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.
Durward-Akhurst SA, Valberg SJ.In horses, immune-mediated muscle disorders can arise from an overzealous immune response to concurrent infections or potentially from an inherent immune response to host muscle antigens. Streptococcus equi ss. equi infection or vaccination can result in infarctive purpura hemorrhagica (IPH) in which vascular deposition of IgA-streptococcal M protein complexes produces ischemia and complete focal infarction of skeletal muscle and internal organs. In Quarter Horse-related breeds with immune-mediated myositis, an apparent abnormal immune response to muscle antigens results in upregulation of maj...
Harvey A, Kilcoyne I, Byrne BA, Nieto J.To compare synovial concentrations of amikacin following intravenous regional limb perfusion (IVRLP) with two different doses, and to compare their ability to reach target concentrations for bacterial isolates from common orthopedic conditions. Methods: Randomized crossover experiment. Methods: Six adult horses. Methods: Horses received IVRLP with 2 and 3 g of amikacin in the cephalic vein of alternate limbs (20 minutes tourniquet application and ≥14 days washout period). Amikacin concentrations were quantified in synovial fluid collected from the middle carpal and metacarpophalangeal joints...
Javed R, Taku AK, Gangil R, Sharma RK.The aim was to determine the occurrence of streptococci in equines in Jammu (R. S. Pura, Katra), characterization of Streptococci equi subsp. equi and Streptococcus equi subsp. zooepidemicus with respect to their virulence traits and to determine antibiotic sensitivity pattern of virulent Streptococcus isolates. Methods: A total of 96 samples were collected from both clinically affected animals (exhibiting signs of respiratory tract disease) and apparently healthy animals and were sent to laboratory. The organisms were isolated on Columbia nalidixic acid agar containing 5% sheep blood as well ...
Pinho MD, Erol E, Ribeiro-Gonçalves B, Mendes CI, Carriço JA, Matos SC, Preziuso S, Luebke-Becker A, Wieler LH, Melo-Cristino J, Ramirez M.The pathogenic role of beta-hemolytic Streptococcus dysgalactiae in the equine host is increasingly recognized. A collection of 108 Lancefield group C (n = 96) or L (n = 12) horse isolates recovered in the United States and in three European countries presented multilocus sequence typing (MLST) alleles, sequence types and emm types (only 56% of the isolates could be emm typed) that were, with few exceptions, distinct from those previously found in human Streptococcus dysgalactiae subsp. equisimilis. Characterization of a subset of horse isolates by multilocus sequence analysis (MLSA) a...
Tirosh-Levy S, Blum SE, Steward KF, Waller AS, Steinman A.The purpose of this cross-sectional study was to determine the seroprevalence of Streptococcus equi in Israel, to monitor seropositive horses over time and to identify archived strains that were recovered from Israeli horses. A serological survey of 200 healthy horses on 20 farms throughout Israel was performed to detect recent exposure to S equi antigens A and C via indirect ELISA. Seroprevalence was 9.5 per cent (19/200) and positive horses were found in 30 per cent (6/20) of the farms. Sixteen horses that returned a positive serology result were retested three and six months later. Most (12...
Neamat-Allah AN, Damaty HM.Respiratory tract infections are considered the major problem of equine worldwide. Strangles is an infectious and highly contagious respiratory bacterial disease of equine caused by Streptococcus equi. This study is aimed to evaluate some clinical and epidemiological investigation associated with strangles and to study the hematological and biochemical changes in 20 Arabian horse naturally infected with S. equi during the disease and after 10 days from treatment by procaine penicillin with benzathine penicillin. Methods: A total of 490 Arabian horses have been examined, 120 (24.5%) have been c...
Kawakami V, Rietberg K, Lipton B, Eckmann K, Watkins M, Oltean H, Kay M, Rothschild C, Kobayashi M, Van Beneden C, Duchin J.On March 17, 2016, Public Health-Seattle & King County in Washington was notified of two persons who received a diagnosis of Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) infections. S. zooepidemicus is a zoonotic pathogen that rarely causes human illness and is usually associated with consuming unpasteurized dairy products or with direct horse contact (1). In horses, S. zooepidemicus is a commensal bacterium that can cause respiratory, wound, and uterine infections (2). The health department investigated to determine the magnitude of the outbreak, identify risk factors, and o...
Kendall A, Mayhew IG, Petrovski K.Treatment of subclinical carriers of Streptococcus equi subsp. equi with a gelatine-penicillin formulation deposited in the guttural pouch has been empirically proposed, but data on local tissue penicillin concentrations after treatment are lacking. Methods: We analysed tissue levels of penicillin after administration into the guttural pouches of four healthy horses. Two horses received local treatment with gelatine-penicillin and two horses received local treatment with an intramammary formulation of penicillin. Tissues were harvested for analysis either 12 or 24 h later. Conclusions: Resul...
Livengood JL, Lanka S, Maddox C, Tewari D.Streptococcus equi subspecies equi (S. equi), the causative agent of strangles, is an important equine pathogen. Strangles is a highly contagious disease and a commercial modified live vaccine (MLV) is used for protection, which although effective, may also result in clinical signs of the disease. A rapid means to differentiate between the MLV and wild-type infection is crucial for quarantine release and limiting the disease spread. This study describes the use of a pyrosequencing assay targeting a single nucleotide deletion upstream of the SzPSe gene to distinguish between the wild-type and v...
Waller AS.Strangles, characterised by pyrexia followed by abscessation of the lymph nodes of the head and neck, was first described in 1251 (Rufus 1251) and the causative agent, Streptococcus equi, was identified in 1888 (Schutz 1888). However, despite more than a century of research into this disease, strangles remains the most frequently diagnosed infection of horses with over 600 outbreaks being identified in the UK alone each year (Parkinson and others 2011). Here, Andrew Waller reviews some of the recent advances in the understanding of the evolution of S equi and puts this into the context of prev...
Boyle AG, Rankin SC, D￮ L, Boston RC, Wheeler-Aceto H.Bacterial culture and polymerase chain reaction (PCR) assays for the detection of Streptococcus equi in nasopharyngeal washes (NPW) and guttural pouch lavage (GPL) samples have low sensitivity. In human diagnostics, processing of samples with flocked swabs has improved recovery rates of bacterial agents because of improved surface area and elution factors. Objective: For S. equi subsp. equi (S. equi) detection in NPW and GPL samples we hypothesized that: direct-PCR would be more reliable than flocked swab culture (FS culture); flocked swab PCR (FS-PCR) would be equivalent to direct-PCR; and FS...
Toombs-Ruane LJ, Riley CB, Kendall AT, Hill KE, Benschop J, Rosanowski SM.To describe antimicrobial susceptibility, and identify antimicrobial resistance (AMR), in bacteria isolated from New Zealand foals. Methods: A database search was performed of submissions to a veterinary pathology laboratory between April 2004 and December 2013 for bacterial culture of samples from foals <3 weeks of age. Culture and susceptibility results were compiled with demographic information. Susceptibility results were as defined for the Kirby-Bauer disk diffusion susceptibility test based on Clinical Laboratory Standards Institute guidelines. Multi-drug resistance (MDR) was defined as ...
Libardoni F, Machado G, Gressler LT, Kowalski AP, Diehl GN, dos Santos LC, Corbellini LG, de Vargas AC.The aim of this study was to estimate the prevalence of equine strangles and to identify associated risk factors for this disease through a cross-sectional study of nasal swabs. Nasal swabs (n=1010) from healthy equines (absence of nasal discharge, lymphadenopathy and cough) from 341 farms were plated on 5% blood agar; of these horses, 24 were identified as positive for Streptococcus equi through isolation, PCR and DNA sequencing. The estimated prevalence for individual animals was 2.3%, and for herds, it was 5.86%. Statistical analysis identified the following as associated risk factors: the ...
D￮ LR, Stefanovski D, Boston RC, Boyle AG.To evaluate predictor variables for and complications associated with Streptococcus equi subsp equi infection (strangles) in horses. Methods: Retrospective case-control study. Methods: 108 horses with strangles (cases) and 215 horses without strangles (controls). Methods: Medical records from January 2005 through July 2012 were reviewed. Cases were defined as horses with clinical signs of strangles (pyrexia, retropharyngeal lymphadenopathy, and mucopurulent nasal discharge) that were associated with a confirmed strangles outbreak or had positive results for S equi on PCR assay or bacteriologic...
Harlow BE, Donley TM, Lawrence LM, Flythe MD.The goal was to determine the effect of starch source (corn, oats and wheat) and concentration on: (i) total amylolytic bacteria, Group D Gram-positive cocci (GPC), lactobacilli and lactate-utilizing bacteria, and (ii) fermentation by equine microbiota. Results: When faecal washed cell suspensions were incubated with any substrate amylolytics increased over time. However, at 24 h there were 10 and 1000-fold more amylolytics with corn than wheat or oats respectively. Predominant amylolytics isolated were Enterococcus faecalis (corn, wheat) and Streptococcus bovis (oats). GPC increased with any ...
Velineni S, DeNegri R, Artiushin SC, Timoney JF.Streptococcus zooepidemicus (Sz) and its clonal derivative Streptococcus equi (Se) share greater than 96% DNA identity and elicit immune responses to many shared proteins. Identification of proteins uniquely targeted by the immune response to each infection would have diagnostic value. Objective: The aim of the study was to compare serum antibody responses of horses infected by Se or Sz. Methods: Antibody levels were measured to panels of recombinant proteins of Sz and Se in sera of horses and ponies before and after experimental and naturally occurring invasive infections by these organisms. ...
Toombs-Ruane LJ, Riley CB, Kendall AT, Bolwell CF, Benschop J, Rosanowski SM.Decreased efficacy of antimicrobials and increased prevalence of multidrug resistance (MDR) is of concern worldwide. Objective: To describe and analyze bacterial culture and antimicrobial susceptibilities from respiratory samples submitted from young horses (4 weeks to 3 years old). Methods: Samples from 289 horses were submitted to a commercial laboratory. Methods: A retrospective database search of submissions made to a New Zealand veterinary laboratory between April 2004 and July 2014. The results of in vitro susceptibility testing by Kirby-Bauer disc diffusion were described and tabulat...
Cordoni G, Williams A, Durham A, Florio D, Zanoni RG, La Ragione RM.Strangles is one of the most common equine infectious diseases with serious health, welfare and socio-economic impact. However, the detection of Streptococcus equi subspecies equi can be challenging and persistently infected carriers are common. Furthermore, the use of classical microbiology can result in an underestimation of the prevalence of the disease. The difficulties associated with the slow diagnosis of Strangles can result in rapid spread of the disease. Therefore, rapid and economical diagnostic tests are urgently required. Here, two multiplex assays, were developed and validated for...
Christoffersen M, Söderlind M, Rí»ºlk SR, Pedersen HG, Allen J, Krekeler N.Infectious endometritis is a major cause of infertility in the mare and inflicts major losses on the equine breeding industry. The ability of the mare to eliminate uterine infections has been studied intensively for decades; however, despite identification of several factors contributing to the multifactorial pathogenesis and improved treatment, infectious endometritis remains a significant problem in a subpopulation of broodmares. Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) is one of the most commonly isolated pathogens from the uterus of mares, suffering from infectious endom...
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...
Acke E, Midwinter AC, Lawrence K, Gordon SJ, Moore S, Rasiah I, Steward K, French N, Waller A.To estimate the prevalence of β-haemolytic Lancefield group C streptococci in healthy dogs, cats and horses; to determine if frequent contact with horses was associated with isolation of these species from dogs and cats; and to characterise recovered S. equi subsp. zooepidemicus isolates by multilocus sequence typing. Methods: Oropharyngeal swabs were collected from 197 dogs and 72 cats, and nasopharyngeal swabs from 93 horses. Sampling was carried out at the Massey University Veterinary Teaching Hospital, on sheep and beef farms or on premises where horses were present. All animals were heal...
Petersen MR, Skive B, Christoffersen M, Lu K, Nielsen JM, Troedsson MH, Bojesen AM.Endometritis in horses caused by Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) may be underdiagnosed due to traditional diagnostic methods lacking sensitivity and specificity. We serendipitously identified a bacterial growth medium (bActivate) that appeared capable of inducing growth of dormant S. zooepidemicus, which subsequently allowed detection by standard diagnostics. To assess the effect of bActivate we compared its ability to activate dormant S. zooepidemicus in a group of potentially infected subfertile mares with phosphate-buffered saline (PBS). All mares had to test ...
McClure SR, Koenig R, Hawkins PA.To evaluate the effectiveness of a novel trimethoprim-sulfadiazine oral suspension for the treatment of naturally acquired Streptococcus equi subsp zooepidemicus infection in horses. Methods: Randomized, controlled field trial. Methods: 180 horses with S equi subsp zooepidemicus infection. Methods: Horses with lower respiratory tract infections caused by S equi subsp zooepidemicus were treated with a new formulation of combined trimethoprim-sulfadiazine oral suspension at a dosage of 24 mg/kg (10.9 mg/lb) twice daily for 10 days (treatment group) or with an equivalent volume of saline (0.9% Na...
Kudirkiene E, Welker M, Knudsen NR, Bojesen AM.Streptococcus equi includes very important animal and human pathogens. S. equi subsp. equi (SEE) is a highly pathogenic equine specific subspecies, while S. equi subsp. zooepidemicus (SEZ) and S. equi subsp. ruminatorum are opportunistic pathogens of various animal species and humans. Due to great phenotypic and sequence similarity between three subspecies their discrimination remains difficult. In this study, we aimed to design and validate a novel, Superspectra based, MALDI-TOF MS approach for reliable, rapid and cost-effective identification of SEE and SEZ, the most frequent S. equi subspec...
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...
Hidaka S, Kobayashi M, Ando K, Fujii Y.Lomefloxacin is a broad-spectrum fluoroquinolone antibiotic used for the treatment of bacterial extraocular disease. This study investigated the efficacy and safety of lomefloxacin eye drops for bacterial extraocular disease in horses. Lomefloxacin ophthalmic solution (0.3%) was instilled three times daily for 2-5 days in 65 horses diagnosed with bacterial extraocular disease based on clinical findings. Clinical observations and bacteriological examinations were performed at the start of treatment, 2 and 5 days after the start of treatment, and at the discontinuation or termination of treatmen...
Michalek M, Jung S, Shomali MR, Cauchard S, Sönnichsen FD, Grötzinger J.Defensins are small effector molecules of the innate immune system that are present in almost all organisms including plants and animals. These peptides possess antimicrobial activity against a broad range of microbes including bacteria, fungi and viruses and act as endogenous antibiotics. α-Defensins are a subfamily of the defensin family and their expression is limited to specific tissues. Equine DEFA1 is an enteric α-defensin exclusively secreted by Paneth cells and shows an activity against a broad spectrum of microbes, including typical pathogens of the horse such as Rhodococcus equi, v...
McLean R, Rash NL, Robinson C, Waller AS, Paillot R.Streptococcus equi subspecies equi (S. equi) is the causative agent of strangles, a highly contagious upper respiratory disease of equids. Streptococcus equi produces superantigens (sAgs), which are thought to contribute to strangles pathogenicity through non-specific T-cell activation and pro-inflammatory response. Streptococcus equi infection induces abscesses in the lymph nodes of the head and neck. In some individuals, some abscess material remains into the guttural pouch and inspissates over time to form chondroids which can harbour live S. equi. The aim of this study was to determine...
Silva LG, Genteluci GL, Corrêa de Mattos M, Glatthardt T, Sá Figueiredo AM, Ferreira-Carvalho BT.Streptococcus dysgalactiae subsp. equisimilis (SDSE) isolates are the most common group C streptococci in humans and reports of invasive infections associated with SDSE have been increasing. Molecular epidemiology studies are an important strategy to trace the emergence and spread of possible well-fit bacterial pathogens of humans and animals. In this work, we analysed the antimicrobial and clonal profiles of 115 SDSE infection and colonization isolates of human and equine origin. PFGE revealed the spread of two main clusters: clone A (57.4%) and clone A (26.1%). Remarkably, two isolates from ...
Steward KF, Harrison T, Robinson C, Slater J, Maskell DJ, Harris SR, Holden MTG, Waller AS.Opportunistic pathogens must adapt to and survive in a wide range of complex ecosystems. Streptococcus zooepidemicus is an opportunistic pathogen of horses and many other animals, including humans. The assembly of different surface architecture phenotypes from one genotype is likely to be crucial to the successful exploitation of such an opportunistic lifestyle. Construction of a series of mutants revealed that a serine recombinase, PinR, inverts 114 bp of the promoter of SZO_08560, which is bordered by GTAGACTTTA and TAAAGTCTAC inverted repeats. Inversion acts as a switch, controlling the tra...
Pusterla N, Watson JL, Affolter VK, Magdesian KG, Wilson WD, Carlson GP.The medical records of 53 horses with purpura haemorrhagica were reviewed. Seventeen of them had been exposed to or infected with Streptococcus equi, nine had been infected with Corynebacterium pseudotuberculosis, five had been vaccinated with S. equi M protein, five had had a respiratory infection of unknown aetiology, and two had open wounds; the other 15 cases had no history of recent viral or bacterial infection. The horses were between six months and 19 years of age (mean 8.4 years). The predominant clinical signs were well demarcated subcutaneous oedema of all four limbs and haemorrhages...
Harlow BE, Lawrence LM, Kagan IA, Flythe MD.The goals of this study were to determine if β-acid from hops (Humulus lupulus L.) could be used to control fructan fermentation by equine hindgut micro-organisms, and to verify the antimicrobial mode of action on Streptococcus bovis, which has been implicated in fructan fermentation, hindgut acidosis and pasture-associated laminitis (PAL) in the horse. Results: Suspensions of uncultivated equine faecal micro-organisms produced fermentation acids when inulin (model fructan) was the substrate, but β-acid (i.e. lupulone) concentrations ≥9 ppm inhibited lactate production and mitigated the d...
Rotinsulu DA, Ewers C, Kerner K, Amrozi A, Soejoedono RD, Semmler T, Bauerfeind R.Strangles, caused by ssp. (), is a highly infectious and frequent disease of equines worldwide. No data are available regarding the molecular epidemiology of strangles in Indonesia. This study aimed to characterize isolates obtained from suspected strangles cases in Indonesia in 2018. Isolates originated from seven diseased horses on four different farms located in three provinces of Indonesia. Whole genome sequences of these isolates were determined and used for typing, multilocus sequence typing (MLST), and core genome MLS typing (cgMLST). Genomes were also screened for known antimicrobi...
Muranaka M, Yamanaka T, Katayama Y, Niwa H, Oku K, Matsumura T, Oyamada T.To investigate the pathology of equine influenza, necropsy of 7 horses experimentally infected with equine influenza A virus (EIV) subtype H3N8 was conducted on post-infection days (PID) 2, 3, 7, and 14. Histopathologically, rhinitis or tracheitis including epithelial degeneration or necrosis with loss of ciliated epithelia and a reduction in goblet cell numbers, was observed in the respiratory tracts on PIDs 2 and 3. Epithelial hyperplasia or squamous metaplasia and suppurative bronchopneumonia with proliferation of type II pneumocytes were observed on PIDs 7 and 14. Viral antigen was detecte...
Waller AS, Jolley KA.'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/s...
Hamlen HJ, Timoney JF, Bell RJ.A 2-phase study was performed to characterize the effects of Streptococcus equi infection in unexposed and previously exposed foals. In phase I, 22 weanling foals involved in a naturally occurring S equi epizootic were studied, along with a comparison group of 11 unexposed foals, matched for age, sex, and breed. Six months later (phase II), an epizootic was experimentally induced in previously exposed and unexposed foals from phase I. The prevalence and duration of clinical signs, the relative risk of developing disease, bacteriologic culture results, hematologic responses, and mucosal and ser...
Nagy AD, Simhofer H.To report use of mandibular condylectomy for treatment of advanced degenerative joint disease of the temporomandibular joint (TMJ) caused by sepsis. Methods: Clinical case report. Methods: Two-year-old Noriker filly. Methods: Computed tomography (CT) was used to confirm advanced degenerative joint disease of the left TMJ and for follow-up after mandibular condylectomy and removal of necrotic meniscus. Results: Painful swelling (3 weeks duration) with drainage located just caudal to the left lateral canthus of the eye was associated with atrophy of the left masseter muscle, masticatory problems...
Mani RJ, Thachil AJ, Ramachandran A.Accurate and timely identification of infectious etiologies is of great significance in veterinary microbiology, especially for critical diseases such as strangles, a highly contagious disease of horses caused by Streptococcus equi subsp. equi. We evaluated a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) platform for use in species- and subspecies-level identification of S. equi isolates from horses and compared it with an automated biochemical system. We used 25 clinical isolates each of S. equi subsp. equi and S. equi subsp. zooepidemicus. Using ...
Timoney JF, Suther P, Velineni S, Artiushin SC.Resistance to phagocytosis is a crucial virulence property of Streptococcus equi (Streptococcus equi subsp. equi; Se), the cause of equine strangles. The contribution and interdependence of capsule and SeM to killing in equine blood and neutrophils were investigated in naturally occurring strains of Se. Strains CF32, SF463 were capsule and SeM positive, strains Lex90, Lex93 were capsule negative and SeM positive and strains Se19, Se1-8 were capsule positive and SeM deficient. Phagocytosis and killing of Se19, Se1-8, Lex90 and Lex93 in equine blood and by neutrophils suspended in serum were sig...
Waller AS.Strangles, caused by the host adapted Lancefield group C bacterium Streptococcus equi sub-species equi (S. equi), is one of the oldest recognised infectious diseases of horses and continues to cause significant welfare and economic cost throughout the world. The ability of S. equi to establish sub-clinical persistent infections primarily in the guttural pouches of convalescent horses has been instrumental to its success. However, the implementation of simple control measures that permit the identification and treatment of persistently infected carriers can prevent further outbreaks of disease ...
Sweeney CR, Benson CE, Whitlock RH, Meirs DA, Barningham SO, Whitehead SC, Cohen D.The age-specific attack rates of Streptococcus equi infections of the upper respiratory tract and lymph nodes (strangles) in horses for the different age groups were 17.6% for broodmares, 47.5% for 1-year-old horses, and 37.5% for foals. Streptococcus equi was isolated from nasal, pharyngeal, or lymph node specimens in 31 (60.8%) of 51 sick horses. A male 1-year-old horse, shipped from Kentucky to farm A, was considered to be the index case. Six (19.4%) of 31 horses with strangles remained as shedders of S equi after clinical signs of the disease had ended. Shedders of S equi were not identifi...
Milinovich GJ, Burrell PC, Pollitt CC, Bouvet A, Trott DJ.Four Gram-positive, catalase-negative, coccoid-shaped isolates were obtained from the caecum and rectum of horses with oligofructose-induced equine laminitis. Phenotypic and phylogenetic studies were performed on these isolates. Initial biochemical profiling assigned two of the isolates to Streptococcus bovis. The other two isolates, however, could not be assigned conclusively on the basis of their biochemical profiles. Gene sequence analysis demonstrated that the four new isolates were related most closely to Streptococcus suis based on the 16S rRNA gene and to Streptococcus orisratti based o...
Ikhuoso OA, Monroy JC, Rivas-Caceres RR, Cipriano-Salazar M, Barbabosa Pliego A.Although the strangles disease of Streptococcus equi was discovered many decades ago in 1,251 by Jordanus Ruffus, it has still remained a major frequently diagnosed infection in horses all over the world. The S. equi subspecies pathogen is known to be often resistant to antibiotic treatment, and it makes the antibiotics inefficient; hence, this review was conducted to study how the disease can be managed. The age-long sign of this infection is the oozing of pus through the mucous and skin membranes. Affected horses lose appetite, develop fever, and become depressed, which result in them losin...
Held J, Schmitz R, van der Linden M, Nührenberg T, Häcker G, Neumann FJ.Purulent pericarditis is a life-threatening disease that usually manifests following bacteraemia or through spreading from an intrathoracic focus. Only a few cases of this disease have been reported with Lancefield group C streptococci as aetiological agents, and the primary focus in these infections remains unknown. We report a case of purulent pericarditis with septic and cardiogenic shock, caused by Streptococcus equi subsp. zooepidemicus (group C) in a 51-year-old patient. The pathogen was possibly contracted through contact with horses. Most probably, it caused initially pneumonia before ...
Troedsson MH, Liu IK, Ing M, Pascoe J, Thurmond M.The electrical myometrial activity of three mares with a documented increased susceptibility to chronic uterine infection (CUI) and three mares considered to be resistant to CUI was investigated. Electrodes were surgically implanted in the myometrium of the mares and electrical activity was monitored by a Grass polygraph. Oestrus was determined by transrectal ultrasonography of the reproductive tract and teasing of the mares with a stallion. Findings were confirmed by blood progesterone concentrations 35 mm was detected, the uterus was infused with a genital strain of 5 x 10(6) Streptococcus ...
Hu D, Chao Y, Zhang B, Wang C, Qi Y, Ente M, Zhang D, Li K, Mok KM.Horse botflies have been a threat to the Przewalski's horses in the Kalamaili Nature Reserve in Xinjiang of China since their reintroduction to the original range. As larvae of these parasites could infest the intestine of a horse for months, they could interact with and alter the structure and composition of its intestinal microbiota, affecting adversely its health. Nonetheless, there are no such studies on the rewilded Przewalski's horses yet. For the first time, this study characterizes the composition of the intestinal microbiota of 7 rewilded Przewalski's horses infected severely by Gaste...
Riihimäki M, Aspán A, Ljung H, Pringle J.The aim of the study was to use culture, qPCR and seM sequencing to map Streptococcus equi subspec. equi (S.equi) isolates in long term carrier animals. A strangles outbreak affecting 41 Icelandic horses was followed to determine strangles free status using nasal and/or guttural pouch lavages collected serially on eleven separate occasions over 13 months. Ten persistent carriers, of which eight had repeated culture positive samples for S. equi, were selected for the study. Of 115 samples collected, 61 were S. equi positive on qPCR; from which 32 were also culture positive. Amplification of par...
El-Sheikh Ali H, Legacki EL, Loux SC, Esteller-Vico A, Dini P, Scoggin KE, Conley AJ, Stanley SD, Ball BA.The current study aimed to elucidate the mechanisms underlying myometrial activation during equine placentitis related to progestogens and the progesterone receptor signaling pathways. Placentitis was induced via intracervical inoculation with Streptococcus equi ssp zooepidemicus in mares at approximately 290 days of gestation (placentitis group; n = 6) with uninoculated gestationally matched mares as controls (n = 4). Mares in the placentitis and control groups were euthanized, and myometrial samples were collected from two regions: region 1-parallel to active placentitis lesion with plac...
Timoney JF, Yang J, Liu J, Merant C.Streptococcus equi (S. equi) causes equine strangles, a highly contagious and widespread purulent lymphadenitis of the head and neck. Highly resistant to phagocytosis, it produces long extracellular chains in affected lymph nodes. In a screen of clones reactive with convalescent serum from a gene library of S. equi CF32 we identified IdeE, an IgG-endopeptidase and homologue of the leucocyte receptor Mac-1 (CD11b). IdeE is expressed during S. equi infection eliciting both serum and mucosal antibody responses which persisted at significant levels in serum for over 200 days. Release from S. equi ...
Velineni S, Timoney JF.Streptococcus zooepidemicus of Lancefield group C is a highly variable tonsillar and mucosal commensal that usually is associated with opportunistic infections of the respiratory tract of vertebrate hosts. More-virulent clones have caused epizootics of severe respiratory disease in dogs and horses. The virulence factors of these strains are poorly understood. The antiphagocytic protein SeM is a major virulence factor and protective antigen of Streptococcus equi, a clonal biovar of an ancestral S. zooepidemicus strain. Although the genome of S. zooepidemicus strain H70, an equine isolate, conta...
Lakritz J, Wilson WD, Berry CR, Schrenzel MD, Carlson GP, Madigan JE.Twenty-three foals, between 1 and 7 months old, with signs of acute respiratory distress, were examined at the Veterinary Medical Teaching Hospital (VMTH), University of California, Davis, between 1984 and 1989. Characteristic features included sudden onset of severe respiratory distress and tachypnea, cyanosis unresponsive to nasal oxygen, pyrexia, hypoxemia, hypercapneic respiratory acidosis, poor response to treatment, and histopathologic lesions of bronchiolitis and bronchointerstitial pneumonia. Seven of the 23 foals were normal before the onset of respiratory distress, 3 foals were found...
Kudirkiene E, Welker M, Knudsen NR, Bojesen AM.Streptococcus equi includes very important animal and human pathogens. S. equi subsp. equi (SEE) is a highly pathogenic equine specific subspecies, while S. equi subsp. zooepidemicus (SEZ) and S. equi subsp. ruminatorum are opportunistic pathogens of various animal species and humans. Due to great phenotypic and sequence similarity between three subspecies their discrimination remains difficult. In this study, we aimed to design and validate a novel, Superspectra based, MALDI-TOF MS approach for reliable, rapid and cost-effective identification of SEE and SEZ, the most frequent S. equi subspec...
Macpherson ML.Equine placentitis, and resultant preterm labor, are important sources of fetal and neonatal loss. The primary cause of equine placentitis is infection of the placenta with Streptococcus equi subspecies zooepidemicus, which ascends through the caudal reproductive tract. Current treatment protocols for mares affected with placentitis are empirical. This paper reviews treatment approaches for resolving placentitis and preterm labor in both equine and non-equine species. Specific therapies reviewed include antimicrobial, anti-inflammatory, tocolytic, and progestin agents.
Malaluang P, Åkerholm T, Nyman G, Lindahl J, Hansson I, Morrell JM.An understanding of the normal bacterial microbiota of any organ is essential to provide the background to conditions and interventions that might cause the microbiota to change. In the vagina of the mare, a change of bacterial microbiota could be induced by introduction of semen, treatment with antibiotics, discharge from an unhealthy uterus etc. Previous studies on equine vaginal bacteria are not all conducted in the same way and results are not altogether consistent. Therefore, this study was designed to provide a deeper understanding of the bacterial microbiota of the mare vagina, and poss...
Waller AS.Strangles, characterised by pyrexia followed by abscessation of the lymph nodes of the head and neck, was first described in 1251 (Rufus 1251) and the causative agent, Streptococcus equi, was identified in 1888 (Schutz 1888). However, despite more than a century of research into this disease, strangles remains the most frequently diagnosed infection of horses with over 600 outbreaks being identified in the UK alone each year (Parkinson and others 2011). Here, Andrew Waller reviews some of the recent advances in the understanding of the evolution of S equi and puts this into the context of prev...
Mallicote M.There are few diseases that ignite as much fervor among horse owners as strangles. Streptococcus equi subsp equi (strangles) infections frequently require the treating veterinarian to manage not only the clinical cases but also the biosecurity and provision of information to all involved parties. Although the disease is typically characterized by low mortality and high morbidity, restrictions of horse movement that result from appropriate quarantine procedures often frustrate the involved parties. The aims of this article are to provide clinically relevant information for diagnosis, treatment,...
Timoney JF, Eggers D.An indirect test based on horse blood was used to study bactericidal responses of the horse to Streptococcus equi following infection or vaccination. Bactericidal antibody appeared in convalescent sera between two and four weeks and high titres were usually attained by eight weeks. Infection without clinical evidence of abscessation was also effective in eliciting strong bactericidal responses. Serum bactericidal activity of horses either recovered from strangles or immunised with commercial bacterin had declined eight months after vaccination. However, horses that developed strangles eight to...
Bailey CS, Macpherson ML, Pozor MA, Troedsson MH, Benson S, Giguere S, Sanchez LC, Leblanc MM, Vickroy TW.The objective was to determine if long-term treatment with trimethoprim sulfamethoxazole (antimicrobial), pentoxifylline (anti-inflammatory/anti-cytokine) and altrenogest (synthetic progestin), would improve pregnancy outcome in mares with experimentally induced placentitis. Seventeen normal, pregnant pony mares were enrolled in the study at 280-295 d of pregnancy. Placentitis was induced in all mares by intra-cervical inoculation of Streptococcus equi subsp. zooepidemicus (10(7) CFU). Five mares served as infected, untreated control animals (Group UNTREAT). Twelve mares (Group TREAT) were inf...
North SE, Wakeley PR, Mayo N, Mayers J, Sawyer J.Infection with Streptococcus equi subspecies equi (S. equi) is endemic in the UK. A proportion of horses serve as long-term carriers and act as a reservoir of infection. Detection of these persistently infected horses is difficult using standard culture techniques owing to a lack of sensitivity and overgrowth by contaminating bacteria. In addition, differentiation of this causative bacterium from the closely related S. equi zooepidemicus has made the development of reliable and accurate diagnostic tests difficult. Objective: To develop and validate a sensitive and specific real-time PCR assay ...
