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Chen X, Zhao Y, Su L, Wang L, Ma X, Zhang B, Su Y. Enhanced immune effects and protection conferred by simultaneously targeting GAPDH, SeM, and EAG of S. equi via TLR4. Res Vet Sci 2021; 138:100-108. [PMID: 34126448 DOI: 10.1016/j.rvsc.2021.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 04/26/2021] [Accepted: 06/01/2021] [Indexed: 10/21/2022]
Abstract
Strangles, which is caused by Streptococcus equi subspecies equi, is one of the most prevalent equine infectious diseases and poses heavy economic losses worldwide. Although various vaccines have been used for decades, they seemed to be sub-optimal to demonstrate effective protection, and the antigen component of vaccines against S. equi remains to be optimized. In the present study, three target antigens (M-like protein, α2-macroglobulin and IgG-binding protein, and glyceraldehyde-3-phosphate dehydrogenase) were selected and expressed. Mice were immunized and challenged, and their immune response and efficacy were evaluated. The results revealed that this optimized multi-antigen treatment elicited a high expression level of T-cell receptor, major histocompatibility complex I, toll-like receptor TLR-4, and increased specific antibody. In addition, the challenge experiment showed an evidently improved protection efficacy. The present work demonstrated that these three proteins might be used as a promising multicomponent subunit vaccine candidate against S. equi infection.
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Affiliation(s)
- Xiaomeng Chen
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Yanan Zhao
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Lingling Su
- Xinjiang Academy of Animal Science,Urumqi, Xinjiang, China
| | - Li Wang
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Xiaohui Ma
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Baojiang Zhang
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Yan Su
- Department of Microbiology and Immunology, College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang, China.
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Bustos CP, Muñoz AJ, Guida N, Waller A, Mesplet M. Novel seM-types of Streptococcus equi subsp. equi identified in isolates circulating in Argentina. Equine Vet J 2021; 54:132-138. [PMID: 33420757 DOI: 10.1111/evj.13420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/09/2020] [Accepted: 01/03/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND Strangles is a worldwide infectious disease caused by Streptococcus equi subsp. equi that affects the upper respiratory tract of horses. Streptococcus equi subsp. equi characterisation by seM-typing is internationally used for epidemiological studies and comparison of isolates. OBJECTIVES To identify and to compare the seM-types of Argentinian isolates of Streptococcus equi subsp. equi. STUDY DESIGN Investigation of bacterial isolates using molecular and phylogenetic approaches. METHODS A total of 59 Argentinian isolates of Streptococcus equi subsp. equi obtained between 2007 and 2019 were studied by seM-typing. The sequence similarity of Argentinian seM-types and the other alleles available on the seM database was determined using BLAST and phylogenetic analysis was performed using the Neighbour-Joining algorithm. The amino acid sequences were predicted and compared with the predicted amino acid sequence of the reference strain 4047 using the MEGA 7 software and PROVEAN tool. RESULTS Eight seM-types were found among the isolates. Only one of them (seM-61) has been previously reported and the other seven alleles (seM-129, seM-130, seM-131, seM-132, seM-133, seM-134 and seM-135) were novel seM sequences. High genetic similarity was observed among the Argentinian seM-types, with the exception of seM-130. No functional effects of amino acid differences were predicted. MAIN LIMITATIONS The number of related and unrelated isolates per year. CONCLUSIONS Seven novel seM-types and seM-61 that were previously reported in Brazil were circulating in Argentina which were identified as circulating in Argentinian horses between 2007 and 2019. The high genetic similarity among the Argentinian and Brazilian seM-types suggests that there is a geographical distribution of strain types. The geographical restriction of strains is likely to reflect the movement of horses between different equine disciplines and neighbouring countries.
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Affiliation(s)
- Carla P Bustos
- Universidad de Buenos Aires, Facultad de Ciencias Veterinarias, Cátedra de Enfermedades Infecciosas, Ciudad Autónoma de Buenos Aires, Argentina
| | - Alejandra J Muñoz
- Universidad de Buenos Aires, Facultad de Ciencias Veterinarias, Cátedra de Enfermedades Infecciosas, Ciudad Autónoma de Buenos Aires, Argentina
| | - Nora Guida
- Universidad de Buenos Aires, Facultad de Ciencias Veterinarias, Cátedra de Enfermedades Infecciosas, Ciudad Autónoma de Buenos Aires, Argentina
| | | | - María Mesplet
- Universidad de Buenos Aires, Facultad de Ciencias Veterinarias, Cátedra de Enfermedades Infecciosas, Ciudad Autónoma de Buenos Aires, Argentina
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First Report of Molecular Characterization of Argentine Isolates of Streptococcus equi subsp. equi by Pulsed-Field Gel Electrophoresis. J Equine Vet Sci 2017. [DOI: 10.1016/j.jevs.2017.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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4
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Tracing outbreaks of Streptococcus equi infection (strangles) in horses using sequence variation in the seM gene and pulsed-field gel electrophoresis. Vet Microbiol 2011; 153:144-9. [PMID: 21511406 DOI: 10.1016/j.vetmic.2011.03.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 03/16/2011] [Accepted: 03/23/2011] [Indexed: 11/20/2022]
Abstract
Strangles is a serious respiratory disease in horses caused by Streptococcus equi subspecies equi (S. equi). Transmission of the disease occurs by direct contact with an infected horse or contaminated equipment. Genetically, S. equi strains are highly homogenous and differentiation of strains has proven difficult. However, the S. equi M-protein SeM contains a variable N-terminal region and has been proposed as a target gene to distinguish between different strains of S. equi and determine the source of an outbreak. In this study, strains of S. equi (n=60) from 32 strangles outbreaks in Sweden during 1998-2003 and 2008-2009 were genetically characterized by sequencing the SeM protein gene (seM), and by pulsed-field gel electrophoresis (PFGE). Swedish strains belonged to 10 different seM types, of which five have not previously been described. Most were identical or highly similar to allele types from strangles outbreaks in the UK. Outbreaks in 2008/2009 sharing the same seM type were associated by geographic location and/or type of usage of the horses (racing stables). Sequencing of the seM gene generally agreed with pulsed-field gel electrophoresis profiles. Our data suggest that seM sequencing as a epidemiological tool is supported by the agreement between seM and PFGE and that sequencing of the SeM protein gene is more sensitive than PFGE in discriminating strains of S. equi.
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Guss B, Flock M, Frykberg L, Waller AS, Robinson C, Smith KC, Flock JI. Getting to grips with strangles: an effective multi-component recombinant vaccine for the protection of horses from Streptococcus equi infection. PLoS Pathog 2009; 5:e1000584. [PMID: 19763180 PMCID: PMC2736577 DOI: 10.1371/journal.ppat.1000584] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Accepted: 08/24/2009] [Indexed: 11/18/2022] Open
Abstract
Streptococcus equi subspecies equi (S. equi) is a clonal, equine host-adapted pathogen of global importance that causes a suppurative lymphodendopathy of the head and neck, more commonly known as Strangles. The disease is highly prevalent, can be severe and is highly contagious. Antibiotic treatment is usually ineffective. Live attenuated vaccine strains of S. equi have shown adverse reactions and they suffer from a short duration of immunity. Thus, a safe and effective vaccine against S. equi is highly desirable. The bacterium shows only limited genetic diversity and an effective vaccine could confer broad protection to horses throughout the world. Welsh mountain ponies (n = 7) vaccinated with a combination of seven recombinant S. equi proteins were significantly protected from experimental infection by S. equi, resembling the spontaneous disease. Vaccinated horses had significantly reduced incidence of lymph node swelling (p = 0.0013) lymph node abscessation (p = 0.00001), fewer days of pyrexia (p = 0.0001), reduced pathology scoring (p = 0.005) and lower bacterial recovery from lymph nodes (p = 0.004) when compared with non-vaccinated horses (n = 7). Six of 7 vaccinated horses were protected whereas all 7 non-vaccinated became infected. The protective antigens consisted of five surface localized proteins and two IgG endopeptidases. A second vaccination trial (n = 7+7), in which the IgG endopeptidases were omitted, demonstrated only partial protection against S. equi, highlighting an important role for these vaccine components in establishing a protective immune response. S. equi shares >80% sequence identity with Streptococcus pyogenes. Several of the components utilized here have counterparts in S. pyogenes, suggesting that our findings have broader implications for the prevention of infection with this important human pathogen. This is one of only a few demonstrations of protection from streptococcal infection conferred by a recombinant multi-component subunit vaccine in a natural host. Numerous research groups have vaccinated, using recombinant antigens, against streptococcal infections in mouse model systems and shown protection. We have here demonstrated efficient protective vaccination of the natural host, the horse, using recombinant antigens. Streptococcus equi subspecies equi (S. equi) is an equine host-adapted and highly contagious pathogen of global importance. Six out of seven Welsh mountain ponies vaccinated with a combination of seven recombinant S. equi proteins were protected from experimental infection as assessed by clinical examination, pyrexia, lymph node swelling, inflammation, bacterial recovery, and post mortem examination. The protective antigens consisted of five surface localized proteins and two endopeptidases that are specific for IgG; the latter were shown to be of major importance for efficacy. Several of the antigens used here have similarities in Streptococcus pyogenes, implying that our findings are of importance for development of a vaccine against this important human pathogen.
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Affiliation(s)
- Bengt Guss
- Department of Microbiology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Margareta Flock
- Department of Microbiology, Tumor and Cellbiology, Karolinska Institutet, Stockholm, Sweden
| | - Lars Frykberg
- Department of Microbiology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Andrew S. Waller
- Department of Bacteriology, Animal Health Trust, Lanwades Park, Kentford, Newmarket, United Kingdom
| | - Carl Robinson
- Department of Bacteriology, Animal Health Trust, Lanwades Park, Kentford, Newmarket, United Kingdom
| | - Ken C. Smith
- Department of Pathology and Infectious Diseases, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Herts, United Kingdom
| | - Jan-Ingmar Flock
- Department of Microbiology, Tumor and Cellbiology, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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Heather Z, Holden MTG, Steward KF, Parkhill J, Song L, Challis GL, Robinson C, Davis-Poynter N, Waller AS. A novel streptococcal integrative conjugative element involved in iron acquisition. Mol Microbiol 2009; 70:1274-92. [PMID: 18990191 PMCID: PMC3672683 DOI: 10.1111/j.1365-2958.2008.06481.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In this study, we determined the function of a novel non-ribosomal peptide synthetase (NRPS) system carried by a streptococcal integrative conjugative element (ICE), ICESe2. The NRPS shares similarity with the yersiniabactin system found in the high-pathogenicity island of Yersinia sp. and is the first of its kind to be identified in streptococci. We named the NRPS product 'equibactin' and genes of this locus eqbA-N. ICESe2, although absolutely conserved in Streptococcus equi, the causative agent of equine strangles, was absent from all strains of the closely related opportunistic pathogen Streptococcus zooepidemicus. Binding of EqbA, a DtxR-like regulator, to the eqbB promoter was increased in the presence of cations. Deletion of eqbA resulted in a small-colony phenotype. Further deletion of the irp2 homologue eqbE, or the genes eqbH, eqbI and eqbJ encoding a putative ABC transporter, or addition of the iron chelator nitrilotriacetate, reversed this phenotype, implicating iron toxicity. Quantification of (55)Fe accumulation and sensitivity to streptonigrin suggested that equibactin is secreted by S. equi and that the eqbH, eqbI and eqbJ genes are required for its associated iron import. In agreement with a structure-based model of equibactin synthesis, supplementation of chemically defined media with salicylate was required for equibactin production.
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Affiliation(s)
- Zoe Heather
- Centre for Preventive Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, UK
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Webb K, Jolley KA, Mitchell Z, Robinson C, Newton JR, Maiden MCJ, Waller A. Development of an unambiguous and discriminatory multilocus sequence typing scheme for the Streptococcus zooepidemicus group. MICROBIOLOGY-SGM 2008; 154:3016-3024. [PMID: 18832307 DOI: 10.1099/mic.0.2008/018911-0] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The zoonotic pathogen Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) is commonly found harmlessly colonizing the equine nasopharynx. Occasionally, strains can invade host tissues or cross species barriers, and S. zooepidemicus is associated with numerous different diseases in a variety of hosts, including inflammatory airway disease and abortion in horses, pneumonia in dogs and meningitis in humans. A biovar of S. zooepidemicus, Streptococcus equi subsp. equi, is the causative agent of strangles, one of the most important infections of horses worldwide. We report here the development of the first multilocus sequence typing (MLST) scheme for S. zooepidemicus and its exploitation to define the population genetic structure of these related pathogens. A total of 130 unique sequence types were identified from 277 isolates of diverse geographical and temporal origin. Isolates of S. equi shared a recent evolutionary ancestor with isolates of S. zooepidemicus that were significantly associated with cases of uterine infection or abortion in horses (P<0.001). Isolates of S. zooepidemicus from three UK outbreaks of acute fatal haemorrhagic pneumonia in dogs during 1999, 2001 and 2008 were found to be related to isolates from three outbreaks of this disease in the USA during 2005, 1993 and 2006, respectively. Our data provide strong evidence that S. equi evolved from an ancestral S. zooepidemicus strain and that certain related strains of S. zooepidemicus have a greater propensity to infect particular hosts and tissues.
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Affiliation(s)
- Katy Webb
- Centre for Preventive Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, UK
| | - Keith A Jolley
- The Peter Medawar Building for Pathogen Research and Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3SY, UK
| | - Zoe Mitchell
- Centre for Preventive Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, UK
| | - Carl Robinson
- Centre for Preventive Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, UK
| | - J Richard Newton
- Centre for Preventive Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, UK
| | - Martin C J Maiden
- The Peter Medawar Building for Pathogen Research and Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3SY, UK
| | - Andrew Waller
- Centre for Preventive Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, UK
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8
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Hong-Jie F, Fu-yu T, Ying M, Cheng-ping L. Virulence and antigenicity of the szp-gene deleted Streptococcus equi ssp. zooepidemicus mutant in mice. Vaccine 2008; 27:56-61. [PMID: 18983882 DOI: 10.1016/j.vaccine.2008.10.037] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2008] [Revised: 10/03/2008] [Accepted: 10/12/2008] [Indexed: 11/16/2022]
Abstract
Streptococcus equi ssp. zooepidemicus (SEZ) causes serious disease in pigs. M-like protein (SzP) of SEZ is a virulence factor with opsonin function. To fabricate better vaccine against SEZ, We have generated a szp-knockout strain by homologous recombination. Two fragments, upstream and downstream of the szp gene, were obtained by genome walking. The vector was then used to delete a 1090 bp segment of szp gene from a strain of SEZ (ATCC35246). The mutant strain had 1000-fold decrease in LD50 as compared with wild type, and provided 85% protection against challenge with a virulent strain when administered as a live vaccine. Semi-quantitative RT-PCR analysis showed a marked increased in levels of IL-4 and IFN-gamma mRNA in immunized mice. These data demonstrate that szp-knockout strain is a better candidate for vaccine development.
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Affiliation(s)
- Fan Hong-Jie
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
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9
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Lewis MJ, Meehan M, Owen P, Woof JM. A common theme in interaction of bacterial immunoglobulin-binding proteins with immunoglobulins illustrated in the equine system. J Biol Chem 2008; 283:17615-23. [PMID: 18411272 PMCID: PMC2427354 DOI: 10.1074/jbc.m709844200] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
The M protein of Streptococcus equi subsp. equi known as fibrinogen-binding protein (FgBP) is a cell wall-associated protein with antiphagocytic activity that binds IgG. Recombinant versions of the seven equine IgG subclasses were used to investigate the subclass specificity of FgBP. FgBP bound predominantly to equine IgG4 and IgG7, with little or no binding to the other subclasses. Competitive binding experiments revealed that FgBP could inhibit the binding of staphylococcal protein A and streptococcal protein G to both IgG4 and IgG7, implicating the Fc interdomain region in binding to FgBP. To identify which of the two IgG Fc domains contributed to the interaction with FgBP, we tested two human IgG1/IgA1 domain swap mutants and found that both domains are required for full binding, with the CH3 domain playing a critical role. The binding site for FgBP was further localized using recombinant equine IgG7 antibodies with single or double point mutations to residues lying at the CH2-CH3 interface. We found that interaction of FgBP with equine IgG4 and IgG7 was able to disrupt C1q binding and antibody-mediated activation of the classical complement pathway, demonstrating an effective means by which S. equi may evade the immune response. The mode of interaction of FgBP with IgG fits a common theme for bacterial Ig-binding proteins. Remarkably, for those interactions studied in detail, it emerges that all the Ig-binding proteins target the CH2-CH3 domain interface, regardless of specificity for IgG or IgA, streptococcal or staphylococcal origin, or host species (equine or human).
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Affiliation(s)
- Melanie J Lewis
- Division of Pathology and Neuroscience, University of Dundee Medical School, Ninewells Hospital, Dundee DD19SY, United Kingdom
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10
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Waller A, Flock M, Smith K, Robinson C, Mitchell Z, Karlström A, Lannergård J, Bergman R, Guss B, Flock JI. Vaccination of horses against strangles using recombinant antigens from Streptococcus equi. Vaccine 2007; 25:3629-35. [PMID: 17321016 DOI: 10.1016/j.vaccine.2007.01.060] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Revised: 12/01/2006] [Accepted: 01/11/2007] [Indexed: 12/31/2022]
Abstract
Strangles is an upper respiratory tract infection in horses, which is highly contagious and one of the more costly diseases of the horse. Three recombinant antigens were used to vaccinate horses, which were then experimentally challenged with Streptococcus equi, the causative agent for strangles. The vaccinated horses showed significantly reduced bacterial growth (p=0.02) and nasal discharge (p=0.0004), a typical symptom of strangles. Other clinical signs of strangles were also reduced and at post mortem examination, lower rate of empyaema or scarring of the guttural pouches was found in the vaccinated group (p=0.01). The antigens used were EAG (alpha2-macroglobulin, albumin, and IgG-binding protein), CNE (a collagen-binding protein), and SclC (a collagen-like protein). The adjuvant used was Abisco, a saponin derived matrix. No adverse effects were observed following vaccination with the antigens and adjuvant.
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Waller AS, Jolley KA. Getting a grip on strangles: Recent progress towards improved diagnostics and vaccines. Vet J 2007; 173:492-501. [PMID: 16820310 DOI: 10.1016/j.tvjl.2006.05.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Revised: 05/03/2006] [Accepted: 05/07/2006] [Indexed: 11/29/2022]
Abstract
'Strangles', caused by infection with the bacterium Streptococcus equi, remains one of the most commonly diagnosed and important infectious diseases of horses world-wide. This review discusses the diagnosis and pathogenesis of strangles with particular attention to the significance of persistent infections in disease transmission and the rapid progress now being made towards the development of effective preventative vaccines. It is now possible combine recent sequence data from the N-terminal region of the SeM protein and reassign the SeM alleles using the on-line database http://pubmlst.org/szooepidemicus/seM/. Hypotheses concerning the origin of this variation and the potential for its exploitation for the epidemiological analysis of outbreaks are proposed. Advances in understanding of the molecular evolution of S. equi highlight the role played by phage-mediated acquisition of virulence factors and suggest new avenues for prophylactic intervention.
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Affiliation(s)
- Andrew S Waller
- Centre for Preventive Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, UK.
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Luque I, Fernández-Garayzábal JF, Blume V, Maldonado A, Astorga R, Tarradas C. Molecular Typing and Anti-microbial Susceptibility of Clinical Isolates of Streptococcus equi ssp. zooepidemicus from Equine Bacterial Endometritis. ACTA ACUST UNITED AC 2006; 53:451-4. [PMID: 17062124 DOI: 10.1111/j.1439-0450.2006.01001.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The anti-microbial susceptibility and genetic diversity of 65 strains of Streptococcus equi ssp. zooepidemicus (Sez) isolated from mares presenting clinical signs of endometritis was determined by disk agar diffusion and pulsed field gel electrophoresis (PFGE) methods, respectively. Overall, Sez isolates were susceptible to beta-lactams, enrofloxacin, trimethoprim-sulfamethoxazole and gentamicin. These anti-microbials could be recommended as empiric anti-microbial therapy in cases of endometritis caused by Sez. Pulsed field gel electrophoresis typing revealed a great genetic diversity (56 different PFGE macrorestriction profiles) and a low level of genetic relatedness amongst the isolates.
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Affiliation(s)
- I Luque
- Departamento de Sanidad Animal, Facultad de Veterinaria, Campus Universitario de Rabanales, 14071 Córdoba, Spain.
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Causey RC, Weber JA, Emmans EE, Stephenson LA, Homola AD, Knapp KR, Crowley IF, Pelletier DC, Wooley NA. The equine immune response to Streptococcus equi subspecies zooepidemicus during uterine infection. Vet J 2006; 172:248-57. [PMID: 15950504 DOI: 10.1016/j.tvjl.2005.03.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The purpose of this study was to describe strain-specific immune responses to Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) during uterine infection in horses. Five isolates of S. zooepidemicus were differentiated into four strains antigenically by bactericidal testing in blood of 12 horses, and genetically by pulsed-field gel electrophoresis. Eight healthy mares were then divided into two groups, each inoculated with one strain intrauterinely on three successive oestrous cycles followed by a second strain for three successive cycles, first and second strains being reversed for each group. Immune responses to both strains were assessed by bactericidal testing and immunoblotting over eight cycles. Both techniques indicated that immune responses to each strain arose at different times. Immunoblots showed greater binding to the first inoculated strain than to the second (P < 0.05). These data confirm that immune responses to S. zooepidemicus during uterine infection are partly strain-specific.
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Affiliation(s)
- Robert C Causey
- Department of Animal and Veterinary Sciences and the Maine Agriculture and Forestry Experiment Station, University of Maine, Orono, ME 04469-5735, USA.
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14
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Kelly C, Bugg M, Robinson C, Mitchell Z, Davis-Poynter N, Newton JR, Jolley KA, Maiden MCJ, Waller AS. Sequence variation of the SeM gene of Streptococcus equi allows discrimination of the source of strangles outbreaks. J Clin Microbiol 2006; 44:480-6. [PMID: 16455902 PMCID: PMC1392674 DOI: 10.1128/jcm.44.2.480-486.2006] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2005] [Revised: 10/16/2005] [Accepted: 11/06/2005] [Indexed: 11/20/2022] Open
Abstract
Improved understanding of the epidemiology of Streptococcus equi transmission requires sensitive and portable subtyping methods that can rationally discriminate between strains. S. equi is highly homogeneous and cannot be distinguished by multilocus enzyme electrophoretic or multilocus sequence-typing methods that utilize housekeeping genes. However, on sequence analysis of the N-terminal region of the SeM genes of 60 S. equi isolates from 27 strangles outbreaks, we identified 21 DNA codon changes. These resulted in the nonsynonymous substitution of 18 amino acids and allowed the assignment of S. equi strains to 15 distinct subtypes. Our data suggest the presence of multiple epitopes across this region that are subjected to selective immune pressure (nonsynonymous-synonymous substitution rate [d(N)/d(S)] ratio = 3.054), particularly during the establishment of long-term S. equi infection. We further report the application of SeM gene subtyping as a method to investigate potential cases of disease related to administration of a live attenuated S. equi vaccine. SeM gene subtyping successfully differentiated between the vaccine strain and field strains of S. equi responsible for concurrent disease. These results were confirmed by the development and application of a PCR diagnostic test, which identifies the aroA partial gene deletion present in the Equilis StrepE vaccine strain. Although the vaccine strain was found to be responsible for injection site lesions, all seven outbreaks of strangles investigated in recently vaccinated horses were found to be due to concurrent infection with wild-type S. equi and not due to reversion of the vaccine strain.
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Affiliation(s)
- Charlotte Kelly
- Centre for Preventive Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, United Kingdom
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Lannergård J, Flock M, Johansson S, Flock JI, Guss B. Studies of fibronectin-binding proteins of Streptococcus equi. Infect Immun 2005; 73:7243-51. [PMID: 16239519 PMCID: PMC1273847 DOI: 10.1128/iai.73.11.7243-7251.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2005] [Revised: 04/20/2005] [Accepted: 07/20/2005] [Indexed: 11/20/2022] Open
Abstract
Streptococcus equi subsp. equi is the causative agent of strangles, a disease of the upper respiratory tract in horses. The initiation of S. equi subsp. equi infection is likely to involve cell surface-anchored molecules mediating bacterial adhesion to the epithelium of the host. The present study describes the cloning and characterization of FNEB, a fibronectin-binding protein with cell wall-anchoring motifs. FNEB can thus be predicted as cell surface located, contrary to the two previously characterized fibronectin-binding proteins in S. equi subsp. equi, FNE and SFS. Assays of antibody titers in horses and in experimentally infected mice indicate that the protein is immunogenic and expressed in vivo during S. equi subsp. equi infection. Using Western ligand blotting, it was shown that FNEB binds to the N-terminal 29-kDa fragment of fibronectin, while SFS and FNE both bind to the adjacent 40-kDa fragment. S. equi subsp. equi is known to bind fibronectin to a much lower degree than the closely related S. equi subsp. zooepidemicus, but the binding is primarily directed to the 29-kDa fragment. Inhibition studies using S. equi subsp. equi cells indicate that FNEB mediates cellular binding to fibronectin in this species.
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Affiliation(s)
- Jonas Lannergård
- Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, SE 750 07, Uppsala, Sweden.
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Flock M, Jacobsson K, Frykberg L, Hirst TR, Franklin A, Guss B, Flock JI. Recombinant Streptococcus equi proteins protect mice in challenge experiments and induce immune response in horses. Infect Immun 2004; 72:3228-36. [PMID: 15155624 PMCID: PMC415648 DOI: 10.1128/iai.72.6.3228-3236.2004] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Revised: 02/09/2004] [Accepted: 02/15/2004] [Indexed: 11/20/2022] Open
Abstract
Horses that have undergone infection caused by Streptococcus equi subspecies equi (strangles) were found to have significantly increased serum antibody titers against three previously characterized proteins, FNZ (cell surface-bound fibronectin binding protein), SFS (secreted fibronectin binding protein), and EAG (alpha2-macroglobulin, albumin, and immunoglobulin G [IgG] binding protein) from S. equi. To assess the protective efficacy of vaccination with these three proteins, a mouse model of equine strangles was utilized. Parts of the three recombinant proteins were used to immunize mice, either subcutaneously or intranasally, prior to nasal challenge with S. equi subsp. equi. The adjuvant used was EtxB, a recombinant form of the B subunit of Escherichia coli heat-labile enterotoxin. It was shown that nasal colonization of S. equi subsp. equi and weight loss due to infection were significantly reduced after vaccination compared with a mock-vaccinated control group. This effect was more pronounced after intranasal vaccination than after subcutaneous vaccination; nearly complete eradication of nasal colonization was obtained after intranasal vaccination (P < 0.001). When the same antigens were administered both intranasally and subcutaneously to healthy horses, significant mucosal IgA and serum IgG antibody responses against FNZ and EAG were obtained. The antibody response was enhanced when EtxB was used as an adjuvant. No adverse effects of the antigens or EtxB were observed. Thus, FNZ and EAG in conjunction with EtxB are promising candidates for an efficacious and safe vaccine against strangles.
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Affiliation(s)
- Margareta Flock
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
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Wall T, Roos S, Jacobsson K, Rosander A, Jonsson H. Phage display reveals 52 novel extracellular and transmembrane proteins from Lactobacillus reuteri DSM 20016(T). MICROBIOLOGY-SGM 2004; 149:3493-3505. [PMID: 14663082 DOI: 10.1099/mic.0.26530-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Extracellular and transmembrane proteins are important for the binding of bacteria to intestinal surfaces and for their interaction with the host. The aim of this study was to identify genes encoding extracellular and transmembrane proteins from the probiotic bacterium Lactobacillus reuteri by construction and screening of a phage display library. This library was constructed by insertion of randomly fragmented DNA from L. reuteri into the phagemid vector pG3DSS, which was previously developed for screening for extracellular proteins. After affinity selection of the library, the L. reuteri inserts were sequenced and analysed with bioinformatic tools. The screening resulted in the identification of 52 novel genes encoding extracellular and transmembrane proteins. These proteins were classified as: transport proteins; enzymes; sensor-regulator proteins; proteins involved in host/microbial interactions; conserved hypothetical proteins; and unconserved hypothetical proteins. Further characterization of the extracellular and transmembrane proteins identified should contribute to the understanding of the probiotic properties of L. reuteri.
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Affiliation(s)
- Torun Wall
- Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, SE-750 07 Uppsala, Sweden
| | - Stefan Roos
- Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, SE-750 07 Uppsala, Sweden
| | - Karin Jacobsson
- Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, SE-750 07 Uppsala, Sweden
| | - Anna Rosander
- Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, SE-750 07 Uppsala, Sweden
| | - Hans Jonsson
- Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, SE-750 07 Uppsala, Sweden
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Slater JD. Strangles, bastard strangles, vives and glanders: archaeological relics in a genomic age. Equine Vet J 2003; 35:118-20. [PMID: 12638785 DOI: 10.2746/042516403776114252] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Harrington DJ, Sutcliffe IC, Chanter N. The molecular basis of Streptococcus equi infection and disease. Microbes Infect 2002; 4:501-10. [PMID: 11932201 DOI: 10.1016/s1286-4579(02)01565-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Streptococcus equi is the aetiological agent of strangles, one of the most prevalent diseases of the horse. The animal suffering and economic burden associated with this disease necessitate effective treatment. Current antibiotic therapy is often ineffective and thus recent attention has focused on vaccine development. A systematic understanding of S. equi virulence, leading to the identification of targets to which protective immunity can be directed, is a prerequisite of the development of such a vaccine. Here, the virulence factors of S. equi are reviewed.
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Affiliation(s)
- Dean J Harrington
- Department of Biomedical Sciences, University of Bradford, West Yorkshire, BD7 1DP, UK.
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Meehan M, Lynagh Y, Woods C, Owen P. The fibrinogen-binding protein (FgBP) of Streptococcus equi subsp. equi additionally binds IgG and contributes to virulence in a mouse model. MICROBIOLOGY (READING, ENGLAND) 2001; 147:3311-22. [PMID: 11739763 DOI: 10.1099/00221287-147-12-3311] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The major cell-wall-associated protein of the equine pathogen Streptococcus equi subsp. equi is an M-like fibrinogen-binding protein (FgBP) which binds equine fibrinogen (Fg) avidly, through residues located at the extreme N-terminus of the molecule. In this study, it is shown that FgBP additionally binds equine IgG-Fc. When tested against polyclonal IgG from ten other animal species, it was found that FgBP binds human, rabbit, pig and cat IgG, but does not bind mouse, rat, goat, sheep, cow or chicken IgG. Through the use of a panel of recombinant FgBP truncates containing defined deletions of sequence, it was shown that residues in the central regions of FgBP are important in IgG binding. An fbp knockout mutant which does not express FgBP on the cell surface was also constructed. Mutant cells failed to autoaggregate, bound no detectable equine Fg or IgG-Fc, were rapidly killed in horse blood, and showed greatly decreased virulence in a mouse model. Results suggest that FgBP is the major surface structure responsible for binding either Fg or IgG, that the molecule has pronounced antiphagocytic properties, and that it is a likely factor contributing to the virulence of wild-type S. equi subsp. equi.
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Affiliation(s)
- M Meehan
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland
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Lindmark H, Nilsson M, Guss B. Comparison of the fibronectin-binding protein FNE from Streptococcus equi subspecies equi with FNZ from S. equi subspecies zooepidemicus reveals a major and conserved difference. Infect Immun 2001; 69:3159-63. [PMID: 11292736 PMCID: PMC98272 DOI: 10.1128/iai.69.5.3159-3163.2001] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2000] [Accepted: 02/09/2001] [Indexed: 11/20/2022] Open
Abstract
The gene fnz from Streptococcus equi subspecies zooepidemicus encodes a cell surface protein that binds fibronectin (Fn). Fifty tested isolates of S. equi subspecies equi all contain DNA sequences with similarity to fnz. This work describes the cloning and sequencing of a gene, designated fne, with similarity to fnz from two S. equi subspecies equi isolates. The DNA sequences were found to be identical in the two strains, and sequence comparison of the fne and fnz genes revealed only minor differences. However, one base deletion was found in the middle of the fne gene and eight base pairs downstream of the altered reading frame there is a stop codon. An Fn-binding protein was purified from the growth medium of a subspecies equi culture. Determination of the NH(2)-terminal amino acid sequence and molecular mass, as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, revealed that the purified protein is the gene product of the 5'-terminal half of fne. Fn-binding activity has earlier only been found in the COOH-terminal half of FNZ. By the use of a purified recombinant protein containing the NH(2) half of FNZ, we provide here evidence that this half of the protein also harbors an Fn-binding domain.
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Affiliation(s)
- H Lindmark
- Department of Microbiology, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden
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Schott HC, Ewart SL, Walker RD, Dwyer RM, Dietrich S, Eberhart SW, Kusey J, Stick JA, Derksen FJ. An outbreak of salmonellosis among horses at a veterinary teaching hospital. J Am Vet Med Assoc 2001; 218:1152-9, 1100. [PMID: 11318368 DOI: 10.2460/javma.2001.218.1152] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Between May 1996 and February 1997, 27 horses and a veterinary student at a veterinary teaching hospital developed apparent nosocomial Salmonella Typhimurium infection. The source of the multiple-drug resistant Salmonella Typhimurium was a neonatal foal admitted for treatment of septicemia. A high infection rate (approx 13% of hospitalized horses) coupled with a high case fatality rate (44%) for the initial 18 horses affected led to a decision to close the hospital for extensive cleaning and disinfection. Despite this effort and modification of hospital policies for infection control, 9 additional horses developed nosocomial Salmonella Typhimurium infection during the 6 months after the hospital reopened. Polymerase chain reaction testing of environmental samples was useful in identifying a potential reservoir of the organism in drains in the isolation facility. Coupled with clinical data, comparison of antimicrobial resistance patterns of Salmonella Typhimurium isolates provided a rapid initial means to support or refute nosocomial infection. Although minor changes in the genome of these isolates developed over the course of the outbreak, pulsed-field gel electrophoresis testing further supported that salmonellosis was nosocomial in all 27 horses.
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Affiliation(s)
- H C Schott
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824-1314, USA
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Lindmark H, Guss B. SFS, a novel fibronectin-binding protein from Streptococcus equi, inhibits the binding between fibronectin and collagen. Infect Immun 1999; 67:2383-8. [PMID: 10225899 PMCID: PMC115982 DOI: 10.1128/iai.67.5.2383-2388.1999] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1998] [Accepted: 02/20/1999] [Indexed: 11/20/2022] Open
Abstract
The obligate parasitic bacterium Streptococcus equi subsp. equi is the causative agent of strangles, a serious disease of the upper respiratory tract in horses. In this study we have, using shotgun phage display, cloned from S. equi subsp. equi and characterized a gene, called sfs, encoding a protein termed SFS, representing a new type of fibronectin (Fn)-binding protein. The sfs gene was found to be present in all 50 isolates of S. equi subsp. equi tested and in 41 of 48 S. equi subsp. zooepidemicus isolates tested. The sfs gene is down-regulated during growth in vitro compared to fnz, a previously characterized gene encoding an Fn-binding protein from S. equi subsp. zooepidemicus. Sequence comparisons revealed no similarities to previously characterized Fn-binding proteins, but high scores were obtained against collagen. Besides similarity due to the high content of glycine, serine, and proline residues present in both proteins, there was a nine-residue motif present both in collagen and in the Fn-binding domain of SFS. By searching the Oklahoma S. pyogenes database, we found that this motif is also present in a potential cell surface protein from S. pyogenes. Protein SFS was found to inhibit the binding between Fn and collagen in a concentration-dependent way.
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Affiliation(s)
- H Lindmark
- Department of Microbiology, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden
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