Streptococcus spp. are a genus of bacteria that can affect horses, leading to various infections and health conditions. These bacteria are known for causing respiratory and systemic diseases, including strangles, which is primarily caused by Streptococcus equi subsp. equi. Streptococcal infections in horses can result in symptoms such as fever, nasal discharge, and lymph node abscessation. The transmission typically occurs through direct contact with infected animals or contaminated environments. Diagnosis often involves bacterial culture or PCR testing. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, pathogenesis, diagnosis, and treatment of Streptococcus infections in equine populations.
Pereira Lopes A, Emanuel da Silva R, Sousa Santos L, de Morais Nobre ML, de Araujo Sousa PS, Almeida Rocha J, Veras Quelemes P, de Araujo-Nobre AR....The aim of this study was to investigate the antibacterial, antibiofilm and modulating activities of trans-trans-farnesol (tt-farnesol) on two strains of Streptococcus equi subsp. equi and two strains of S. equi subsp. zooepidemicus, pathogenic or commensal bacteria of horses. Tt-farnesol showed bactericidal activity against all tested strains, with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) between 8 and 4 μg/mL. The sesquiterpene caused significant damage to the bacterial membrane, and its antibacterial activity did not appear to depend on oxidat...
Junkkari R, Mykkänen A, Sulku P, Rantala M, Pohjanvirta T, Eklund M, Pelkonen S, Grönthal T. subsp. (), an opportunistic pathogen often found in the stable environment and upper respiratory tract of young horses, can cause severe pneumonias in Equidae. In this study we investigated the occurrence, genetic variation and antimicrobial susceptibility of isolates from 63 weanling horses kept in loose housing or conventional stables. The bacterial isolates were typed by using pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). The possible associating factors (stable type, age, breed and clinical signs) for positive finding were analysed using logistic regre...
Stolle LM, Oltmanns H, Meißner J, Heun F, Schieder AK, Wolff HT, Ohnesorge B, Busse C.To determine the in vitro antimicrobial activity of specific antiseptics against common equine ocular surface pathogens. Methods: Staphylococcus aureus (S. aureus) (n = 12), Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) (n = 9), Enterobacter hormaechei (E. hormaechei) (n = 6), and Bacillus cereus (B. cereus) (n = 5) were collected from corneal samples of horses with ulcerative keratitis. Reference strains were included. Minimum bactericidal concentrations (MBC) of polyhexanide, povidone-iodine, and hypochlorous acid were tested using the microdilution method. ...
Rask E, Righetti F, Ruiz A, Bjerketorp J, Frosth S, Frykberg L, Jacobsson K, Guss B, Flock JI, Henriques-Normark B, Hartman E, Gustafsson A....Infection of susceptible horses with subspecies (), the causative agent of strangles, is associated with commingling. Exposure may occur among horses at equestrian events, sales, or horses moved among different equine stabling environments. Strangles can affect all horses on a farm, leading to the death of up to 10% of cases depending on their immunity status at the time of infection, the development of complications, the success of biosecurity measures, and the use of vaccination. The current retrospective study used ELISAs to measure the exposure of horses to at a farm that experienced an...
He L, Khine NO, Song J, Loubière C, Butaye P.Strangles, caused by the host-adapted subsp. (. ), imposes significant welfare and economic losses on the equine industry worldwide. Understanding its genomic features, virulence-associated genes (VAGs), antimicrobial resistance (AMR) and mobile genetic elements (MGEs) is essential for disease control and vaccine development. This study aimed to characterize the accessory genome composition, geographic distribution of VAGs and MGEs, and AMR profiles of . by a large-scale genomic analysis of global publicly available . sequences. All publicly available . sequences in the Sequence Read Arch...
Da Silva-Álvarez E, Martín-Cano FE, Alonso JM, Becerro-Rey L, Zabalo-Palomo C, Gil MC, Peña FJ, Ortega-Ferrusola C.This study aims to characterize and compare the uterine fluid proteome and cytokine profile of reproductively healthy mares (HM; n = 15) and mares with Streptococcus equi subsp. zooepidemicus (S. zooepidemicus)-associated endometritis (SAE; n = 9). Uterine flush samples collected during the follicular phase were analyzed by shotgun proteomics and multiplex cytokine assays. Equine proteins were mapped to human orthologs, and enrichment and network analyses were performed using g:Profiler, Metascape, ToppGene, and STRING/MCODE. SAE mares showed higher levels of IL-1α, IL-1β, GRO, IL12p...
Gröndahl G, Righetti F, Aspán A, Bjerketorp J, Frosth S, Frykberg L, Jacobsson K, Guss B, Paillot R, Flock JI, Henriques-Normark B, Waller AS.Strangles, caused by Streptococcus equi subspecies equi (S. equi), is a prevalent infectious disease of horses. This is the first report on the use of a new vaccine, Strangvac, in a natural outbreak of strangles. Objective: To measure the effects of Strangvac vaccination during an outbreak of strangles at a Swedish farm. Methods: Longitudinal cohort study. Methods: Healthy horses (n = 17) were vaccinated on day 0, which occurred 23 days after strangles was first confirmed in three unvaccinated horses on the same farm. Blood serum samples were collected on day 0, day 28 and day 489. A com...
Barvelink M, Brok B, Djajadiningrat-Laanen SC, Vernooij JCM, Broens EM, Slenter IJM.To assess the antibacterial activity of manuka honey against bacterial isolates commonly associated with infected corneal ulcerations in horses, and to investigate possible combined effects of manuka honey and commonly prescribed topical antibiotics. Methods: Four Staphylococcus aureus, including three methicillin-resistant (MRSA), two methicillin-resistant coagulase-negative staphylococci (S. sciuri and S. haemolyticus), and two Streptococcus equi subspecies zooepidemicus isolates from horses with stromal ulcerative keratitis were selected. Minimum inhibitory concentrations (MICs) and minimu...
Righetti F, Hentrich K, Flock M, Frosth S, Jacobsson K, Bjerketorp J, Pathak A, Ido N, Henriques-Normark B, Frykberg L, Paillot R, Guss B, Wood T.... subspecies () is the cause of strangles, one of the most prevalent diseases of horses worldwide. The disease is characterised by fever and the formation of abscesses in the lymph nodes of the head and neck, which can restrict the airway. A multicomponent subunit vaccine, Strangvac, has been shown to effectively reduce clinical signs of strangles and to reduce its incidence. The aim of this study was to determine the immune response against the immunoglobulin-cleaving endopeptidase IdeE, a key protective component within the vaccine and the ability of antibodies to neutralize the proteolytic...
Pınar O, Çelik Doğan C, Aktaran Bala D, Kumaş C, Mete A.Riding clubs face significant financial losses due to upper respiratory infections caused by Beta-hemolytic (β-hemolytic) streptococci, leading to strangles and related diseases that negatively impact the health and performance of horses. Our objective was to determine the relationship between these inflammatory cells, the presence of β-hemolytic streptococcal species, and the clinical symptoms exhibited by the horses. This study investigated the presence of β-hemolytic streptococcus in 133 tracheal lavage samples from horses exhibiting various clinical respiratory symptoms and quantified t...
McLinden LA, Kemp-Symonds JG, Daly JM, Blanchard AM, Waller AS, Freeman SL.Infection with Streptococcus equi subspecies equi (S. equi) is characterised by acute disease, with about 10% of infected animals remaining persistently infected. Clinically, infection with S. equi cannot readily be distinguished from infection caused by other respiratory pathogens, including Streptococcus equi subspecies zooepidemicus (S. zooepidemicus), equine influenza virus, and equine herpes virus. Screening protocols, with appropriate quarantining facilities, are important to detect horses infected with S. equi and avoid strangles outbreaks. Virulent strains of S. zooepidemicus can also ...
Seeger MG, de Vargas APC, Vogel FSF, Cargnelutti JF.Streptococcus equi subsp. equi (S. equi) is the etiological agent of strangles, a contagious equine disease characterized by lymph node abscess and respiratory complications. To clarify the epidemiology and virulence factors of isolates, this study demonstrated phenotypic and genotypic differences between S. equi obtained from nasal secretions and lymph node aspirates of clinical strangles cases. Additionally, circulating alleles were differentiated through sequencing of the 5' end of the seM gene. A total of 23 clinical isolates collected from horses with strangles over the past decade were a...
subsp. (SEZ) is a bacterium that primarily affects horses but can also infect other animals and humans. In 2021-2022, two SEZ outbreaks occurred in Abruzzo, Italy: one in humans linked to unpasteurized cheese (37 cases) and another in donkeys (4 deaths). These events led researchers to investigate SEZ in horses, donkeys, and a mule in the regions of Abruzzo and Molise, focusing on antibiotic resistance and genetic traits. A total of 490 nasal and genital swabs were collected from equids and analyzed for SEZ presence, with 61 positive samples. Isolated strains underwent antimicrobial suscepti...
Roy CN, Wiechmann CE, Dev A, Walther BK, Musser JM, Olsen RJ, Beres SB, Axell-House DB. subsp. (SESZ) are zoonotic group C streptococci primarily acquired from contact with horses and other animals, such as llamas. They are unusual causes of infection in humans and rarely cause infective endocarditis. Unassigned: A 58-year-old woman presented with fever, malaise, and polyarthritis. Clinical evaluation diagnosed native tricuspid valve SESZ endocarditis. The SESZ isolate was genetically closely related to a clone causing an outbreak of post-streptococcal glomerulonephritis linked to the consumption of unpasteurized cheese in Brazil. The patient had no exposure to unpasteurized ch...
Iduu NV, Raiford D, Cohen ND, Landrock KK, Wang C.We developed a fluorescence resonance energy transfer (FRET)-based real-time PCR (qPCR) assay coupled with high-resolution melting (HRM) analysis to differentiate subsp. (SEE) from subsp. (SEZ), two closely related equine pathogens with distinct clinical implications. The assay targets a region of the 23S rRNA gene containing single-nucleotide polymorphisms that differentiate the subspecies. By combining subspecies-specific probes with melting temperature () analysis, the assay accurately distinguished SEE, SEZ, and mixed infections without the need for post-PCR processing. The entire work...
McGlennon AA, Verheyen KL, Newton JR, van Tonder A, Wilson H, Parkhill J, de Brauwere N, Frosth S, Waller AS.Strangles (Streptococcus equi infection) remains endemic in the UK, with ~300 laboratory diagnoses annually. Sub-clinically infected long-term carriers are considered a key driver of endemicity. Analysing genomes of circulating strains could provide valuable transmission insights of this pathogen. Objective: To determine the population structure and diversity of UK S. equi isolates and to model transmission using epidemiological and whole genome sequencing data. Methods: Retrospective cross-sectional epidemiological and genomic surveillance. Methods: A dated phylogenetic tree derived from 511...
Mohamed E, Van Cleemput J, Şahin B, Van den Broeck W, Boyen F, Nauwynck H.The equine respiratory and reproductive tract microbiomes are complex and subject to constant fluctuations. Among the microbial inhabitants, subsp. (SEZ) is recognized as the dominant bacterium. It is an opportunistic pathogen that may occasionally lead to various types of infections. A key virulence factor of SEZ is the streptolysin S (SLS) toxin, which is responsible for the characteristic β-hemolysis on blood agar and tissue damage. Viruses and bacteria may interact and aggravate lesions and disease. This study aimed to evaluate the impact of an SLS-containing supernatant from SEZ on the...
Tian Y, Su Y, Jiang X, Su L, Zhang B, Lv F.The zoonotic pathogen subspecies (SEZ) frequently colonizes equines harmlessly but can occasionally cause disease or cross species barriers. Currently, growing evidence suggests SEZ can lead to severe clinical manifestations in horses and other animals, posing a threat to human and companion animal health. In this study, we sequenced the complete genome of the SEZ strain HT321, a novel sequence type 420 isolated from a donkey with a respiratory infection in China. Subsequently, we conducted comparative genomics, core genome single nucleotide polymorphisms (cgSNP), phylogenetic analysis multi...
Żychska M, Rzewuska M, Kizerwetter-Świda M, Chrobak-Chmiel D, Stefańska I, Kwiecień E, Witkowski L.The rise of antibiotic resistance is a global health crisis affecting human and veterinary medicine, highlighted within the One Health framework. Horses, classified as both meat and companion animals, play a crucial role in facilitating resistant bacteria spread to humans. Despite increased awareness and reduced antibiotic use in livestock, data on equine antibiotic use and resistance remain limited. This retrospective study examines antimicrobial resistance in 978 bacterial isolates from horses in Poland over 12 years (2010-2022), utilizing data from the Microbiological Diagnostic Laboratory ...
Mikaiel T, Waller A, Foote A, Cardwell JM, Mitchell J, Priestnall SL.Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) is a commensal opportunistic bacterium associated with outbreaks of equine respiratory disease alongside a diverse range of diseases in various species. The closely related Streptococcus equi subspecies equi (S. equi) is the causative agent of 'strangles', the most frequently diagnosed contagious equine disease. Despite differing clinical signs, the two subspecies share approximately 97 % DNA homology and respectively present serious equine health and welfare concerns. Currently there are few PCR assays targeting unique regions of...
Christofi E, Hoopes J, El-Hage C, Coffin J, Riley T, Cumming B.Since their arrival in the 1700s, horses have played a significant role in shaping the identity of rural and remote communities. However, Indigenous perspectives on the historical role of horses in communities have been largely underrepresented. In remote regions, where access to veterinary and medical services is limited, interactions between people and free-roaming horses present a potential risk for zoonotic disease transmission. This review identifies potential pathways for the transmission of equine zoonoses in rural and remote Aboriginal and Torres Strait Islander communities, aiming to ...
Forni G, Ellero N, Mannini A, Scacco L, Freccero F.A 3-year-old Quarter Horse stallion was referred for headshaking (HS) syndrome of one month duration. The horse underwent complete HS workup. Physical examination revealed up-and-down head movements associated with nose snorting during lunging and riding, in the absence of other abnormalities at rest or in motion. Lameness, neurologic and behavioural evaluations were unremarkable. Endoscopic examination of the upper respiratory tract showed bilateral guttural pouches (GPs) inflammation. The mucosal surface was altered by the presence of areas of microbullous appearance coalescing into some bul...
Cito F, Di Francesco CE, Averaimo D, Chiaverini A, Alessiani A, Di Domenico M, Cresci M, Rulli M, Cantelmi MC, Di Bernardo MD, Giammarino A.... subsp. (SEZ) is a major problem in equine veterinary medicine. Typically, a commensal in horses, SEZ can cause severe disease including respiratory infections, septicaemia and reproductive tract infections under certain conditions. Recent evidence suggests that humans can also develop severe disease infection through direct contact with infected animals or the consumption of contaminated unpasteurised milk and milk products. This study investigates SEZ strains isolated from nasal swabs of equidae in central Italy in 2023 to describe the epidemiology and genomic characteristics of circulating...
Wilson HJ, Dong J, van Tonder AJ, Ruis C, Lefrancq N, McGlennon A, Bustos C, Frosth S, Léon A, Blanchard AM, Holden M, Waller AS, Parkhill J. subsp. causes the equine respiratory disease 'strangles', which is highly contagious, debilitating and costly to the equine industry. emerged from the ancestral subsp. and continues to evolve and disseminate globally. Previous work has shown that there was a global population replacement around the beginning of the twentieth century, obscuring the early genetic events in this emergence. Here, we have used large-scale genomic analysis of and its ancestor to identify evolutionary events, leading to the successful expansion of . One thousand two hundred one whole-genome sequences of were ...
Abdul-Latif SAK, Yousif AA.Strangles is a highly contagious equine respiratory disease caused by . It is a globally significant pathogen and one of the most common infectious agents in horses. In Iraq, no sequencing data on this pathogen are available, and only two molecular studies have been published to date. This study provides preliminary insights into strain diversity and provides a foundation for future large-scale investigations. Unassigned: This study aimed to investigate the molecular characteristics, identify gene alleles, and perform a phylogenetic analysis of isolates from horses in Baghdad, Iraq. Unassign...
Durward-Akhurst SA, Valberg SJ.Several inflammatory myopathies have an infectious or immune-mediated basis in the horse. Myosin heavy chain myopathy is caused by a codominant missense variant in MYH1 and has 3 clinical presentations: immune-mediated myositis, calciphylaxis, and nonexertional rhabdomyolysis in Quarter Horse-related breeds. An infarctive form of purpura hemorrhagica affects numerous breeds, presenting with focal firm, painful muscle swelling, and subsequent infarction of multiple tissues. While Streptococcus equi equi is often the inciting cause, anaplasmosis, sarcocystis, piroplasmosis, viruses, and vaccines...
Albert E, Biksi I, Laczkó L, Miló L, Cseri K, Bőkényné Tóth R, Papp D, Halmay D, Bódai E, Bakos Z.Here we report the isolation of Streptococcus hillyeri from a thoracic sample from a horse. A 17-y-old Hungarian Sport Horse mare was referred to the equine clinic of the University of Veterinary Medicine Budapest, Hungary, with suspected pleuritis. Upon arrival, the horse was febrile and had tachycardia, severe inspiratory dyspnea, and tachypnea. Thoracic ultrasonography revealed severe bilateral pleural effusion, and a large area of lung consolidation. After sampling of both hemithoraces, 66 L of turbid exudate were drained. Based on these findings, a tentative diagnosis of septic pleuritis ...
Carvalho Serena G, Marchezan Piva M, Viezzer Bianchi M, Fernandes da Fonseca HC, Chitolina Pupin R, Martins Basso R, Secorun Borges A....In horses, systemic calcinosis is a rare syndrome characterised by muscle lesion associated with the mineralisation of large muscle groups or other organs, in the absence of an alternative cause for the calcification, such as toxic, enzootic or metabolic. Molecular and histopathological aspects of the disease are still poorly elucidated. Objective: To describe the epidemiological, pathological and molecular aspects of systemic calcinosis in a convenience sample of six horses submitted to necropsy in the Southern and Midwestern regions of Brazil. Methods: Retrospective exploratory study. Method...
Styková E, Valocký I, Kačírová J, Fecskeová LK.Equine pastern dermatitis (EPD) is a multifactorial disease with a change in the skin microbiome. The present study monitored the influence of Weissella cibaria Biocenol™ 4/8 D37 CCM 9015 stabilized on alginite on the skin microbiota of healthy horses and model patients with EPD. Based on clinical signs, EPD lesions were identified as exudative or proliferative forms. A comparison of the initial microbial community based on 16S rRNA amplicon sequencing revealed that there was a statistically significant difference between healthy vs. exudative (R = 0.52, p = 0.003) and exudative vs. ...
Cohen ND, Hughes EV, Bayne C, Morris ERA, Bray JM, Landrock KK, Gonzales DM, Baker RM, Klein RL, Liu W, Legere RM, Wehmeyer SG, Bordin AI....Evaluate the immunogenicity of a vaccine targeting the S protein (Ssee) of Streptococcus equi subsp equi and determine antibody activity against Ssee in horses with strangles. Methods: The study was designed as a prospective experiment using 20 university-owned Quarter Horses and a cross-sectional serosurvey of 78 privately owned horses with strangles. Horses were immunized IM with 0 (n = 4), 200 (n = 8), or 400 (n = 8) μg of recombinant Ssee at weeks 0, 4, and 12. Serum and nasal secretions were collected at weeks 0, 4, 6, 12, 16, and 28 and tested by ELISA for immunoglobulin (Ig)-G against ...
Costa MC, Silva G, Ramos RV, Staempfli HR, Arroyo LG, Kim P, Weese JS.The advance of new sequencing technologies has allowed more comprehensive characterization of complex microbial communities, including the ones inhabiting the intestinal tract. The presence of extreme environmental filters, such as low pH, digestive enzymes and anaerobic conditions along the tract, acts on the selection of unique bacteria in each compartment. The intestinal microbiota has an enormous impact on the maintenance of health. However, data about the bacteria present in the different intestinal compartments of horses are sparse. In this study, high throughput sequencing was used to c...
Timoney JF.Streptococci pathogenic for the horse include S. equi (S. equi subsp. equi), S. zooepidemicus (S. equi subsp. zooepidemicus), S. dysgalactiae subsp. equisimilis and S. pneumoniae capsule Type III. S. equi is a clonal descendent or biovar of an ancestral S. zooepidemicus strain with which it shares greater than 98% DNA homology and therefore expresses many of the same proteins and virulence factors. Rapid progress has been made in identification of virulence factors and proteins uniquely expressed by S. equi. Most of these are expressed either on the bacterial surface or are secreted. Notable e...
LeBlanc MM, Causey RC.Endometritis, a major cause of mare infertility arising from failure to remove bacteria, spermatozoa and inflammatory exudate post-breeding, is often undiagnosed. Defects in genital anatomy, myometrial contractions, lymphatic drainage, mucociliary clearance, cervical function, plus vascular degeneration and inflamm-ageing underlie susceptibility to endometritis. Diagnosis is made through detecting uterine fluid, vaginitis, vaginal discharge, short inter-oestrous intervals, inflammatory uterine cytology and positive uterine culture. However, these signs may be absent in subclinical cases. Hyper...
Boyle AG, Timoney JF, Newton JR, Hines MT, Waller AS, Buchanan BR.This consensus statement update reflects our current published knowledge and opinion about clinical signs, pathogenesis, epidemiology, treatment, complications, and control of strangles. This updated statement emphasizes varying presentations in the context of existing underlying immunity and carrier states of strangles in the transmission of disease. The statement redefines the "gold standard" for detection of possible infection and reviews the new technologies available in polymerase chain reaction diagnosis and serology and their use in outbreak control and prevention. We reiterate the impo...
Pelkonen S, Lindahl SB, Suomala P, Karhukorpi J, Vuorinen S, Koivula I, Väisänen T, Pentikäinen J, Autio T, Tuuminen T.Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) is a zoonotic pathogen for persons in contact with horses. In horses, S. zooepidemicus is an opportunistic pathogen, but human infections associated with S. zooepidemicus are often severe. Within 6 months in 2011, 3 unrelated cases of severe, disseminated S. zooepidemicus infection occurred in men working with horses in eastern Finland. To clarify the pathogen's epidemiology, we describe the clinical features of the infection in 3 patients and compare the S. zooepidemicus isolates from the human cases with S. zooepidemicus isolates...
Webb K, Jolley KA, Mitchell Z, Robinson C, Newton JR, Maiden MCJ, Waller A.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 developme...
Riddle WT, LeBlanc MM, Stromberg AJ.Endometrial cytology and culture specimens (n=2123) were collected concurrently with a guarded uterine culture instrument from 970 mares (738 barren, 1230 foaling and 155 maiden mares) during three breeding seasons (2001-2004). Results were compared to the 28-d pregnancy rate for the cycle from which the samples were taken. Cytological smears were evaluated for inflammation at x100 and graded as: not inflammatory (0-2 neutrophils/field), moderate inflammation (2-5 neutrophils/field), severe inflammation (>5 neutrophils/field), or hypocellular (scant epithelial cells and no neutrophils). Ute...
Wood JL, Newton JR, Chanter N, Mumford JA.Respiratory disease is important in horses, particularly in young Thoroughbred racehorses, and inflammation that is detected in the trachea and bronchi (termed inflammatory airway disease [IAD]) is more significant in this population in terms of impact and frequency than other presentations of respiratory disease. IAD, which is characterized by neutrophilic inflammation, mild clinical signs, and accumulation of mucus in the trachea, may be multifactorial, possibly involving infections and environmental and immunological factors, and its etiology remains unclear. This 3-year longitudinal study ...
Milinovich GJ, Burrell PC, Pollitt CC, Klieve AV, Blackall LL, Ouwerkerk D, Woodland E, Trott DJ.Alimentary carbohydrate overload is a significant cause of laminitis in horses and is correlated with drastic shifts in the composition of hindgut microbiota. Equine hindgut streptococcal species (EHSS), predominantly Streptococcus lutetiensis, have been shown to be the most common microorganisms culturable from the equine caecum prior to the onset of laminitis. However, the inherent biases of culture-based methods are estimated to preclude up to 70% of the normal caecal microbiota. The objective of this study was to evaluate bacterial population shifts occurring in the equine caecum throughou...
Bond SL, Timsit E, Workentine M, Alexander T, Léguillette R.The microbial composition of the equine respiratory tract, and differences due to mild equine asthma (also called Inflammatory Airway Disease (IAD)) have not been reported. The primary treatment for control of IAD in horses are corticosteroids. The objectives were to characterize the upper and lower respiratory tract microbiota associated with respiratory health and IAD, and to investigate the effects of dexamethasone on these bacterial communities using high throughput sequencing. Results: The respiratory microbiota of horses was dominated by four major phyla, Proteobacteria (43.85%), Actinob...
Båverud V, Johansson SK, Aspan A.Strangles is a contagious equine disease caused by Streptococcus equi subsp. equi. In this study, clinical strains of S. equi (n=24) and Streptococcus equi subsp. zooepidemicus (n=24) were genetically characterized by sequencing of the 16S rRNA and sodA genes in order to devise a real-time PCR system that can detect S. equi and S. zooepidemicus and distinguish between them. Sequencing demonstrated that all S. equi strains had the same 16S rRNA sequence, whereas S. zooepidemicus strains could be divided into subgroups. One of these (n=12 strains) had 16S rRNA sequences almost identical with the...
Kelly C, Bugg M, Robinson C, Mitchell Z, Davis-Poynter N, Newton JR, Jolley KA, Maiden MC, Waller AS.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...
Harris SR, Robinson C, Steward KF, Webb KS, Paillot R, Parkhill J, Holden MT, Waller AS.Strangles, the most frequently diagnosed infectious disease of horses worldwide, is caused by Streptococcus equi. Despite its prevalence, the global diversity and mechanisms underlying the evolution of S. equi as a host-restricted pathogen remain poorly understood. Here, we define the global population structure of this important pathogen and reveal a population replacement in the late 19th or early 20th Century. Our data reveal a dynamic genome that continues to mutate and decay, but also to amplify and acquire genes despite the organism having lost its natural competence and become host-rest...
Turner CE, Kurupati P, Wiles S, Edwards RJ, Sriskandan S.Currently there is no licensed vaccine against the human pathogen Streptococcus pyogenes. The highly conserved IL-8 cleaving S. pyogenes cell envelope proteinase SpyCEP is surface expressed and is a potential vaccine candidate. A recombinant N-terminal part of SpyCEP (CEP) was expressed and purified. AntiCEP antibodies were found to neutralize the IL-8 cleaving activity of SpyCEP. CEP-immunized mice had reduced bacterial dissemination from focal S. pyogenes intramuscular infection and intranasal infection. We also identified a functional SpyCEP-homolog protease SeCEP, expressed by the equine p...
Milinovich GJ, Trott DJ, Burrell PC, van Eps AW, Thoefner MB, Blackall LL, Al Jassim RA, Morton JM, Pollitt CC.In the horse, carbohydrate overload is thought to play an integral role in the onset of laminitis by drastically altering the profile of bacterial populations in the hindgut. The objectives of this study were to develop and validate microbial ecology methods to monitor changes in bacterial populations throughout the course of experimentally induced laminitis and to identify the predominant oligofructose-utilizing organisms. Laminitis was induced in five horses by administration of oligofructose. Faecal specimens were collected at 8 h intervals from 72 h before to 72 h after the administration ...
Newton JR, Wood JL, Dunn KA, DeBrauwere MN, Chanter N.During an outbreak of strangles on a farm with approximately 1500 horses, the spread of Streptococcus equi infection was monitored by repeated nasopharyngeal swabbing and culture. In order to control the infection and prevent new introductions of strangles on to the premises, a system of quarantine and swabbing of cases and all incoming animals was instituted. Long-term carriage of the organism was detected in four clinically healthy convalescent animals, and in two of 350 new ponies; it persisted for between seven and 39 months, but it was detected only intermittently by the culture of swabs ...
Burrell MH, Wood JL, Whitwell KE, Chanter N, Mackintosh ME, Mumford JA.A longitudinal study of respiratory disease in racehorses was carried out to assess its relative associations with different infectious agents and to examine any role that the environmental conditions might play. The relationships between coughing, nasal discharge, pyrexia and lower respiratory tract disease were also examined to provide information for improving clinical diagnosis, particularly of disease of the lower respiratory tract. Lower airway disease was closely associated with infection with Streptococcus zooepidemicus. It was also found that equine herpesvirus seroconversions and S p...
Hoopes JT, Stark CJ, Kim HA, Sussman DJ, Donovan DM, Nelson DC.Streptococcus equi is the causative agent of the purulent infection equine strangles. This disease is transmitted through shedding of live bacteria from nasal secretions and abscess drainage or by contact with surfaces contaminated by the bacteria. Disinfectants are effective against S. equi, but inactivation by environmental factors, damage to equipment, and toxicity are of great concern. Bacteriophage-encoded lysins (cell wall hydrolases) have been investigated as therapeutic agents due to their ability to lyse susceptible gram-positive organisms. Here, we investigate the use of one lysin, P...
Frontoso R, De Carlo E, Pasolini MP, van der Meulen K, Pagnini U, Iovane G, De Martino L.Bacterial pathogens are a potential cause when a mare fails to conceive to a fertile stallion on a well-managed breeding farm on one or more cycles in the same season. Furthermore, emerging bacterial resistance to commonly used (topical) antibiotics has been demonstrated. In this study, a total of 586 uterine swabs from mares with fertility problems were evaluated and the bacterial isolates were identified and measured for resistance to 10 antibiotics most commonly used during bacterial equine infection. Forty-nine percent of the examined mares were positive at bacteriological investigations. ...
Lannergård J, Guss B.Streptococcus equi ssp. equi is the causative agent of strangles, a highly contagious and serious disease in the upper respiratory tract of horses. The present study describes the characterization of IdeE, a homolog of the secreted IgG-specific protease IdeS/Mac of Streptococcus pyogenes. The activity of IdeE is compared with the activity of IdeZ, the corresponding enzyme of the closely related S. equi ssp. zooepidemicus. A study of the proteolytic activity of recombinant IdeE and IdeZ on IgG from a selection of mammals shows that only antibodies containing the substrate site of IdeS/Mac are c...
Harrington DJ, Sutcliffe IC, Chanter N.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.
Newton JR, Verheyen K, Talbot NC, Timoney JF, Wood JL, Lakhani KH, Chanter N.Previous use of repeated nasopharyngeal swabbing and culture of Streptococcus equi showed that healthy carriers developed in more than 50% of 'strangles' outbreaks. The guttural pouches were the only detectable site of S. equi colonisation on endoscopic examination of horses during one of these outbreaks and S. equi was sometimes not detected by culture of nasopharyngeal swabs from carriers for up to 2 or 3 months before nasal shedding resumed sporadically. A more sensitive way of detecting S. equi on swabs from established guttural pouch carriers was therefore required. Conveniently selected ...
Erol E, Locke SJ, Donahoe JK, Mackin MA, Carter CN.The goal of this retrospective study was to have a comprehensive picture of the β-hemolytic streptococci of horses including tissue/organ distributions and susceptibility patterns against specific antimicrobials between January 1, 2000 and December 31, 2010. A total of 2,497 β-hemolytic streptococci were isolated from 2,391 cases, of which Streptococcus equi subsp. zooepidemicus was the most frequent isolate (72.0%). Other species isolated were Streptococcus dysgalactia subsp. equisimilis (21.3%), Streptococcus equi subsp. equi (5.8%), and unidentified β-hemolytic streptococci (0.9%). As ex...
Hamilton A, Robinson C, Sutcliffe IC, Slater J, Maskell DJ, Davis-Poynter N, Smith K, Waller A, Harrington DJ.Streptococcus equi is the causative agent of strangles, a prevalent and highly contagious disease of horses. Despite the animal suffering and economic burden associated with strangles, little is known about the molecular basis of S. equi virulence. Here we have investigated the contributions of a specific lipoprotein and the general lipoprotein processing pathway to the abilities of S. equi to colonize equine epithelial tissues in vitro and to cause disease in both a mouse model and the natural host in vivo. Colonization of air interface organ cultures after they were inoculated with a mutant ...
Lüthje P, Schwarz S.In this study, erythromycin- and/or clindamycin-resistant isolates among 248 coagulase-positive and coagulase-variable staphylococci and 500 streptococci, collected all over Germany during 2004-2006 in the resistance monitoring program BfT-GermVet, were investigated for their genetic basis of macrolide and/or lincosamide resistance. Staphylococci were sampled from various disease conditions of dogs/cats or pigs, whereas streptococci were from dogs/cats, pigs or horses. Resistant staphylococci were further identified biochemically to species and subspecies level and tested for the resistance ge...
Minces LR, Brown PJ, Veldkamp PJ.Streptococcus equi subsp. zooepidemicus rarely causes meningitis in humans by contact with domestic animals or their unpasteurized products. In this paper we reviewed the literature pertaining to the epidemiological and clinical aspects relating to this infection on previously reported cases of human disease. Additionally, the case of a 51-year-old female who acquired meningitis with this organism after contact with a horse is described. This patient was successfully treated with ceftriaxone, yet penicillin remains the treatment of choice. This aetiological agent should be considered in the pr...
Rebordão MR, Carneiro C, Alexandre-Pires G, Brito P, Pereira C, Nunes T, Galvão A, Leitão A, Vilela C, Ferreira-Dias G.Besides the classical functions, neutrophils (PMNs) are able to release DNA in response to infectious stimuli, forming neutrophil extracellular traps (NETs) and killing pathogens. The pathogenesis of endometritis in the mare is not completely understood. The aim was to evaluate the in vitro capacity of equine PMNs to secrete NETs by chemical activation, or stimulated with Streptococcus equi subspecies zooepidemicus (Szoo), Escherichia coli (Ecoli) or Staphylococcus capitis (Scap) strains obtained from mares with endometritis. Ex vivo endometrial mucus from mares with bacterial endometritis wer...
Lannergård J, Frykberg L, Guss B.Streptococcus equi subspecies equi is an important horse pathogenic bacterium causing a serious disease called strangles. Using bioinformatics we identified a gene denoted cne (gene encoding collagen-binding protein from S. equi) coding for a novel potential virulence factor of this species called protein CNE. The protein is composed of 657 amino acids and has the typical features found in cell surface-anchored proteins in Gram-positive bacteria. CNE displays amino acid sequence similarities to the previously well-studied collagen-binding protein CNA from Staphylococcus aureus, a proven virule...
Johns IC, Adams EL.This study aimed to identify changing antimicrobial resistance patterns in isolates commonly obtained from equine clinical submissions. Laboratory records from 1999 to 2012 were searched for equine samples from which Escherichia coli or Streptococcus species was isolated. Susceptibility to enrofloxacin, ceftiofur, gentamicin, penicillin G, trimethoprim sulfamethoxazole (TMPS) and tetracyclines was noted. Isolates were divided into those identified between 1999 and 2004 (Early) and between 2007 and 2012 (Late). The proportion of isolates resistant to each antimicrobial and multiple drug-resista...
