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Li S, Xu G, Guo Z, Liu Y, Ouyang Z, Li Y, Huang Y, Sun Q, Giri BR, Fu Q. Deficiency of hasB accelerated the clearance of Streptococcus equi subsp. Zooepidemicus through gasdermin d-dependent neutrophil extracellular traps. Int Immunopharmacol 2024; 140:112829. [PMID: 39083933 DOI: 10.1016/j.intimp.2024.112829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Revised: 07/23/2024] [Accepted: 07/26/2024] [Indexed: 08/02/2024]
Abstract
Streptococcus equi subsp. zooepidemicus (S. zooepidemicus, SEZ) is an essential zoonotic bacterial pathogen that can cause various inflammation, such as meningitis, endocarditis, and pneumonia. UDP-glucose dehydrogenase (hasB) is indispensable in synthesizing SEZ virulence factor hyaluronan capsules. Our study investigated the infection of hasB on mice response to SEZ by employing a constructed capsule-deficient mutant strain designated as the ΔhasB strain. This deficiency was associated with a reduced SEZ bacterial load in the mice's blood and peritoneal lavage fluid (PLF) post-infection. Besides, the ΔhasB SEZ strain exhibited a higher propensity for neutrophil infiltration and release of cell-free DNA (cfDNA) in vivo compared to the wild-type (WT) SEZ strain. In vitro experiments further revealed that ΔhasB SEZ more effectively induced the formation of neutrophil extracellular traps (NETs) containing histone 3 (H3), neutrophil elastase (NE), and DNA, than its WT counterpart. Moreover, the release of NETs was determined to be gasdermin D (GSDMD)-dependent during the infection process. Taken together, these findings underscore that the deficiency of the hasB gene in SEZ leads to enhanced GSDMD-dependent NET release from neutrophils, thereby reducing SEZ's capacity to resist NETs-mediated eradication during infection. Our finding paves the way for the development of innovative therapeutic strategies against SEZ.
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Affiliation(s)
- Shun Li
- School of Life Science and Engineering, Foshan University, Foshan, Guangdong, China; Foshan University Veterinary Teaching Hospital, Foshan University, Foshan, Guangdong, China
| | - Guobin Xu
- School of Life Science and Engineering, Foshan University, Foshan, Guangdong, China
| | - Zheng Guo
- School of Life Science and Engineering, Foshan University, Foshan, Guangdong, China
| | - Yuxuan Liu
- School of Life Science and Engineering, Foshan University, Foshan, Guangdong, China
| | - Zhiliang Ouyang
- Houjie Town Agricultural Technology Service Center, Dongguan, Guangdong, China
| | - Yajuan Li
- School of Life Science and Engineering, Foshan University, Foshan, Guangdong, China; Foshan University Veterinary Teaching Hospital, Foshan University, Foshan, Guangdong, China
| | - Yunfei Huang
- School of Life Science and Engineering, Foshan University, Foshan, Guangdong, China; Foshan University Veterinary Teaching Hospital, Foshan University, Foshan, Guangdong, China
| | - Qinqin Sun
- School of Life Science and Engineering, Foshan University, Foshan, Guangdong, China; Foshan University Veterinary Teaching Hospital, Foshan University, Foshan, Guangdong, China
| | - Bikash R Giri
- Department of Zoology, K.K.S. Women's College, Balasore, Odisha, India
| | - Qiang Fu
- School of Life Science and Engineering, Foshan University, Foshan, Guangdong, China; Foshan University Veterinary Teaching Hospital, Foshan University, Foshan, Guangdong, China.
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2
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Li Y, Zhang P, Huang Y, Yu J, Liu Y, Li S, Sun Q, Fu Q. SzM protein of Streptococcus equi ssp. zooepidemicus triggers the release of neutrophil extracellular traps depending on GSDMD. Microb Pathog 2024; 192:106703. [PMID: 38763315 DOI: 10.1016/j.micpath.2024.106703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 05/05/2024] [Accepted: 05/15/2024] [Indexed: 05/21/2024]
Abstract
Streptococcus equissp.zooepidemicus (SEZ) is a crucial pathogen and contributes to various infections in numerous animal species. Swine streptococcicosis outbreak caused by SEZ has been reported in several countries in recent years. SzM protein is a cell membrane-anchored protein, which exhibits as an important virulence factor of SEZ. Effects of SzM protein on host innate immune need further study. Here, recombinant SzM (rSzM) protein of the SEZ was obtained, and mice were intraperitoneally injected with rSzM protein. We discovered that rSzM protein can recruit neutrophils into the injected site. In further study, neutrophils were isolated and treated with rSzM protein, NETs release were triggered by rSzM protein independently, and GSDMD protein was promoted-expressed and activated. In order to investigate the role of GSDMD in NETs formation, neutrophils isolated from WT mice and GSDMD-/- mice were treated with rSzM protein. The results showed that GSDMD deficiency suppressed the NETs release. In conclusion, SzM protein of SEZ can trigger the NETs release in a GSDMD-depending manner.
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Affiliation(s)
- Yajuan Li
- School of Life Science and Engineering, Foshan University, Guangdong, 528225, China; Foshan University Veterinary Teaching Hospital, Foshan University, Guangdong, 528225, China
| | - Pengju Zhang
- School of Life Science and Engineering, Foshan University, Guangdong, 528225, China
| | - Yunfei Huang
- School of Life Science and Engineering, Foshan University, Guangdong, 528225, China; Foshan University Veterinary Teaching Hospital, Foshan University, Guangdong, 528225, China
| | - Jingyu Yu
- School of Life Science and Engineering, Foshan University, Guangdong, 528225, China
| | - Yuxuan Liu
- School of Life Science and Engineering, Foshan University, Guangdong, 528225, China
| | - Shun Li
- School of Life Science and Engineering, Foshan University, Guangdong, 528225, China; Foshan University Veterinary Teaching Hospital, Foshan University, Guangdong, 528225, China
| | - Qinqin Sun
- School of Life Science and Engineering, Foshan University, Guangdong, 528225, China; Foshan University Veterinary Teaching Hospital, Foshan University, Guangdong, 528225, China
| | - Qiang Fu
- School of Life Science and Engineering, Foshan University, Guangdong, 528225, China; Foshan University Veterinary Teaching Hospital, Foshan University, Guangdong, 528225, China.
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3
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Li Y, Lin Z, Yu J, Liu Y, Li S, Huang Y, Ayodele Olaolu O, Fu Q. Neutrophil accumulation raises defence against Streptococcus equi ssp. zooepidemicus in the absence of Gasdermin D. Int Immunopharmacol 2024; 131:111891. [PMID: 38498953 DOI: 10.1016/j.intimp.2024.111891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 03/11/2024] [Accepted: 03/14/2024] [Indexed: 03/20/2024]
Abstract
Streptococcus equi ssp. zooepidemicus (SEZ) predominantly acts as a zoonotic pathogen, capable of infecting a diverse range of animal species including human. Gasdermin D (GSDMD) exhibited comprehensive functions in host against different pathogenic microorganism. This study aimed to investigate the role of GSDMD in host against SEZ. Mice were administrated with SEZ via intranasal intubation for 24 h (3 × 106CFU), GSDMD protein expression significantly increased in the lung tissue of mice infected with SEZ. For further research on the role of GSDMD during SEZ infection, GSDMD-/- mice and WT mice were treated with SEZ via intranasal intubation for 24 h (3 × 106CFU). GSDMD-/- mice showed less severe lung tissue due to fewer bacteria colonization. Numerous neutrophils were recruited into lung tissues in GSDMD-/- mice, related to the release of CXCL1 and CXCL2 regulated by p65 phosphorylation. In further study, neutrophils of WT and GSDMD-/- mice were isolated and treated with SEZ (multiplicity of infection, MOI = 10, 4 h). The absence of GSDMD alleviated the death of neutrophils, in addition, GSDMD deficiency could promote translocation of p65 from the cytoplasm into the nucleus in neutrophil, which may contribute to the release of IL-1β and TNF-α. This study demonstrated a novel function of GSDMD in host immune response to SEZ invading, indicating that GSDMD deficiency ameliorated SEZ infection through enhancing neutrophil accumulation into infected site, and activating NF-κB pathway in neutrophil to release cytokines against SEZ. Our study suggested that inhibition of host GSDMD may be an effective method against SEZ.
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Affiliation(s)
- Yajuan Li
- School of Life Science and Engineering, Foshan University, Guangdong, China; Foshan University Veterinary Teaching Hospital, Foshan University, Guangdong, China
| | - Zihua Lin
- School of Life Science and Engineering, Foshan University, Guangdong, China
| | - Jingyu Yu
- School of Life Science and Engineering, Foshan University, Guangdong, China
| | - Yuxuan Liu
- School of Life Science and Engineering, Foshan University, Guangdong, China
| | - Shun Li
- School of Life Science and Engineering, Foshan University, Guangdong, China; Foshan University Veterinary Teaching Hospital, Foshan University, Guangdong, China
| | - Yunfei Huang
- School of Life Science and Engineering, Foshan University, Guangdong, China; Foshan University Veterinary Teaching Hospital, Foshan University, Guangdong, China
| | - Oladejo Ayodele Olaolu
- Department of Animal Health Technology, Oyo State College of Agriculture and Technolog Igboor, Igboora, Nigeria
| | - Qiang Fu
- School of Life Science and Engineering, Foshan University, Guangdong, China; Foshan University Veterinary Teaching Hospital, Foshan University, Guangdong, China.
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4
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Liu Y, Lu M, Sun Q, Guo Z, Lin Y, Li S, Huang Y, Li Y, Fu Q. Magnolol attenuates macrophage pyroptosis triggered by Streptococcus equi subsp. zooepidemicus. Int Immunopharmacol 2024; 131:111922. [PMID: 38522137 DOI: 10.1016/j.intimp.2024.111922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 12/11/2023] [Accepted: 03/21/2024] [Indexed: 03/26/2024]
Abstract
Streptococcus equi subsp. zooepidemicus (SEZ) is a zoonotic bacterial pathogen that causes life-threatening infections and various diseases such as meningitis, endocarditis and pneumonia. With the use of antibiotics being severely restricted in the international community, an alternative to antibiotics is urgently needed against bacterial. In the present study, the herbal extract magnolol protected mice against SEZ infection, reflected by increased survival rate and reduced bacterial burden. A pro-inflammatory form of cell death occurred in SEZ-infected macrophage. Magnolol downregulated the expression of pyroptosis-related proteins and reduced the formation of cell membrane pores in infected macrophages to suppress the development of subsequent inflammation. We further demonstrated that magnolol directly suppressed SEZ-induced macrophage pyroptosis, which partially protected macrophages from SEZ infection. Our study revealed that magnolol suppressed inflammation and protected mice against SEZ infection, providing a possible treatment for SEZ infection.
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Affiliation(s)
- Yuxuan Liu
- School of Life Science and Engineering, Foshan University, Foshan, China
| | - Meijun Lu
- School of Life Science and Engineering, Foshan University, Foshan, China
| | - Qian Sun
- School of Life Science and Engineering, Foshan University, Foshan, China
| | - Zheng Guo
- School of Life Science and Engineering, Foshan University, Foshan, China
| | - Yongjin Lin
- School of Life Science and Engineering, Foshan University, Foshan, China
| | - Shun Li
- School of Life Science and Engineering, Foshan University, Foshan, China; Foshan University Veterinary Teaching Hospital, Foshan University, Foshan, China
| | - Yunfei Huang
- School of Life Science and Engineering, Foshan University, Foshan, China; Foshan University Veterinary Teaching Hospital, Foshan University, Foshan, China
| | - Yajuan Li
- School of Life Science and Engineering, Foshan University, Foshan, China; Foshan University Veterinary Teaching Hospital, Foshan University, Foshan, China.
| | - Qiang Fu
- School of Life Science and Engineering, Foshan University, Foshan, China; Foshan University Veterinary Teaching Hospital, Foshan University, Foshan, China.
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Xie H, Zhang R, Guo R, Zhang Y, Zhang J, Li H, Fu Q, Wang X. Characterization of AI-2/LuxS quorum sensing system in biofilm formation, pathogenesis of Streptococcus equi subsp. zooepidemicus. Front Cell Infect Microbiol 2024; 14:1339131. [PMID: 38379770 PMCID: PMC10876813 DOI: 10.3389/fcimb.2024.1339131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/24/2024] [Indexed: 02/22/2024] Open
Abstract
Streptococcus equi subsp. zooepidemicus (SEZ) is an opportunistic pathogen of both humans and animals. Quorum sensing (QS) plays an important role in the regulation of bacterial group behaviors. The aim of this study was to characterize the LuxS in SEZ and evaluate its impact on biofilm formation, pathogenesis and gene expression. The wild-type SEZ and its LuxS mutant (ΔluxS) were examined for growth, biofilm formation, virulence factors, and transcriptomic profiles. Our results showed that LuxS deficiency did not affect SEZ hemolytic activity, adhesion or capsule production. For biofilm assay demonstrated that mutation in the luxS gene significantly enhances biofilm formation, produced a denser biofilm and attached to a glass surface. RAW264.7 cell infection indicated that ΔluxS promoted macrophage apoptosis and pro-inflammatory responses. In mice infection, there was no significant difference in mortality between SEZ and ΔluxS. However, the bacterial load in the spleen of mice infected with ΔluxS was significantly higher than in those infected with SEZ. And the pathological analysis further indicated that spleen damage was more severe in the ΔluxS group. Moreover, transcriptomics analysis revealed significant alterations in carbon metabolism, RNA binding and stress response genes in ΔluxS. In summary, this study provides the first evidence of AI-2/LuxS QS system in SEZ and reveals its regulatory effects on biofilm formation, pathogenicity and gene expression.
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Affiliation(s)
- Honglin Xie
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Riteng Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Ruhai Guo
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Yining Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Jingya Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Hui Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Qiang Fu
- School of Life Science and Engineering, Foshan University, Foshan, China
| | - Xinglong Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
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Geiping L, Detlefsen H, Trittmacher S, Baums CG, Bergmann R, Hennig-Pauka I. Streptococcus equi subspecies zooepidemicus - a case report of sudden death in a German sow farm. Porcine Health Manag 2023; 9:48. [PMID: 37875963 PMCID: PMC10594803 DOI: 10.1186/s40813-023-00344-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 10/16/2023] [Indexed: 10/26/2023] Open
Abstract
A farm in North-West Germany experienced a high morbidity and mortality in their sow herd. Sows showed fever, lethargy, oedema, mucosal discharge and dyspnoea. Necropsy revealed a severe fibrinous and purulent polyserositis. Haematological and histological examinations confirmed septicaemia. Streptococcus equi subspecies zooepidemicus was isolated in high yields from major organs. Sequence typing of this isolate (21/455) revealed a new sequence type showing a significantly higher proliferation rate in comparison to two other isolates. Other infectious agents (influenza A virus, Porcine Reproductive and Respiratory Syndrome Virus, Porcine Circovirus 2, african swine fever virus, classical swine fever virus, Actinobacillus pleuropneumoniae) were excluded by routine diagnostic examinations. A climate check revealed an insufficient air supply in the area for the gestating sows. This case describes the first disease outbreak in swine due to S. zooepidemicus in Germany.
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Affiliation(s)
- Lukas Geiping
- Field Station for Epidemiology in Bakum, University of Veterinary Medicine Hannover, Foundation, Germany
| | - Henrik Detlefsen
- Tierarztpraxis Bethen, Heideweg 7, 49661, Cloppenburg/Bethen, Germany
| | - Sara Trittmacher
- Field Station for Epidemiology in Bakum, University of Veterinary Medicine Hannover, Foundation, Germany
| | - Christoph Georg Baums
- Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - René Bergmann
- Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Isabel Hennig-Pauka
- Field Station for Epidemiology in Bakum, University of Veterinary Medicine Hannover, Foundation, Germany.
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Pan F, Zhu M, Liang Y, Yuan C, Zhang Y, Wang Y, Fan H, Waldor MK, Ma Z. Membrane vesicle delivery of a streptococcal M protein disrupts the blood-brain barrier by inducing autophagic endothelial cell death. Proc Natl Acad Sci U S A 2023; 120:e2219435120. [PMID: 37276410 PMCID: PMC10268326 DOI: 10.1073/pnas.2219435120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 05/08/2023] [Indexed: 06/07/2023] Open
Abstract
M family proteins are critical virulence determinants of Streptococci. Streptococcus equi subsp. zooepidemicus (SEZ) are Group C streptococci that cause meningitis in animals and humans. SzM, the M protein of SEZ, has been linked to SEZ brain invasion. Here, we demonstrate that SzM is important in SEZ disruption of the blood-brain barrier (BBB). SEZ release SzM-bound membrane vesicles (MVs), and endocytosis of these vesicles by human brain endothelial microvascular cells (hBMECs) results in SzM-dependent cytotoxicity. Furthermore, administration of SzM-bound MVs disrupted the murine BBB. A CRISPR screen revealed that SzM cytotoxicity in hBMECs depends on PTEN-related activation of autophagic cell death. Pharmacologic inhibition of PTEN activity prevented SEZ disruption of the murine BBB and delayed mortality. Our data show that MV delivery of SzM to host cells plays a key role in SEZ pathogenicity and suggests that MV delivery of streptococcal M family proteins is likely a common streptococcal virulence mechanism.
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Affiliation(s)
- Fei Pan
- Ministry of Agriculture Key Laboratory of Animal Bacteriology, the International Joint Laboratory of Animal Health and Food Safety, and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu210095, China
| | - Mingli Zhu
- Ministry of Agriculture Key Laboratory of Animal Bacteriology, the International Joint Laboratory of Animal Health and Food Safety, and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu210095, China
| | - Ying Liang
- Ministry of Agriculture Key Laboratory of Animal Bacteriology, the International Joint Laboratory of Animal Health and Food Safety, and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu210095, China
| | - Chen Yuan
- Ministry of Agriculture Key Laboratory of Animal Bacteriology, the International Joint Laboratory of Animal Health and Food Safety, and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu210095, China
| | - Yu Zhang
- Ministry of Agriculture Key Laboratory of Animal Bacteriology, the International Joint Laboratory of Animal Health and Food Safety, and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu210095, China
| | - Yuchang Wang
- Ministry of Agriculture Key Laboratory of Animal Bacteriology, the International Joint Laboratory of Animal Health and Food Safety, and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu210095, China
| | - Hongjie Fan
- Ministry of Agriculture Key Laboratory of Animal Bacteriology, the International Joint Laboratory of Animal Health and Food Safety, and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu210095, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou225009, China
| | - Matthew K. Waldor
- HHMI, Boston, MA02115
- Brigham and Women’s HospitalDivision of Infectious Diseases, Boston, MA02115
- Department of Microbiology, Harvard Medical School, Boston, MA02115
| | - Zhe Ma
- Ministry of Agriculture Key Laboratory of Animal Bacteriology, the International Joint Laboratory of Animal Health and Food Safety, and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu210095, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou225009, China
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Outbreak of Pathogenic Streptococcus equi subsp. zooepidemicus in Guinea Pigs Farms of The Andean Region. Pathogens 2023; 12:pathogens12030445. [PMID: 36986367 PMCID: PMC10055897 DOI: 10.3390/pathogens12030445] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/25/2023] [Accepted: 03/09/2023] [Indexed: 03/14/2023] Open
Abstract
Streptococcus zooepidemicus is an emerging zoonotic pathogen involved in septicemic infections in humans and livestock. Raising guinea pigs in South America is an important economic activity compared to raising them as pets in other countries. An outbreak of severe lymphadenitis was reported in guinea pigs from farms in the Andean region. S. zooepidemicus was isolated from multiple cervical and mandibular abscesses. Isolate was characterized by multilocus sequence typing and phylogenetic analysis. This is the first molecular characterization of a highly pathogenic strain, showing major important virulence factors such as the M-like protein genes szP and mlpZ, the fimbrial subunit protein gene fszF, and the protective antigen-like protein gene spaZ. Additionally, this guinea pig strain was phylogenetically related to equines but distant from zoonotic and pig isolates reported in other countries.
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9
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Protection Efficacy of Monoclonal Antibodies Targeting Different Regions of Specific SzM Protein from Swine-Isolated Streptococcus equi ssp. zooepidemicus Strains. Microbiol Spectr 2022; 10:e0174222. [PMID: 36255327 PMCID: PMC9769693 DOI: 10.1128/spectrum.01742-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Streptococcus equi subsp. zooepidemicus (SEZ) has a wide host spectrum, including humans and domestic animals. The SEZ-caused swine streptococcicosis outbreak has occurred in several countries, and the swine-isolated strains usually have specific S. zooepidemicus M-like (szm) gene types. In this study, we found that the production of this specific szm gene (SzM protein) was an effective vaccine candidate. It could provide better protection with a 7-day interval immune procedure than the traditional vaccine strain ST171 and attenuate the strain ΔsezV against swine-isolated hypervirulent SEZ infections. According to this outcome, we developed monoclonal antibodies (McAbs) targeting the variable and conserved regions of this SzM protein, respectively. These McAbs all belong to the IgG1 isotype with a κ type light chain and have opsonophagocytic activity rather than agglutination or complement activation functions. We estimated the protection efficiency of the McAbs with 3 different passive immunotherapy programs. The anti-conserved region McAb can provide effective protection against swine-isolated SEZ infections with only the inconvenient immunotherapy program. It also partially works in preventing infection by other SEZ strains. In contrast, the anti-variable region McAb is only adapted to protect the host against a specific szm type SEZ strain isolated from pigs, but it is flexible for different immunotherapy programs. These data provide further information to guide the development of derived, genetically engineered McAbs that have potential applications in protecting hosts against swine-isolated, hypervirulent SEZ infections in the future. IMPORTANCE The swine-isolated SEZ, with its specific szm gene sequence, has impacted the pig feeding industry in China and North America and has led to serious economic loss. Though the SzM protein of SEZ has been proven to be an effective vaccine in preventing infection, most previous studies focused on horse-isolated strains, which have different szm gene types compared to swine-isolated strains. In this study, we developed the McAbs targeting the conserved and variable regions of this SzM protein from the swine-isolated hypervirulent strains and evaluated their protection efficiency. Our research provided information for the development of chimeric McAbs or other genetically engineered McAbs that have potential applications in protecting pigs against hypervirulent SEZ infections in the future.
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10
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Costa MDO, Harding JCS, Huang Y, Nosach R. Streptococcus equi subsp. zooepidemicus infection of pigs leads to shedding in faeces and a carrier state. Transbound Emerg Dis 2022; 69:e1503-e1509. [PMID: 35182443 PMCID: PMC9790520 DOI: 10.1111/tbed.14481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 02/09/2022] [Accepted: 02/13/2022] [Indexed: 12/30/2022]
Abstract
In 2019, Streptococcus equi subsp. zooepidemicus was recognized as an emerging pathogen of swine, associated with sudden deaths, increased abortion rates and septicaemia. Limited data are available regarding this disease in pigs. The objectives of this study were to clarify clinical progression, pathogen shedding, transmission, gross and microscopic lesions following infection in pigs. Six weeks old pigs were inoculated with either S. zooepidemicus sequence type 194 (inoculated, n = 6) or sham inoculated with sterile culture broth (sentinels, n = 4). Animals were housed in the same room, in two pens 2 m apart. Pigs were monitored twice daily for clinical signs, and rectal, nasal and oral swabs were collected once daily. A full necropsy was performed if welfare was a concern or at 5 days post-inoculation (dpi). All sentinels remained disease free and their samples tested negative for the pathogen of interest. All inoculated pigs developed fever within 8 h of inoculation, and severe disease was observed after 2 dpi. A total of 4/6 inoculated pigs developed clinical signs that compromised animal welfare and were euthanized. Nasal swabs (15/23), followed by rectal swabs (9/23) yield the highest number of positive ante-mortem samples. Clinically healthy, inoculated pigs had detectable levels of S. zooepidemicus in rectal and nasal swabs. Reactive submandibular lymph nodes, kidney petechiae and splenomegaly were found in six of six inoculated pigs. These data suggest that subclinically infected pigs may spread the pathogen through nasal secretions and faeces. Direct contact seems to be required for transmission.
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Affiliation(s)
- Matheus de Oliveira Costa
- Department of Large Animal Clinical SciencesWestern College of Veterinary MedicineUniversity of SaskatchewanSaskatoonCanada,Department of Population HealthFaculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
| | - John Clare Samuel Harding
- Department of Large Animal Clinical SciencesWestern College of Veterinary MedicineUniversity of SaskatchewanSaskatoonCanada
| | | | - Roman Nosach
- Department of Large Animal Clinical SciencesWestern College of Veterinary MedicineUniversity of SaskatchewanSaskatoonCanada
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11
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Lin Z, Xia Y, Guo J, Xu G, Liu Y, Yang Y, Xie H, Huang Y, Fu Q. Caspase-1 deficiency impairs neutrophils recruitment and bacterial clearance in Streptococcus equi ssp. zooepidemicus infected mice. Vet Microbiol 2022; 268:109411. [DOI: 10.1016/j.vetmic.2022.109411] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 03/08/2022] [Accepted: 03/26/2022] [Indexed: 11/27/2022]
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12
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Hau SJ, Buckley A, Brockmeier SL. Bacterin Vaccination Provides Insufficient Protection Against Streptococcus equi Subspecies zooepidemicus Infection in Pigs. Front Vet Sci 2022; 9:827082. [PMID: 35296061 PMCID: PMC8918573 DOI: 10.3389/fvets.2022.827082] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/18/2022] [Indexed: 11/13/2022] Open
Abstract
Streptococcus equi subspecies zooepidemicus (SEZ) is a zoonotic pathogen capable of causing severe disease in many mammalian species. Historically, SEZ has not been a common cause of disease in pigs in North America; however, in 2019, SEZ caused mortality events leading to severe illness and 30–50% mortality in exposed animal groups. Because of the rapid progression of disease, it is important to investigate intervention strategies to prevent disease development. In this study, pigs were divided into four groups: (1) vaccinated with an inactivated SEZ vaccine generated from a highly mucoid 2019 mortality event isolate; (2) vaccinated with an inactivated SEZ vaccine generated from a genetically similar, non-mucoid isolate from a guinea pig; (3) and (4) sham vaccinated. Following boost vaccination, groups 1–3 were challenged with a 2019 mortality event isolate and group 4 were non-challenged controls. Antibody titers were higher for SEZ vaccinated animals than sham vaccinated animals; however, no anamnestic response was observed, and titers were lower than typically seen following the use of inactivated vaccines. Vaccination did not provide protection from disease development or mortality following challenge, which could be associated with the comparatively low antibody titers generated by vaccination. Surviving pigs also remained colonized and transmitted SEZ to naïve contact pigs 3 weeks following challenge, indicating that healthy animals can act as a source of SEZ exposure. Future investigation should evaluate different vaccine formulations, such as increased antigen load or an alternative adjuvant, that could induce a more robust adaptive immune response.
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