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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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Strangles, caused by Streptococcus equi subspecies equi, is a highly infectious respiratory disease affecting horses and other equines. The disease is economically important and compromises the productivity of equine farm significantly. The disease is characterized by pyrexia, mucopurulent nasal discharge, and abscess formation in the lymph nodes of the head and neck of horses. The disease transmission occurs either directly by coming in contact with infectious exudates or indirectly via fomite transmission. Besides this, carrier animals are the primary and most problematic source of disease infection. The organism not only initiates outbreaks but also makes the control and prevention of the disease difficult. The diagnosis of strangles is best done by isolating and characterizing the bacteria from nasal discharge, pus from abscesses, and lymphoid tissues or by using PCR. ELISA can also be used to detect serum protein M (SeM) antibodies for diagnosis. The most popular treatment for strangles is with penicillin; however, the treatment is affected by the stage, feature and severity of the disease. Prevention and control of strangles can be achieved through vaccination and good hygiene practices. Basically, this review describes the global prevalence of S. equi, as well as general aspects of the disease, like pathogenesis, diagnosis, treatment, prevention, control and management of the disease., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) causes a wide variety of infections in many species. CD44 is a transmembrane adhesion molecule, expressed by various cell types, which has been implicated in several infection processes. The aim of this study was to examine the role of CD44 in S. zooepidemicus adherence to LA-4 cells (mouse lung adenoma). Dose-dependent adhesion with LA-4 may be effectively studied by flow cytometry. Adherence of S. zooepidemicus is reduced after treatment of cells with anti-CD44 antibody. Treatment of S. zooepidemicus with recombinant CD44 significantly reduced bacteria adherence. In addition, CD44 can directly bind to wild-type S. zooepidemicus, while the binding was decreased in the capsule deletion isogenic mutant. These data suggest that CD44 facilitates adherence of S. zooepidemicus to LA-4 cells., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Infection with Streptococcus equi ssp. zooepidemicus (Streptococcus zooepidemicus, SEZ) can cause septicemia, meningitis, and mastitis in domesticated species. Identification of this organism's virulence factors is an effective way of clarifying its pathogenic mechanism. We employed in vivo-induced antigen technology (IVIAT) to find bacterial genes that were only expressed or upregulated in an infected host (IVI genes). Convalescent-phase sera from pigs infected with SEZ were pooled, adsorbed against in vitro antigens, and used to screen SEZ genomic expression libraries. This analysis identified 43 genes as IVI genes. Six of these 43 genes were verified via real-time PCR. Following the analysis, we were able to assign a putative function to 36 of the 43 proteins. These proteins included those involved in virulence and adaptation; formation of intermediary products; gene replication, transcription and expression; energy metabolism; transport and also various proteins of unknown function. The relationship between sagD gene and bacterial virulence was confirmed. This study provides new molecular data for the study of streptococcal disease in swine and is important for identifying the pathogenic mechanisms of SEZ., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Streptococcus equi ssp. zooepidemicus (SEZ) is a Gram-positive bacterium responsible for respiratory tract infection, septicemia, meningitis, endocarditis and arthritis in swine and humans. However, the expression and regulation of SEZ genes during an infection in vivo are poorly understood. In this study, we focused on the identification of SEZ genes preferentially expressed in vivo during infection in pigs. This study identified 45 SEZ genes that were upregulated in infected porcine lung tissues using the selective capture of transcribed sequences (SCOTS) technique and comparative dot-blot analysis, followed by quantitative RT-PCR validation. The identified genes were characterized into 6 functional categories: metabolism, cell wall-associated, stress response, transporters, regulators and unknown functions. Our study successfully identified multiple genes, which can deepen our understanding about SEZ pathogenesis and infer probable virulence factors. It will promote the development of novel vaccines and therapies about this pathogen for further study., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Two pyrogenic mitogens, SePE-H and SePE-I, were characterized in Streptococcus equi, the cause of equine strangles. SePE-H and SePE-I have molecular masses of 27.5 and 29.5 kDa, respectively, and each is almost identical to its counterpart in Streptococcus pyogenes M1. Both genes are adjacent to a gene encoding a phage muramidase of 49.7 kDa and are located immediately downstream from a phage genomic sequence almost identical to a similar phage sequence in S. pyogenes M1. Strong mitogenic responses were elicited by both proteins from horse peripheral blood mononuclear cells. However, although both were pyrogenic for rabbits, only SePE-I was pyrogenic in ponies. Convalescent sera contained antibody to each mitogen and horses recovered from strangles or immunized with SePE-I were resistant to the pyrogenic effect of SePE-I. The immunogenicity of SePE-I suggests that it should be included in new generation strangles vaccines. In isolates of S. equi sepe-I and sepe-H were consistently present but they were absent from the closely related Streptococcus zooepidemicus, suggesting that phage mediated transfer was an important event in the formation of the clonal, more virulent, S. equi from its putative S. zooepidemicus ancestor., (Copyright 2002 Academic Press.)

The capsule of Streptococcus equi, the cause of strangles, and Streptococcus zooepidemicus, associated with equine lower airway disease, plays an important role in evasion of phagocytosis by polymorphonuclear leucocytes. It is composed of hyaluronate, making it non-immunogenic. A hyaluronate associated protein (HAP) from S. equisimilis, whose gene has been sequenced [1], was investigated (a) for its presence in S. equi and S. zooepidemicus and (b) as an immunogen able to interfere with capsule structure and protect against experimental challenge of mice. The purified capsule of S. equi contained a protein of similar molecular mass to the S. equisimilis protein (approximately 53 kDa). Polymerase chain reaction (PCR) using primers derived from the published sequence of S. equisimilis HAP yielded a product from S. equi and S. zooepidemicus of the expected size and susceptibility to restriction endonucleases. Subcloning of two large in frame StuI/SspI fragments of the HAP gene from S. equi, approximately equivalent to the two halves of the molecule, into the expression vector pGEX-3X yielded only the carboxy half in the correct orientation. This latter recombinant produced a GST fusion protein (HAP-GST) of the expected size that was affinity purified. Antibodies in rabbit antiserum to the native protein in purified hyaluronate reacted strongly in immunoblots with HAP-GST. Antiserum to HAP-GST, when soaked into filter paper strips, caused a diminution of capsule production by S. equi cultured on blood agar. Antiserum added into fresh rabbit blood was not opsonic for S. equi. Immunization with HAP-GST significantly reduced rhinitis in Balb/C mice challenged nasally with S. equi and significantly increased survival time and clearance of bacteria in CBA/CA mice challenged intraperitoneally with S. zooepidemicus., (Copyright 1999 Academic Press.)