- mice) with a T6SS-deficient mutant results in a hypervirulent phenotype that is characterized by high numbers of intracellular bacteria in systemic organs. In contrast, wild-type B. bronchiseptica kill their eukaryotic cellular hosts via a T6SS-dependent mechanism that prevents survival in systemic organs. High numbers of intracellular bacteria recovered from immunodeficient mice but only low numbers from wild-type mice demonstrates that B. bronchiseptica survival in an intracellular niche is limited by B and T cell responses. Understanding the nature of intracellular survival during infection, and its effects on the generation and function of the host immune response, are important to contain and control the spread of Bordetella-caused disease.
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Park J, Zhang Y, Chen C, Dudley EG, Harvill ET. Diversity of secretion systems associated with virulence characteristics of the classical bordetellae. MICROBIOLOGY-SGM 2015; 161:2328-40. [PMID: 26459829 DOI: 10.1099/mic.0.000197] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Secretion systems are key virulence factors, modulating interactions between pathogens and the host's immune response. Six potential secretion systems (types 1-6; T1SS-T6SS) have been discussed in classical bordetellae, respiratory commensals/pathogens of mammals. The prototypical Bordetella bronchiseptica strain RB50 genome seems to contain all six systems, whilst two human-restricted subspecies, Bordetella parapertussis and Bordetella pertussis, have lost different subsets of these. This implicates secretion systems in the divergent evolutionary histories that have led to their success in different niches. Based on our previous work demonstrating that changes in secretion systems are associated with virulence characteristics, we hypothesized there would be substantial divergence of the loci encoding each amongst sequenced strains. Here, we describe extensive differences in secretion system loci; 10 of the 11 sequenced strains had lost subsets of genes or one entire secretion system locus. These loci contained genes homologous to those present in the respective loci in distantly related organisms, as well as genes unique to bordetellae, suggesting novel and/or auxiliary functions. The high degree of conservation of the T3SS locus, a complex machine with interdependent parts that must be conserved, stands in dramatic contrast to repeated loss of T5aSS 'autotransporters', which function as an autonomous unit. This comparative analysis provided insights into critical aspects of each pathogen's adaptation to its different niche, and the relative contributions of recombination, mutation and horizontal gene transfer. In addition, the relative conservation of various secretion systems is an important consideration in the ongoing search for more highly conserved protective antigens for the next generation of pertussis vaccines.
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Affiliation(s)
- Jihye Park
- 1 Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA, USA 2 Graduate Program in Bioinformatics and Genomics, Pennsylvania State University, University Park, PA, USA
| | - Ying Zhang
- 1 Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA, USA
| | - Chun Chen
- 3 Department of Food Science, Pennsylvania State University, University Park, PA, USA
| | - Edward G Dudley
- 3 Department of Food Science, Pennsylvania State University, University Park, PA, USA
| | - Eric T Harvill
- 1 Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA, USA 4 Singapore Centre on Environmental Life Sciences Engineering, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
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Register KB, Ivanov YV, Harvill ET, Davison N, Foster G. Novel, host-restricted genotypes of Bordetella bronchiseptica associated with phocine respiratory tract isolates. MICROBIOLOGY (READING, ENGLAND) 2015; 161:580-92. [PMID: 25627438 PMCID: PMC4811649 DOI: 10.1099/mic.0.000035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 01/09/2015] [Indexed: 11/18/2022]
Abstract
During a succession of phocine morbillivirus outbreaks spanning the past 25 years, Bordetella bronchiseptica was identified as a frequent secondary invader and cause of death. The goal of this study was to evaluate genetic diversity and the molecular basis for host specificity among seal isolates from these outbreaks. MLST and PvuII ribotyping of 54 isolates from Scottish, English or Danish coasts of the Atlantic or North Sea revealed a single, host-restricted genotype. A single, novel genotype, unique from that of the Atlantic and North Sea isolates, was found in isolates from an outbreak in the Caspian Sea. Phylogenetic analysis based either on MLST sequence, ribotype patterns or genome-wide SNPs consistently placed both seal-specific genotypes within the same major clade but indicates a distinct evolutionary history for each. An additional isolate from the intestinal tract of a seal on the south-west coast of England has a genotype otherwise found in rabbit, guinea pig and pig isolates. To investigate the molecular basis for host specificity, DNA and predicted protein sequences of virulence genes that mediate host interactions were used in comparisons between a North Sea isolate, a Caspian Sea isolate and each of their closest relatives as inferred from genome-wide SNP analysis. Despite their phylogenetic divergence, fewer nucleotide and amino acid substitutions were found in comparisons of the two seal isolates than in comparisons with closely related strains. These data indicate isolates of B. bronchiseptica associated with respiratory disease in seals comprise unique, host-adapted and highly clonal populations.
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Affiliation(s)
- Karen B Register
- USDA, Agricultural Research Service, National Animal Disease Center, Ruminant Diseases and Immunology Research Unit, 1920 Dayton Avenue, Ames, IA 50010, USA
| | - Yury V Ivanov
- The Pennsylvania State University, Department of Veterinary and Biomedical Sciences, W-213 Millennium Science Complex, University Park, PA 16802, USA
| | - Eric T Harvill
- The Pennsylvania State University, Department of Veterinary and Biomedical Sciences, W-213 Millennium Science Complex, University Park, PA 16802, USA
| | - Nick Davison
- Scottish Marine Animal Stranding Scheme SAC Consulting Veterinary Services, Drummondhill, Stratherrick Road, Inverness IV2 4JZ, UK
| | - Geoffrey Foster
- Scottish Marine Animal Stranding Scheme SAC Consulting Veterinary Services, Drummondhill, Stratherrick Road, Inverness IV2 4JZ, UK
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Comparative analyses of a cystic fibrosis isolate of Bordetella bronchiseptica reveal differences in important pathogenic phenotypes. Infect Immun 2014; 82:1627-37. [PMID: 24470470 DOI: 10.1128/iai.01453-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Bordetella bronchiseptica is a Gram-negative bacterium that infects and causes disease in a wide variety of animals. B. bronchiseptica also infects humans, thereby demonstrating zoonotic transmission. An extensive characterization of human B. bronchiseptica isolates is needed to better understand the distinct genetic and phenotypic traits associated with these zoonotic transmission events. Using whole-genome transcriptome and CGH analysis, we report that a B. bronchiseptica cystic fibrosis isolate, T44625, contains a distinct genomic content of virulence-associated genes and differentially expresses these genes compared to the sequenced model laboratory strain RB50, a rabbit isolate. The differential gene expression pattern correlated with unique phenotypes exhibited by T44625, which included lower motility, increased aggregation, hyperbiofilm formation, and an increased in vitro capacity to adhere to respiratory epithelial cells. Using a mouse intranasal infection model, we found that although defective in establishing high bacterial burdens early during the infection process, T44625 persisted efficiently in the mouse nose. By documenting the unique genomic and phenotypic attributes of T44625, this report provides a blueprint for understanding the successful zoonotic potential of B. bronchiseptica and other zoonotic bacteria.
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The Bordetella bronchiseptica type III secretion system is required for persistence and disease severity but not transmission in swine. Infect Immun 2013; 82:1092-103. [PMID: 24366249 DOI: 10.1128/iai.01115-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Bordetella bronchiseptica is pervasive in swine populations and plays multiple roles in respiratory disease. Most studies addressing virulence factors of B. bronchiseptica utilize isolates derived from hosts other than pigs in conjunction with rodent infection models. Based on previous in vivo mouse studies, we hypothesized that the B. bronchiseptica type III secretion system (T3SS) would be required for maximal disease severity and persistence in the swine lower respiratory tract. To examine the contribution of the T3SS to the pathogenesis of B. bronchiseptica in swine, we compared the abilities of a virulent swine isolate and an isogenic T3SS mutant to colonize, cause disease, and be transmitted from host to host. We found that the T3SS is required for maximal persistence throughout the lower swine respiratory tract and contributed significantly to the development of nasal lesions and pneumonia. However, the T3SS mutant and the wild-type parent are equally capable of transmission among swine by both direct and indirect routes, demonstrating that transmission can occur even with attenuated disease. Our data further suggest that the T3SS skews the adaptive immune response in swine by hindering the development of serum anti-Bordetella antibody levels and inducing an interleukin-10 (IL-10) cell-mediated response, likely contributing to the persistence of B. bronchiseptica in the respiratory tract. Overall, our results demonstrate that the Bordetella T3SS is required for maximal persistence and disease severity in pigs, but not for transmission.
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Hegerle N, Rayat L, Dore G, Zidane N, Bedouelle H, Guiso N. In-vitro and in-vivo analysis of the production of the Bordetella type three secretion system effector A in Bordetella pertussis, Bordetella parapertussis and Bordetella bronchiseptica. Microbes Infect 2013; 15:399-408. [DOI: 10.1016/j.micinf.2013.02.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 02/20/2013] [Accepted: 02/20/2013] [Indexed: 01/11/2023]
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Nicholson TL, Conover MS, Deora R. Transcriptome profiling reveals stage-specific production and requirement of flagella during biofilm development in Bordetella bronchiseptica. PLoS One 2012; 7:e49166. [PMID: 23152870 PMCID: PMC3495763 DOI: 10.1371/journal.pone.0049166] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 10/09/2012] [Indexed: 11/25/2022] Open
Abstract
We have used microarray analysis to study the transcriptome of the bacterial pathogen Bordetella bronchiseptica over the course of five time points representing distinct stages of biofilm development. The results suggest that B. bronchiseptica undergoes a coordinately regulated gene expression program similar to a bacterial developmental process. Expression and subsequent production of the genes encoding flagella, a classical Bvg− phase phenotype, occurs and is under tight regulatory control during B. bronchiseptica biofilm development. Using mutational analysis, we demonstrate that flagella production at the appropriate stage of biofilm development, i.e. production early subsequently followed by repression, is required for robust biofilm formation and maturation. We also demonstrate that flagella are necessary and enhance the initial cell-surface interactions, thereby providing mechanistic information on the initial stages of biofilm development for B. bronchiseptica. Biofilm formation by B. bronchiseptica involves the production of both Bvg-activated and Bvg-repressed factors followed by the repression of factors that inhibit formation of mature biofilms.
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Affiliation(s)
- Tracy L. Nicholson
- National Animal Disease Center, Agricultural Research Service, USDA, Ames, Iowa, United States of America
- * E-mail: (RD); (TLN)
| | - Matt S. Conover
- Program in Molecular Genetics, Wake Forest University Health Sciences, Winston-Salem, North Carolina, United States of America
| | - Rajendar Deora
- Program in Molecular Genetics, Wake Forest University Health Sciences, Winston-Salem, North Carolina, United States of America
- Department of Microbiology and Immunology, Wake Forest University Health Sciences, Winston-Salem, North Carolina, United States of America
- * E-mail: (RD); (TLN)
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Hester SE, Lui M, Nicholson T, Nowacki D, Harvill ET. Identification of a CO2 responsive regulon in Bordetella. PLoS One 2012; 7:e47635. [PMID: 23112828 PMCID: PMC3480411 DOI: 10.1371/journal.pone.0047635] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 09/19/2012] [Indexed: 01/13/2023] Open
Abstract
Sensing the environment allows pathogenic bacteria to coordinately regulate gene expression to maximize survival within or outside of a host. Here we show that Bordetella species regulate virulence factor expression in response to carbon dioxide levels that mimic in vivo conditions within the respiratory tract. We found strains of Bordetella bronchiseptica that did not produce adenylate cyclase toxin (ACT) when grown in liquid or solid media with ambient air aeration, but produced ACT and additional antigens when grown in air supplemented to 5% CO(2). Transcriptome analysis and quantitative real time-PCR analysis revealed that strain 761, as well as strain RB50, increased transcription of genes encoding ACT, filamentous hemagglutinin (FHA), pertactin, fimbriae and the type III secretion system in 5% CO(2) conditions, relative to ambient air. Furthermore, transcription of cyaA and fhaB in response to 5% CO(2) was increased even in the absence of BvgS. In vitro analysis also revealed increases in cytotoxicity and adherence when strains were grown in 5% CO(2). The human pathogens B. pertussis and B. parapertussis also increased transcription of several virulence factors when grown in 5% CO(2), indicating that this response is conserved among the classical bordetellae. Together, our data indicate that Bordetella species can sense and respond to physiologically relevant changes in CO(2) concentrations by regulating virulence factors important for colonization, persistence and evasion of the host immune response.
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Affiliation(s)
- Sara E. Hester
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Graduate Program in Biochemistry, Microbiology, and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Minghsun Lui
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at UCLA, University of California Los Angeles, Los Angeles, California, United States of America
| | - Tracy Nicholson
- National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, Iowa, United State of America
| | - Daryl Nowacki
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Graduate Program in Biochemistry, Microbiology, and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Eric T. Harvill
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
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A Type VI secretion system encoding locus is required for Bordetella bronchiseptica immunomodulation and persistence in vivo. PLoS One 2012; 7:e45892. [PMID: 23071529 PMCID: PMC3470547 DOI: 10.1371/journal.pone.0045892] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 08/27/2012] [Indexed: 11/19/2022] Open
Abstract
Type VI Secretion Systems (T6SSs) have been identified in numerous Gram-negative pathogens, but the lack of a natural host infection model has limited analysis of T6SS contributions to infection and pathogenesis. Here, we describe disruption of a gene within locus encoding a putative T6SS in Bordetella bronchiseptica strain RB50, a respiratory pathogen that circulates in a broad range of mammals, including humans, domestic animals, and mice. The 26 gene locus encoding the B. bronchiseptica T6SS contains apparent orthologs to all known core genes and possesses thirteen novel genes. By generating an in frame deletion of clpV, which encodes a putative ATPase required for some T6SS-dependent protein secretion, we observe that ClpV contributes to in vitro macrophage cytotoxicity while inducing several eukaryotic proteins associated with apoptosis. Additionally, ClpV is required for induction of IL-1β, IL-6, IL-17, and IL-10 production in J774 macrophages infected with RB50. During infections in wild type mice, we determined that ClpV contributes to altered cytokine production, increased pathology, delayed lower respiratory tract clearance, and long term nasal cavity persistence. Together, these results reveal a natural host infection system in which to interrogate T6SS contributions to immunomodulation and pathogenesis.
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Park J, Zhang Y, Buboltz AM, Zhang X, Schuster SC, Ahuja U, Liu M, Miller JF, Sebaihia M, Bentley SD, Parkhill J, Harvill ET. Comparative genomics of the classical Bordetella subspecies: the evolution and exchange of virulence-associated diversity amongst closely related pathogens. BMC Genomics 2012; 13:545. [PMID: 23051057 PMCID: PMC3533505 DOI: 10.1186/1471-2164-13-545] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 09/21/2012] [Indexed: 12/04/2022] Open
Abstract
Background The classical Bordetella subspecies are phylogenetically closely related, yet differ in some of the most interesting and important characteristics of pathogens, such as host range, virulence and persistence. The compelling picture from previous comparisons of the three sequenced genomes was of genome degradation, with substantial loss of genome content (up to 24%) associated with adaptation to humans. Results For a more comprehensive picture of lineage evolution, we employed comparative genomic and phylogenomic analyses using seven additional diverse, newly sequenced Bordetella isolates. Genome-wide single nucleotide polymorphism (SNP) analysis supports a reevaluation of the phylogenetic relationships between the classical Bordetella subspecies, and suggests a closer link between ovine and human B. parapertussis lineages than has been previously proposed. Comparative analyses of genome content revealed that only 50% of the pan-genome is conserved in all strains, reflecting substantial diversity of genome content in these closely related pathogens that may relate to their different host ranges, virulence and persistence characteristics. Strikingly, these analyses suggest possible horizontal gene transfer (HGT) events in multiple loci encoding virulence factors, including O-antigen and pertussis toxin (Ptx). Segments of the pertussis toxin locus (ptx) and its secretion system locus (ptl) appear to have been acquired by the classical Bordetella subspecies and are divergent in different lineages, suggesting functional divergence in the classical Bordetellae. Conclusions Together, these observations, especially in key virulence factors, reveal that multiple mechanisms, such as point mutations, gain or loss of genes, as well as HGTs, contribute to the substantial phenotypic diversity of these versatile subspecies in various hosts.
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Affiliation(s)
- Jihye Park
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, USA
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Barchinger SE, Zhang X, Hester SE, Rodriguez ME, Harvill ET, Ades SE. sigE facilitates the adaptation of Bordetella bronchiseptica to stress conditions and lethal infection in immunocompromised mice. BMC Microbiol 2012; 12:179. [PMID: 22897969 PMCID: PMC3490749 DOI: 10.1186/1471-2180-12-179] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 06/25/2012] [Indexed: 11/28/2022] Open
Abstract
Background The cell envelope of a bacterial pathogen can be damaged by harsh conditions in the environment outside a host and by immune factors during infection. Cell envelope stress responses preserve the integrity of this essential compartment and are often required for virulence. Bordetella species are important respiratory pathogens that possess a large number of putative transcription factors. However, no cell envelope stress responses have been described in these species. Among the putative Bordetella transcription factors are a number of genes belonging to the extracytoplasmic function (ECF) group of alternative sigma factors, some of which are known to mediate cell envelope stress responses in other bacteria. Here we investigate the role of one such gene, sigE, in stress survival and pathogenesis of Bordetella bronchiseptica. Results We demonstrate that sigE encodes a functional sigma factor that mediates a cell envelope stress response. Mutants of B. bronchiseptica strain RB50 lacking sigE are more sensitive to high temperature, ethanol, and perturbation of the envelope by SDS-EDTA and certain β-lactam antibiotics. Using a series of immunocompromised mice deficient in different components of the innate and adaptive immune responses, we show that SigE plays an important role in evading the innate immune response during lethal infections of mice lacking B cells and T cells. SigE is not required, however, for colonization of the respiratory tract of immunocompetent mice. The sigE mutant is more efficiently phagocytosed and killed by peripheral blood polymorphonuclear leukocytes (PMNs) than RB50, and exhibits decreased cytotoxicity toward macrophages. These altered interactions with phagocytes could contribute to the defects observed during lethal infection. Conclusions Much of the work on transcriptional regulation during infection in B. bronchiseptica has focused on the BvgAS two-component system. This study reveals that the SigE regulon also mediates a discrete subset of functions associated with virulence. SigE is the first cell envelope stress-sensing system to be described in the bordetellae. In addition to its role during lethal infection of mice deficient in adaptive immunity, our results indicate that SigE is likely to be important for survival in the face of stresses encountered in the environment between hosts.
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Affiliation(s)
- Sarah E Barchinger
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, 16802, USA
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Ahuja U, Liu M, Tomida S, Park J, Souda P, Whitelegge J, Li H, Harvill ET, Parkhill J, Miller JF. Phenotypic and genomic analysis of hypervirulent human-associated Bordetella bronchiseptica. BMC Microbiol 2012; 12:167. [PMID: 22863321 PMCID: PMC3462115 DOI: 10.1186/1471-2180-12-167] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 07/17/2012] [Indexed: 01/17/2023] Open
Abstract
Background B. bronchiseptica infections are usually associated with wild or domesticated animals, but infrequently with humans. A recent phylogenetic analysis distinguished two distinct B. bronchiseptica subpopulations, designated complexes I and IV. Complex IV isolates appear to have a bias for infecting humans; however, little is known regarding their epidemiology, virulence properties, or comparative genomics. Results Here we report a characterization of the virulence of human-associated complex IV B. bronchiseptica strains. In in vitro cytotoxicity assays, complex IV strains showed increased cytotoxicity in comparison to a panel of complex I strains. Some complex IV isolates were remarkably cytotoxic, resulting in LDH release levels in A549 cells that were 10- to 20-fold greater than complex I strains. In vivo, a subset of complex IV strains was found to be hypervirulent, with an increased ability to cause lethal pulmonary infections in mice. Hypercytotoxicity in vitro and hypervirulence in vivo were both dependent on the activity of the bsc T3SS and the BteA effector. To clarify differences between lineages, representative complex IV isolates were sequenced and their genomes were compared to complex I isolates. Although our analysis showed there were no genomic sequences that can be considered unique to complex IV strains, there were several loci that were predominantly found in complex IV isolates. Conclusion Our observations reveal a T3SS-dependent hypervirulence phenotype in human-associated complex IV isolates, highlighting the need for further studies on the epidemiology and evolutionary dynamics of this B. bronchiseptica lineage.
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Affiliation(s)
- Umesh Ahuja
- Department of Microbiology, Immunology and Molecular Genetics, University of California, BSRB 254, 615 Charles E, Young Drive East, Los Angeles, CA 90095-1747, USA
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Phenotypic modulation of the virulent Bvg phase is not required for pathogenesis and transmission of Bordetella bronchiseptica in swine. Infect Immun 2011; 80:1025-36. [PMID: 22158743 DOI: 10.1128/iai.06016-11] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The majority of virulence gene expression in Bordetella is regulated by a two-component sensory transduction system encoded by the bvg locus. In response to environmental cues, the BvgAS regulatory system controls expression of a spectrum of phenotypic phases, transitioning between a virulent (Bvg(+)) phase and a nonvirulent (Bvg(-)) phase, a process referred to as phenotypic modulation. We hypothesized that the ability of Bordetella bronchiseptica to undergo phenotypic modulation is required at one or more points during the infectious cycle in swine. To investigate the Bvg phase-dependent contribution to pathogenesis of B. bronchiseptica in swine, we constructed a series of isogenic mutants in a virulent B. bronchiseptica swine isolate and compared each mutant to the wild-type isolate for its ability to colonize and cause disease. We additionally tested whether a BvgAS system capable of modulation is required for direct or indirect transmission. The Bvg(-) phase-locked mutant was never recovered from any respiratory tract site at any time point examined. An intermediate phase-locked mutant (Bvg(i)) was found in numbers lower than the wild type at all respiratory tract sites and time points examined and caused limited to no disease. In contrast, colonization of the respiratory tract and disease caused by the Bvg(+) phase-locked mutant and the wild-type strain were indistinguishable. The Bvg(+) phase-locked mutant transmitted to naïve pigs by both direct and indirect contact with efficiency equal to that of the wild-type isolate. These results indicate that while full activation of the BvgAS regulatory system is required for colonization and severe disease, it is not deleterious to direct and indirect transmission. Overall, our results demonstrate that the Bvg(+) phase is sufficient for respiratory infection and host-to-host transmission of B. bronchiseptica in swine.
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Transcriptional profiling of the iron starvation response in Bordetella pertussis provides new insights into siderophore utilization and virulence gene expression. J Bacteriol 2011; 193:4798-812. [PMID: 21742863 DOI: 10.1128/jb.05136-11] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Serological studies of patients with pertussis and the identification of antigenic Bordetella pertussis proteins support the hypothesis that B. pertussis perceives an iron starvation cue and expresses multiple iron source utilization systems in its natural human host environment. Furthermore, previous studies using a murine respiratory tract infection model showed that several of these B. pertussis iron systems are required for colonization and persistence and are differentially expressed over the course of infection. The present study examined genome-wide changes in B. pertussis gene transcript abundance in response to iron starvation in vitro. In addition to known iron source utilization genes, we identified a previously uncharacterized iron-repressed cytoplasmic membrane transporter system, fbpABC, that is required for the utilization of multiple structurally distinct siderophores including alcaligin, enterobactin, ferrichrome, and desferrioxamine B. Expression of type III secretion system genes was also found to be upregulated during iron starvation in both B. pertussis strain Tohama I and Bordetella bronchiseptica strain RB50. In a survey of type III secretion system protein production by an assortment of B. pertussis laboratory-adapted and low-passage clinical isolate strains, iron limitation increased the production and secretion of the type III secretion system-specific translocation apparatus tip protein Bsp22 in all Bvg-proficient strains. These results indicate that iron starvation in the infected host is an important environmental cue influencing not only Bordetella iron transport gene expression but also the expression of other important virulence-associated genes.
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Pertactin is required for Bordetella species to resist neutrophil-mediated clearance. Infect Immun 2010; 78:2901-9. [PMID: 20421378 DOI: 10.1128/iai.00188-10] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Pertactin (PRN) is an autotransporter protein produced by all members of the Bordetella bronchiseptica cluster, which includes B. pertussis, B. parapertussis, and B. bronchiseptica. It is a primary component of acellular pertussis vaccines, and anti-PRN antibody titers correlate with protection. In vitro studies have suggested that PRN functions as an adhesin and that an RGD motif located in the center of the passenger domain is important for this function. Two regions of PRN that contain sequence repeats (region 1 [R1] and R2) show polymorphisms among strains and have been implicated in vaccine-driven evolution. We investigated the role of PRN in pathogenesis using B. bronchiseptica and natural-host animal models. A Deltaprn mutant did not differ from wild-type B. bronchiseptica in its ability to adhere to epithelial and macrophage-like cells in vitro or to establish respiratory infection in rats but was cleared much faster than wild-type bacteria in a mouse lung inflammation model. Unlike wild-type B. bronchiseptica, the Deltaprn mutant was unable to cause a lethal infection in SCID-Bg mice, but, like wild-type bacteria, it was lethal for neutropenic mice. These results suggest that PRN plays a critical role in allowing Bordetella to resist neutrophil-mediated clearance. Mutants producing PRN proteins in which the RGD motif was replaced with RGE or in which R1 and R2 were deleted were indistinguishable from wild-type bacteria in all assays, suggesting that these sequences do not contribute to PRN function.
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Coscolla M, Gagneux S. Does M. tuberculosis genomic diversity explain disease diversity? ACTA ACUST UNITED AC 2010; 7:e43-e59. [PMID: 21076640 DOI: 10.1016/j.ddmec.2010.09.004] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The outcome of tuberculosis infection and disease is highly variable. This variation has been attributed primarily to host and environmental factors, but better understanding of the global genomic diversity in the M. tuberculosis complex (MTBC) suggests that bacterial factors could also be involved. Review of nearly 100 published reports shows that MTBC strains differ in their virulence and immunogenicity in experimental models, but whether this phenotypic variation plays a role in human disease remains unclear. Given the complex interactions between the host, the pathogen and the environment, linking MTBC genotypic diversity to experimental and clinical phenotypes requires an integrated systems epidemiology approach embedded in a robust evolutionary framework.
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Evidence for horizontal gene transfer of two antigenically distinct O antigens in Bordetella bronchiseptica. Infect Immun 2009; 77:3249-57. [PMID: 19528223 DOI: 10.1128/iai.01448-08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Host immunity is a major driving force of antigenic diversity, resulting in pathogens that can evade immunity induced by closely related strains. Here we show that two Bordetella bronchiseptica strains, RB50 and 1289, express two antigenically distinct O-antigen serotypes (O1 and O2, respectively). When 18 additional B. bronchiseptica strains were serotyped, all were found to express either the O1 or O2 serotype. Comparative genomic hybridization and PCR screening showed that the expression of either the O1 or O2 serotype correlated with the strain containing either the classical or alternative O-antigen locus, respectively. Multilocus sequence typing analysis of 49 B. bronchiseptica strains was used to build a phylogenetic tree, which revealed that the two O-antigen loci did not associate with a particular lineage, evidence that these loci are horizontally transferred between B. bronchiseptica strains. From experiments using mice vaccinated with purified lipopolysaccharide from strain RB50 (O1), 1289 (O2), or RB50Deltawbm (O antigen deficient), our data indicate that these O antigens do not confer cross-protection in vivo. The lack of cross-immunity between O-antigen serotypes appears to contribute to inefficient antibody-mediated clearance between strains. Together, these data are consistent with the idea that the O-antigen loci of B. bronchiseptica are horizontally transferred between strains and encode antigenically distinct serotypes, resulting in inefficient cross-immunity.
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