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Roop RM, Barton IS, Hopersberger D, Martin DW. Uncovering the Hidden Credentials of Brucella Virulence. Microbiol Mol Biol Rev 2021; 85:e00021-19. [PMID: 33568459 PMCID: PMC8549849 DOI: 10.1128/mmbr.00021-19] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Bacteria in the genus Brucella are important human and veterinary pathogens. The abortion and infertility they cause in food animals produce economic hardships in areas where the disease has not been controlled, and human brucellosis is one of the world's most common zoonoses. Brucella strains have also been isolated from wildlife, but we know much less about the pathobiology and epidemiology of these infections than we do about brucellosis in domestic animals. The brucellae maintain predominantly an intracellular lifestyle in their mammalian hosts, and their ability to subvert the host immune response and survive and replicate in macrophages and placental trophoblasts underlies their success as pathogens. We are just beginning to understand how these bacteria evolved from a progenitor alphaproteobacterium with an environmental niche and diverged to become highly host-adapted and host-specific pathogens. Two important virulence determinants played critical roles in this evolution: (i) a type IV secretion system that secretes effector molecules into the host cell cytoplasm that direct the intracellular trafficking of the brucellae and modulate host immune responses and (ii) a lipopolysaccharide moiety which poorly stimulates host inflammatory responses. This review highlights what we presently know about how these and other virulence determinants contribute to Brucella pathogenesis. Gaining a better understanding of how the brucellae produce disease will provide us with information that can be used to design better strategies for preventing brucellosis in animals and for preventing and treating this disease in humans.
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Affiliation(s)
- R Martin Roop
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Ian S Barton
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Dariel Hopersberger
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Daniel W Martin
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
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2
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Comparative proteomic analysis of outer membrane vesicles from Brucella suis, Brucella ovis, Brucella canis and Brucella neotomae. Arch Microbiol 2021; 203:1611-1626. [PMID: 33432377 PMCID: PMC7799404 DOI: 10.1007/s00203-020-02170-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 10/22/2020] [Accepted: 12/27/2020] [Indexed: 01/18/2023]
Abstract
Gram-negative bacteria release nanovesicles, called outer membrane vesicles (OMVs), from their outer membrane. Proteomics has been used to determine their composition. OMVs contain proteins able to elicit an immune response, so they have been proposed as a model to develop acellular vaccines. In this study, OMVs of Brucella suis, B. ovis, B. canis, and B. neotomae were purified and analyzed by SDS-PAGE, transmission electron microscopy and liquid chromatography coupled to mass spectrometry to determine the pan-proteome of these vesicles. In addition, antigenic proteins were detected by western blot with anti-Brucella sera. The in silico analysis of the pan-proteome revealed many homologous proteins, such as Omp16, Omp25, Omp31, SodC, Omp2a, and BhuA. Proteins contained in the vesicles from different Brucella species were detected by anti-Brucella sera. The occurrence of previously described immunogenic proteins derived from OMVs supports the use of these vesicles as candidates to be evaluated as an acellular brucellosis vaccine.
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Verdiguel-Fernández L, Oropeza-Navarro R, Ortiz A, Robles-Pesina MG, Ramírez-Lezama J, Castañeda-Ramírez A, Verdugo-Rodríguez A. Brucella melitensis omp31 Mutant Is Attenuated and Confers Protection Against Virulent Brucella melitensis Challenge in BALB/c Mice. J Microbiol Biotechnol 2020; 30:497-504. [PMID: 31986561 PMCID: PMC9728373 DOI: 10.4014/jmb.1908.08056] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
For control of brucellosis in small ruminants, attenuated B. melitensis Rev1 is used but it can be virulent for animals and human. Based on these aspects, it is essential to identify potential immunogens to avoid these problems in prevention of brucellosis. The majority of OMPs in the Omp25/31 family have been studied because these proteins are relevant in maintaining the integrity of the outer membrane but their implication in the virulence of the different species of this genus is not clearly described. Therefore, in this work we studied the role of Omp31 on virulence by determining the residual virulence and detecting lesions in spleen and testis of mice inoculated with the B. melitensis LVM31 mutant strain. In addition, we evaluated the conferred protection in mice immunized with the mutant strain against the challenge with the B. melitensis Bm133 virulent strain. Our results showed that the mutation of omp31 caused a decrease in splenic colonization without generating apparent lesions or histopathological changes apparent in both organs in comparison with the control strains and that the mutant strain conferred similar protection as the B. melitensis Rev1 vaccine strain against the challenge with B. melitensis Bm133 virulent strain. These results allow us to conclude that Omp31 plays an important role on the virulence of B. melitensis in the murine model, and due to the attenuation shown by the strain, it could be considered a vaccine candidate for the prevention of goat brucellosis.
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Affiliation(s)
- L Verdiguel-Fernández
- Laboratorio de Microbiología Molecular, Departamento de Microbiología e Inmunología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Avenida Universidad 3000, colonia UNAM CU, Coyoacán C.P 04510, CdMx, México
| | - R Oropeza-Navarro
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Adolfo Ortiz
- Unidad de Bioseguridad de Brucella, Departamento de Microbiología e Inmunología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Coyoacán, México
| | - MG Robles-Pesina
- Centro Nacional de Servicios de Diagnóstico en Salud Animal (CENASA), Servicio Nacional de Sanidad, Inocuidad y Calidad Agroalimentaria, Tecámac, México
| | - J Ramírez-Lezama
- Departamento de Patología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Coyoacán, CdMx, México
| | - A Castañeda-Ramírez
- Departamento de Zootecnia, Universidad Autónoma de Chapingo, Texcoco, México
| | - A Verdugo-Rodríguez
- Laboratorio de Microbiología Molecular, Departamento de Microbiología e Inmunología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Avenida Universidad 3000, colonia UNAM CU, Coyoacán C.P 04510, CdMx, México,Corresponding author Phone: +52-1-555622-58-97 E-mail:
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Hisham Y, Ashhab Y. Identification of Cross-Protective Potential Antigens against Pathogenic Brucella spp. through Combining Pan-Genome Analysis with Reverse Vaccinology. J Immunol Res 2018; 2018:1474517. [PMID: 30622973 PMCID: PMC6304850 DOI: 10.1155/2018/1474517] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Accepted: 11/04/2018] [Indexed: 01/18/2023] Open
Abstract
Brucellosis is a zoonotic infectious disease caused by bacteria of the genus Brucella. Brucella melitensis, Brucella abortus, and Brucella suis are the most pathogenic species of this genus causing the majority of human and domestic animal brucellosis. There is a need to develop a safe and potent subunit vaccine to overcome the serious drawbacks of the live attenuated Brucella vaccines. The aim of this work was to discover antigen candidates conserved among the three pathogenic species. In this study, we employed a reverse vaccinology strategy to compute the core proteome of 90 completed genomes: 55 B. melitensis, 17 B. abortus, and 18 B. suis. The core proteome was analyzed by a metasubcellular localization prediction pipeline to identify surface-associated proteins. The identified proteins were thoroughly analyzed using various in silico tools to obtain the most potential protective antigens. The number of core proteins obtained from analyzing the 90 proteomes was 1939 proteins. The surface-associated proteins were 177. The number of potential antigens was 87; those with adhesion score ≥ 0.5 were considered antigen with "high potential," while those with a score of 0.4-0.5 were considered antigens with "intermediate potential." According to a cumulative score derived from protein antigenicity, density of MHC-I and MHC-II epitopes, MHC allele coverage, and B-cell epitope density scores, a final list of 34 potential antigens was obtained. Remarkably, most of the 34 proteins are associated with bacterial adhesion, invasion, evasion, and adaptation to the hostile intracellular environment of macrophages which is adjusted to deprive Brucella of required nutrients. Our results provide a manageable list of potential protective antigens for developing a potent vaccine against brucellosis. Moreover, our elaborated analysis can provide further insights into novel Brucella virulence factors. Our next step is to test some of these antigens using an appropriate antigen delivery system.
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Affiliation(s)
- Yasmin Hisham
- Palestine-Korea Biotechnology Center, Palestine Polytechnic University, Hebron, State of Palestine
| | - Yaqoub Ashhab
- Palestine-Korea Biotechnology Center, Palestine Polytechnic University, Hebron, State of Palestine
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5
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Rahdar HA, Golmohammadi R, Mirnejad R, Ataee RA, Alishiri GH, Kazemian H. Diversity of virulence genes in Brucella melitensis and Brucella abortus detected from patients with rheumatoid arthritis. Microb Pathog 2018; 118:247-250. [PMID: 29578063 DOI: 10.1016/j.micpath.2018.03.034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/13/2018] [Accepted: 03/21/2018] [Indexed: 01/18/2023]
Abstract
The presence of Brucella melitensis and Brucella abortus genomes were investigated in the synovial fluid (SF) samples from 90 patients with rheumatoid arthritis (RA). DNA extraction and PCR assay were performed for simultaneous identification and discrimination of B. melitensis and B. abortus from the SF using three specific primers. After gel electrophoresis, the PCR products were confirmed by DNA sequencing. The cbg, omp31, manA, virB, and znuA virulence genes typing were performed by multiplex-PCR. Of the 90 samples, 14 were positive for B. melitensis (n = 9; 10%) and B. abortus (n = 5; 5.5%). The virulotyping of positive samples revealed the presence of all five virulence genes in B. melitensis. The virB, cbg, and om31 were detected in all five samples of B. abortus. In addition, zhuA and manA were detected in three (60%) and four (80%) samples, respectively, of the B. abortus-positive samples. Moreover, a total of 94.2% and 89.2% of the 14 positive samples were also found positive for manA and znuA, respectively. Our findings revealed that the Brucella spp. genomes can be detected in the SF of RA patients by the PCR-based method. We thus suggest that physicians should consider the Brucella spp. as indicators of potential RA for the timely diagnosis and treatment of RA.
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Affiliation(s)
- Hossein Ali Rahdar
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran; Department of Medical Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Golmohammadi
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.
| | - Reza Mirnejad
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Ramezan Ali Ataee
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran; Department of Medical Microbiology, Faculty of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Gholam Hossein Alishiri
- Department of Rheumatology, Faculty of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran; Exercise Physiology Research Center, Life Style Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Hossein Kazemian
- Department of Medical Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
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Naseri Z, Alikhani MY, Hashemi SH, Kamarehei F, Arabestani MR. Prevalence of the Most Common Virulence-Associated Genes among Brucella Melitensis Isolates from Human Blood Cultures in Hamadan Province, West of Iran. IRANIAN JOURNAL OF MEDICAL SCIENCES 2016; 41:422-9. [PMID: 27582592 PMCID: PMC4967487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Brucellosis is a widespread zoonotic disease causing considerable economic and public health problems. Despite animal vaccination, brucellosis remains endemic in some areas such as Iran, especially in the western Iranian province of Hamadan. We sought to detect some of the most common virulence-associated genes in Brucella isolated from human blood cultures to determine the prevalence of some virulence genes among Brucella isolates. Fifty-seven isolates were studied from patients with a clinical diagnosis of brucellosis who referred to the Infectious Diseases Ward of Sina Hospital in Hamadan Province, Iran, between April 2013 and July 2014. Blood samples were collected for the diagnosis of brucellosis using the BACTEC blood culture system. All of these isolates were confirmed by the bcsp31 Brucella-specific gene. We detected 11 virulence-associated genes of Brucella, namely cβg, virB, znuA, ure, bvfA, omp25, omp31, wbkA, mviN, manA, and manB, which are important for the pathogenesis of this bacterium in the intracellular environment by multiplex PCR. Totally, 149 patients with a clinical diagnosis of brucellosis were enrolled in this study. Fifty-seven (38.3%) patients had positive blood cultures. On biochemical and molecular testing, all of the isolates were Brucella melitensis. Ten of the virulence genes were detected among all of the 57 isolates, but the bvf gene was detected in 53 (93%) isolates. The high prevalence of virulence-associated genes among the Brucella isolates detected in Hamadan Province, Iran, underscores the pathogenicity of this bacterium in this region.
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Affiliation(s)
- Zahra Naseri
- Brucellosis Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mohammad Yousef Alikhani
- Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Seyed Hamid Hashemi
- Brucellosis Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Farideh Kamarehei
- Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mohammad Reza Arabestani
- Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
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Cui M, Wang T, Xu J, Ke Y, Du X, Yuan X, Wang Z, Gong C, Zhuang Y, Lei S, Su X, Wang X, Huang L, Zhong Z, Peng G, Yuan J, Chen Z, Wang Y. Impact of Hfq on global gene expression and intracellular survival in Brucella melitensis. PLoS One 2013; 8:e71933. [PMID: 23977181 PMCID: PMC3747064 DOI: 10.1371/journal.pone.0071933] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 07/04/2013] [Indexed: 01/30/2023] Open
Abstract
Brucella melitensis is a facultative intracellular bacterium that replicates within macrophages. The ability of brucellae to survive and multiply in the hostile environment of host macrophages is essential to its virulence. The RNA-binding protein Hfq is a global regulator that is involved in stress resistance and pathogenicity. Here we demonstrate that Hfq is essential for stress adaptation and intracellular survival in B. melitensis. A B. melitensis hfq deletion mutant exhibits reduced survival under environmental stresses and is attenuated in cultured macrophages and mice. Microarray-based transcriptome analyses revealed that 359 genes involved in numerous cellular processes were dysregulated in the hfq mutant. From these same samples the proteins were also prepared for proteomic analysis to directly identify Hfq-regulated proteins. Fifty-five proteins with significantly affected expression were identified in the hfq mutant. Our results demonstrate that Hfq regulates many genes and/or proteins involved in metabolism, virulence, and stress responses, including those potentially involved in the adaptation of Brucella to the oxidative, acid, heat stress, and antibacterial peptides encountered within the host. The dysregulation of such genes and/or proteins could contribute to the attenuated hfq mutant phenotype. These findings highlight the involvement of Hfq as a key regulator of Brucella gene expression and facilitate our understanding of the role of Hfq in environmental stress adaptation and intracellular survival of B. melitensis.
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Affiliation(s)
- Mingquan Cui
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
- College of Veterinary Medicine, Sichuan Agricultural University, Ya’an, China
| | - Tongkun Wang
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jie Xu
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
| | - Yuehua Ke
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
| | - Xinying Du
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
| | - Xitong Yuan
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
| | - Zhoujia Wang
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
| | - Chunli Gong
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
| | - Yubin Zhuang
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
- College of Veterinary Medicine, Sichuan Agricultural University, Ya’an, China
| | - Shuangshuang Lei
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
- College of Veterinary Medicine, Sichuan Agricultural University, Ya’an, China
| | - Xiao Su
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
| | - Xuesong Wang
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
| | - Liuyu Huang
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
| | - Zhijun Zhong
- College of Veterinary Medicine, Sichuan Agricultural University, Ya’an, China
| | - Guangneng Peng
- College of Veterinary Medicine, Sichuan Agricultural University, Ya’an, China
| | - Jing Yuan
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
| | - Zeliang Chen
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
| | - Yufei Wang
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing, China
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Ben-Tekaya H, Gorvel JP, Dehio C. Bartonella and Brucella--weapons and strategies for stealth attack. Cold Spring Harb Perspect Med 2013; 3:3/8/a010231. [PMID: 23906880 DOI: 10.1101/cshperspect.a010231] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Bartonella spp. and Brucella spp. are closely related α-proteobacterial pathogens that by distinct stealth-attack strategies cause chronic infections in mammals including humans. Human infections manifest by a broad spectrum of clinical symptoms, ranging from mild to fatal disease. Both pathogens establish intracellular replication niches and subvert diverse pathways of the host's immune system. Several virulence factors allow them to adhere to, invade, proliferate, and persist within various host-cell types. In particular, type IV secretion systems (T4SS) represent essential virulence factors that transfer effector proteins tailored to recruit host components and modulate cellular processes to the benefit of the bacterial intruders. This article puts the remarkable features of these two pathogens into perspective, highlighting the mechanisms they use to hijack signaling and trafficking pathways of the host as the basis for their stealthy infection strategies.
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Affiliation(s)
- Houchaima Ben-Tekaya
- Focal Area Infection Biology, Biozentrum, University of Basel, 4052 Basel, Switzerland
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Hemin binding protein C is found in outer membrane vesicles and protects Bartonella henselae against toxic concentrations of hemin. Infect Immun 2012; 80:929-42. [PMID: 22232189 DOI: 10.1128/iai.05769-11] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Bartonella species are gram-negative, emerging bacterial pathogens found in two distinct environments. In the gut of the obligately hematophagous arthropod vector, bartonellae are exposed to concentrations of heme that are toxic to other bacteria. In the bloodstream of the mammalian host, access to heme and iron is severely restricted. Bartonellae have unusually high requirements for heme, which is their only utilizable source of iron. Although heme is essential for Bartonella survival, little is known about genes involved in heme acquisition and detoxification. We developed a strategy for high-efficiency transposon mutagenesis to screen for genes in B. henselae heme binding and uptake pathways. We identified a B. henselae transposon mutant that constitutively expresses the hemin binding protein C (hbpC) gene. In the wild-type strain, transcription of B. henselae hbpC was upregulated at arthropod temperature (28°C), compared to mammalian temperature (37°C). In the mutant strain, temperature-dependent regulation was absent. We demonstrated that HbpC binds hemin and localizes to the B. henselae outer membrane and outer membrane vesicles. Overexpression of hbpC in B. henselae increased resistance to heme toxicity, implicating HbpC in protection of B. henselae from the toxic levels of heme present in the gut of the arthropod vector. Experimental inoculation of cats with B. henselae strains demonstrated that both constitutive expression and deletion of hbpC affect the ability of B. henselae to infect the cat host. Modulation of hbpC expression appears to be a strategy employed by B. henselae to survive in the arthropod vector and the mammalian host.
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Abstract
There is currently no licensed vaccine for brucellosis in humans. Available animal vaccines may cause disease and are considered unsuitable for use in humans. However, the causative pathogen, Brucella, is among the most common causes of laboratory-acquired infections and is a Center for Disease Control category B select agent. Thus, human vaccines for brucellosis are required. This review highlights the considerations that are needed in the journey to develop a human vaccine, including animal models, and includes an assessment of the current status of novel vaccine candidates.
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Affiliation(s)
- Stuart D Perkins
- Department of Biomedical Sciences, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire, UK
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11
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Rossetti CA, Galindo CL, Lawhon SD, Garner HR, Adams LG. Brucella melitensis global gene expression study provides novel information on growth phase-specific gene regulation with potential insights for understanding Brucella:host initial interactions. BMC Microbiol 2009; 9:81. [PMID: 19419566 PMCID: PMC2684542 DOI: 10.1186/1471-2180-9-81] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Accepted: 05/06/2009] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Brucella spp. are the etiological agents of brucellosis, a zoonotic infectious disease that causes abortion in animals and chronic debilitating illness in humans. Natural Brucella infections occur primarily through an incompletely defined mechanism of adhesion to and penetration of mucosal epithelium. In this study, we characterized changes in genome-wide transcript abundance of the most and the least invasive growth phases of B. melitensis cultures to HeLa cells, as a preliminary approach for identifying candidate pathogen genes involved in invasion of epithelial cells. RESULTS B. melitensis at the late logarithmic phase of growth are more invasive to HeLa cells than mid-logarithmic or stationary growth phases. Microarray analysis of B. melitensis gene expression identified 414 up- and 40 down-regulated genes in late-log growth phase (the most invasive culture) compared to the stationary growth phase (the least invasive culture). As expected, the majority of up-regulated genes in late-log phase cultures were those associated with growth, including DNA replication, transcription, translation, intermediate metabolism, energy production and conversion, membrane transport, and biogenesis of the cell envelope and outer membrane; while the down-regulated genes were distributed among several functional categories. CONCLUSION This Brucella global expression profile study provides novel information on growth phase-specific gene expression. Further characterization of some genes found differentially expressed in the most invasive culture will likely bring new insights into the initial molecular interactions between Brucella and its host.
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Affiliation(s)
- Carlos A Rossetti
- Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77483-4467, USA.
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12
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Brucella: A pathogen without classic virulence genes. Vet Microbiol 2008; 129:1-14. [DOI: 10.1016/j.vetmic.2007.11.023] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2006] [Revised: 11/19/2007] [Accepted: 11/22/2007] [Indexed: 01/18/2023]
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13
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Manterola L, Guzmán-Verri C, Chaves-Olarte E, Barquero-Calvo E, de Miguel MJ, Moriyón I, Grilló MJ, López-Goñi I, Moreno E. BvrR/BvrS-controlled outer membrane proteins Omp3a and Omp3b are not essential for Brucella abortus virulence. Infect Immun 2007; 75:4867-74. [PMID: 17664262 PMCID: PMC2044513 DOI: 10.1128/iai.00439-07] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The Brucella abortus two-component regulatory system BvrR/BvrS controls the expression of outer membrane proteins (Omp) Omp3a (Omp25) and Omp3b (Omp22). Disruption of bvrS or bvrR generates avirulent mutants with altered cell permeability, higher sensitivity to microbicidal peptides, and complement. Consequently, the role of Omp3a and Omp3b in virulence was examined. Similar to bvrS or bvrR mutants, omp3a and omp3b mutants displayed increased attachment to cells, indicating surface alterations. However, they showed unaltered permeability; normal expression of Omp10, Omp16, Omp19, Omp2b, and Omp1; native hapten polysaccharide; and lipopolysaccharide and were resistant to complement and polymyxin B at ranges similar to those of the wild-type (WT) counterpart. Likewise, omp3a and omp3b mutants were able to replicate in murine macrophages and in HeLa cells, were resistant to the killing action of human neutrophils, and persisted in mice, like the WT strain. Murine macrophages infected with the omp3a mutant generated slightly higher levels of tumor necrosis factor alpha than the WT, whereas the bvrS mutant induced lower levels of this cytokine. Since the absence of Omp3a or Omp3b does not result in attenuation, it can be concluded that BvrR/BvrS influences additional Brucella properties involved in virulence. Our results are discussed in the light of previous works suggesting that disruption of omp3a generates attenuated Brucella strains, and we speculate on the role of group 3 Omps.
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Affiliation(s)
- Lorea Manterola
- Departamento de Microbiología y Parasitología, Universidad de Navarra, 31008 Pamplona, Spain
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14
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Battisti JM, Smitherman LS, Sappington KN, Parrow NL, Raghavan R, Minnick MF. Transcriptional regulation of the heme binding protein gene family of Bartonella quintana is accomplished by a novel promoter element and iron response regulator. Infect Immun 2007; 75:4373-85. [PMID: 17576755 PMCID: PMC1951173 DOI: 10.1128/iai.00497-07] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
We previously identified a five-member family of hemin-binding proteins (Hbp's) of Bartonella quintana that bind hemin on the outer surface but share no homology with known bacterial heme receptors. Subsequently, we demonstrated that expression of the hbp family is significantly influenced by oxygen, heme, and temperature conditions encountered by the pathogen in the human host and the body louse vector; e.g., we observed a dramatic (>100-fold) increase in hbpC transcript levels in response to the "louse-like" temperature of 30 degrees C. The goal of the present study was to identify a transcription factor(s) involved in the coordinated and differential regulation of the hbp family. First, we used quantitative real-time PCR (qRT-PCR) to show that the same environmental conditions generate parallels in the transcript profiles of four candidate transcriptional regulators (Irr, Fur, RirA, and BatR) described in the order Rhizobiales, with the greatest overall change in the transcription of irr (a >5-fold decrease) at a "louse-like" temperature, suggesting that Irr may function as an hbpC repressor. Second, a B. quintana strain hyperexpressing Irr was constructed; it exhibits a "bloodstream-like" hbp transcript profile in the absence of an environmental stimulus (i.e., hbpC is repressed and hbpA, hbpD, and hbpE mRNAs are relatively abundant). Furthermore, when this strain is grown at a "louse-like" temperature, an inversion of the transcript profile occurs, where derepression of hbpC and repression of hbpA, hbpD, and hbpE are readily evident, strongly suggesting that Irr and temperature influence hbp family expression. Third, electrophoretic mobility shift analyses show that recombinant Irr binds specifically to the hbpC promoter region at a sequence that is highly conserved in Bartonella hbp genes, which we designated the hbp family box, or "H-box." Fourth, we used the H-box to search the B. quintana genome and discovered a number of intriguing open reading frames, e.g., five members of a six-member family of cohemolysin autotransporters. Finally, qRT-PCR data regarding the effects of Fur and RirA overexpression on the hbp family are provided; they show that Fur's effect on the hbp family is relatively minor but RirA generates a "bloodstream-like" hbp transcript profile in the absence of an environmental stimulus, as observed for the Irr-hyperexpressing strain.
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Affiliation(s)
- James M Battisti
- Division of Biological Sciences, The University of Montana, Missoula, MT 59812, USA
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Caro-Hernández P, Fernández-Lago L, de Miguel MJ, Martín-Martín AI, Cloeckaert A, Grilló MJ, Vizcaíno N. Role of the Omp25/Omp31 family in outer membrane properties and virulence of Brucella ovis. Infect Immun 2007; 75:4050-61. [PMID: 17562767 PMCID: PMC1952020 DOI: 10.1128/iai.00486-07] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The genes coding for the five outer membrane proteins (OMPs) of the Omp25/Omp31 family expected to be located in the outer membrane (OM) of rough virulent Brucella ovis PA were inactivated to evaluate their role in virulence and OM properties. The OM properties of the mutant strains and of the mutants complemented with the corresponding wild-type genes were analyzed, in comparison with the parental strain and rough B. abortus RB51, in several tests: (i) binding of anti-Omp25 and anti-Omp31 monoclonal antibodies, (ii) autoagglutination of bacterial suspensions, and (iii) assessment of susceptibility to polymyxin B, sodium deoxycholate, hydrogen peroxide, and nonimmune ram serum. A tight balance of the members of the Omp25/Omp31 family was seen to be essential for the stability of the B. ovis OM, and important differences between the OMs of B. ovis PA and B. abortus RB51 rough strains were observed. Regarding virulence, the absence of Omp25d and Omp22 from the OM of B. ovis PA led to a drastic reduction in spleen colonization in mice. While the greater susceptibility of the Deltaomp22 mutant to nonimmune serum and its difficulty in surviving in the stationary phase might be on the basis of its dramatic attenuation, no defects in the OM able to explain the attenuation of the Deltaomp25d mutant were found, especially considering that the fully virulent Deltaomp25c mutant displayed more important OM defects. Accordingly, Omp25d, and perhaps Omp22, could be directly involved in the penetration and/or survival of B. ovis inside host cells. This aspect, together with the role of Omp25d and Omp22 in the virulence both of B. ovis in rams and of other Brucella species, should be thoroughly evaluated in future studies.
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Affiliation(s)
- Paola Caro-Hernández
- Departamento de Microbiología y Genética, Edificio Departamental, Universidad de Salamanca, Plaza Doctores de la Reina s/n, 37007 Salamanca, Spain
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Battisti JM, Sappington KN, Smitherman LS, Parrow NL, Minnick MF. Environmental signals generate a differential and coordinated expression of the heme receptor gene family of Bartonella quintana. Infect Immun 2006; 74:3251-61. [PMID: 16714552 PMCID: PMC1479232 DOI: 10.1128/iai.00245-06] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 03/10/2006] [Accepted: 03/17/2006] [Indexed: 01/18/2023] Open
Abstract
Of all bacteria, Bartonella quintana has the highest reported in vitro hemin requirement, yet an explanation for this remains elusive. To produce diseases such as trench fever, endocarditis, and bacillary angiomatosis, B. quintana must survive and replicate in the disparate environments of the Pediculus humanus corporis (body louse) gut and the human vasculature. We previously identified a five-member family of hemin binding proteins (Hbps) synthesized by B. quintana that bind hemin on the outer surface but share no similarity to known bacterial heme receptors. In the present study, we examine the transcription, regulation, and synthesis of this virulence factor family by cultivation of the bacterium in environments that simulate natural heme, oxygen, and temperature conditions encountered in the host and insect vector. First, quantitative real-time PCR data show that hbpC expression is regulated by temperature, where a >100-fold increase in transcript quantity was seen at 30 degrees C relative to 37 degrees C, suggesting that HbpC synthesis would be greatest in the cooler temperature of the louse. Second, cultivation at human bloodstream oxygen concentration (5% relative to 21% atmospheric) significantly decreases the transcript quantity of all hbp genes, indicating that expression is influenced by O2 and/or reactive oxygen species. Third, a differential expression pattern within the hbp family is revealed when B. quintana is grown in a range of hemin concentrations: subgroup I (hbpC and hbpB) predominates in a simulated louse environment (high heme), and subgroup II (hbpA, hbpD, and hbpE) is preferentially expressed in a simulated human background (low heme). By using two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblotting, and matrix-assisted laser desorption ionization-time of flight mass spectrometry fingerprinting, we demonstrate that synthesis of HbpA correlates with hbpA transcript increases observed at low hemin concentrations. Finally, an hbpA promoter-lacZ reporter construct in B. quintana demonstrates that a transcriptional regulator(s) is controlling the expression of hbpA through a cis-acting regulatory element located in the hbpA promoter region.
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Affiliation(s)
- James M Battisti
- Division of Biological Sciences, The University of Montana, Missoula, MT 59812, USA
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