Streptococcus hillyeri isolated from septic pleuritis in a horse.
Abstract: 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 was made, and the horse was immediately started on a course of broad-spectrum antibiotics, a NSAID, an anticoagulant, and intravenous fluids. Despite intensive care, the clinical parameters deteriorated, and the horse was euthanized 6 d later. Cytology confirmed septic pleuritis, with short chains or groups of coccoid bacteria. Anaerobic culture yielded gram-positive cocci from both hemithoraces in almost pure culture, which we identified as S. hillyeri by 16S rDNA and whole-genome analysis. Additionally, we identified 4 previously unassigned Streptococcus sp. sequences as S. hillyeri. Of these, 3 were obtained from aborted equine fetuses and a fourth from a donkey mastitis case, supporting the pathogenic nature of S. hillyeri in these host species.
Publication Date: 2025-01-07 PubMed ID: 39773117PubMed Central: PMC11707762DOI: 10.1177/10406387241306724Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Case Reports
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research study pertains to a case where Streptococcus hillyeri was isolated from a horse suffering from septic pleuritis. This bacterium’s presence was confirmed through various tests and analyses, raising potential implications regarding its role in causing disease in horses.
Case Background and Symptom Observations
- The preliminary part of the paper describes the case of a 17-year-old Hungarian Sport Horse mare that was brought to the University of Veterinary Medicine in Budapest, Hungary with suspected pleuritis (inflammation of the membrane enveloping the lungs).
- Upon examination, the horse was found to have high fever, tachycardia (abnormally fast heart rate), severe difficulty in inspiration, and tachypnea (excessively fast breathing).
- Further diagnostics carried out using thoracic ultrasonography indicated that the horse suffered from severe pleural effusion (fluid accumulation around the lungs) and lung consolidation (a condition where a part or the whole lung becomes solid due to inflammation or damage).
Diagnostic Tests and Treatments
- Following the clinical examinations, both sides (hemithoraces) of the horse’s chest were sampled and 66 liters of cloudy fluid indicative of an infection was extracted.
- The horse was diagnosed with septic pleuritis and immediately put on broad-spectrum antibiotics, NSAIDs (Non-Steroidal Anti-Inflammatory Drugs), anticoagulants, and intravenous fluids as a course of treatment.
- Despite these intensive measures, the horse’s condition worsened, leading to euthanasia after six days.
Postmortem Analysis
- The horse’s fluid sample confirmed the diagnosis of septic pleuritis, with the presence of coccoid bacteria (spherical, oval, or generally roundish bacteria).
- An anaerobic culture (a culture devoid of oxygen), revealed Gram-positive cocci (spherical-shaped bacteria classified by their positive reaction to the Gram stain test) in almost pure culture, in samples from both hemithoraces.
- Application of 16S rDNA and whole genome analyses identified the bacteria as Streptococcus hillyeri, confirming its presence in the horse’s thoracic sample.
Additional Findings
- This study also identified four prior unclassified Streptococcus species sequences as Streptococcus hillyeri. These sequences were derived from aborted equine fetuses and a donkey suffering from mastitis (inflammation of the breast or udder), highlighting a possibility that Streptococcus hillyeri may be a pathogen in these species.
Cite This Article
APA
Albert E, Biksi I, Laczkó L, Miló L, Cseri K, Bőkényné Tóth R, Papp D, Halmay D, Bódai E, Bakos Z.
(2025).
Streptococcus hillyeri isolated from septic pleuritis in a horse.
J Vet Diagn Invest, 37(2), 393-397.
https://doi.org/10.1177/10406387241306724 Publication
Researcher Affiliations
- Departments of Pathology, University of Veterinary Medicine Budapest, Üllő, Hungary.
- Institute of Metagenomics, University of Debrecen, Debrecen, Hungary.
- Departments of Pathology, University of Veterinary Medicine Budapest, Üllő, Hungary.
- One Health Institute, University of Debrecen, Debrecen, Hungary.
- HUN-REN-UD Conservation Biology Research Group, University of Debrecen, Debrecen, Hungary.
- One Health Institute, University of Debrecen, Debrecen, Hungary.
- One Health Institute, University of Debrecen, Debrecen, Hungary.
- One Health Institute, University of Debrecen, Debrecen, Hungary.
- One Health Institute, University of Debrecen, Debrecen, Hungary.
- Vet-Med-Labor, Budapest, Hungary.
- Clinic of Equine Medicine, University of Veterinary Medicine Budapest, Üllő, Hungary.
- Clinic of Equine Medicine, University of Veterinary Medicine Budapest, Üllő, Hungary.
MeSH Terms
- Animals
- Horses
- Horse Diseases / microbiology
- Horse Diseases / diagnosis
- Pleurisy / veterinary
- Pleurisy / microbiology
- Female
- Streptococcal Infections / veterinary
- Streptococcal Infections / microbiology
- Streptococcus / isolation & purification
- Streptococcus / genetics
- Streptococcus / classification
Conflict of Interest Statement
Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
References
This article includes 16 references
- Arroyo MG. Factors associated with survival in 97 horses with septic pleuropneumonia.. J Vet Intern Med 2017;31:894–900.
- Bond S. Topography of the respiratory, oral, and guttural pouch bacterial and fungal microbiotas in horses.. J Vet Intern Med 2023;37:349–360.
- Davis EG, Rush BR. Diagnostic challenges: equine thoracic neoplasia.. Equine Vet Educ 2013;25:96–107.
- Erol E. Beta-hemolytic Streptococcus spp. from horses: a retrospective study (2000–2010).. J Vet Diagn Invest 2012;24:142–147.
- Foster G. Streptococcus caledonicus sp. nov., isolated from sheep.. Int J Syst Evol Microbiol 2020;70:2611–2615.
- Kim M. Towards a taxonomic coherence between average nucleotide identity and 16S rRNA gene sequence similarity for species demarcation of prokaryotes.. Int J Syst Evol Microbiol 2014;64:346–351.
- MacFadyen AC. Streptococcus hillyeri sp. nov., isolated from equine trachea.. Int J Syst Evol Microbiol 2019;69:3009–3013.
- Padalino B. Behaviour during transportation predicts stress response and lower airway contamination in horses.. PLoS One 2018;13:e0194272.
- Podico G. A novel Streptococcus species causing clinical mastitis in a pregnant donkey.. J Vet Diagn Invest 2021;33:979–983.
- Racklyeft DJ, Love DN. Bacterial infection of the lower respiratory tract in 34 horses.. Aust Vet J 2000;78:549–559.
- Reed SM. Equine Internal Medicine.. 4th ed. Elsevier, 2018.
- Reuss SM, Giguère S. Update on bacterial pneumonia and pleuropneumonia in the adult horse.. Vet Clin North Am Equine Pract 2015;31:105–120.
- Sweeney CR. Anaerobic bacteria in 21 horses with pleuropneumonia.. J Am Vet Med Assoc 1985;187:721–724.
- Sweeney CR. Aerobic and anaerobic bacterial isolates from horses with pneumonia or pleuropneumonia and antimicrobial susceptibility patterns of the aerobes.. J Am Vet Med Assoc 1991;198:839–842.
- Tomlinson JE. The association of fibrinous pleural effusion with survival and complications in horses with pleuropneumonia (2002–2012): 74 cases.. J Vet Intern Med 2015;29:1410–1417.
- Wood JLN. Association between respiratory disease and bacterial and viral infections in British racehorses.. J Clin Microbiol 2005;43:120–126.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
