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Canadian journal of veterinary research = Revue canadienne de recherche veterinaire2026; 90(3); 111-117;

Prevalence of Clostridioides difficile in hospitalized neonatal mare-foal pairs from Alberta and direct comparison of fecal culture with toxin gene detection.

Abstract: is an important pathogen in the feces of adult horses and foals. It can be clinically diagnosed using several testing methods, including culture isolation and, more commonly, direct toxin gene detection from feces using molecular methods. The importance of monitoring shedding in foals or dams during hospitalization remains unclear. The objectives of this study were to determine the prevalence of fecal shedding in mare-foal pairs and to compare detection using isolation and a commercial real-time polymerase chain reaction (qPCR) for toxin A and B genes in feces. Foals and their mares admitted to a veterinary hospital were enrolled in the study and their fecal samples were tested for toxin A and B genes using qPCR and by culture using selective media. A total of 66 mare-foal pairs was included. Overall, fecal qPCR for toxin A and B genes was positive in 29/132 samples from mares and foals and all positive samples originated from foal fecal samples (29/66). A total of 95 samples were negative on both testing modalities (61 mares and 34 foals) and 24 samples were positive on both tests (24 foals). Eight samples (5 mares and 3 foals) were culture positive and qPCR negative, although all of the culture isolates were positive for A and B genes on subsequent conventional PCR testing. Five samples were positive for toxin genes using qPCR and negative using culture. The most common ribotype detected was 078. Two mare-foal pairs cultured positive, of which one pair shared the same ribotype. est un agent pathogène important présent dans les fèces des chevaux adultes et des poulains. Son diagnostic clinique repose sur plusieurs méthodes, notamment l’isolement par culture et, plus fréquemment, la détection directe des gènes de toxines dans les fèces par des méthodes moléculaires. L’importance du suivi de l’excrétion de chez les poulains et leurs mères hospitalisés reste incertain. Cette étude visait à déterminer la prévalence de l’excrétion fécale de chez les couples jument-poulain et à comparer la détection par isolement et détection des gènes des toxines A et B dans les fèces par PCR quantitative en temps réel (qPCR) commerciale. Les poulains et leurs juments admis dans un hôpital vétérinaire ont été inclus dans l’étude et leurs échantillons fécaux ont été analysés pour la recherche des gènes des toxines A et B de par qPCR et par culture sur milieux sélectifs. Au total, 66 paires jument-poulain ont été inclus. Globalement, la qPCR fécale pour les gènes des toxines A et B de s’est révélée positive dans 29/132 échantillons provenant de juments et de poulains, tous les échantillons positifs étant issus de fèces de poulains (29/66). Au total, 95 échantillons étaient négatifs aux deux tests (61 juments et 34 poulains) et 24 échantillons étaient positifs aux deux tests (24 poulains). Huit échantillons (5 juments et 3 poulains) étaient positifs en culture et négatifs en qPCR, bien que tous les isolats de culture aient été positifs pour les gènes A et B lors de tests PCR conventionnels ultérieurs. Cinq échantillons étaient positifs pour les gènes des toxines en qPCR et négatifs en culture. Le ribotype le plus fréquemment détecté était le 078. Deux paires jument-poulain ont présenté une culture positive, dont une paire partageant le même ribotype.(Traduit par Docteur Serge Messier).
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Publication Date: 2026-07-01 PubMed ID: 42460136PubMed Central: PMC13370171
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  • Journal Article

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.

Overview

  • This study investigated how common Clostridioides difficile (C. difficile) shedding is in hospitalized mare-foal pairs and compared two methods—fecal culture and real-time PCR (qPCR)—for detecting the bacterium’s toxin genes in feces.

Background

  • Clostridioides difficile is a bacterium known to cause disease in adult horses and foals, particularly in hospital settings.
  • It produces toxins A and B, which are the primary virulence factors responsible for symptoms.
  • Diagnostic methods typically involve:
    • Culture isolation of the bacterium from feces.
    • Molecular detection of toxin genes (A and B) directly from fecal samples using qPCR.
  • The clinical importance of monitoring fecal shedding of C. difficile in hospitalized foals and their mares is not well established.

Study Objectives

  • Determine the prevalence of fecal shedding of C. difficile in hospitalized mare-foal pairs.
  • Compare the detection results of two methods: the culture isolation method and a commercial real-time PCR assay for toxin A and B genes.

Methods

  • Subjects: 66 mare-foal pairs admitted to a veterinary hospital in Alberta.
  • Sample Collection: Fecal samples collected from both mares and foals.
  • Testing Procedures:
    • Culturing of feces on selective media to isolate C. difficile bacteria.
    • Commercial real-time PCR (qPCR) to detect toxin A and B genes directly in feces.
    • Subsequent conventional PCR testing on culture isolates to confirm toxin genes.

Key Findings

  • Prevalence by qPCR: 29 positive samples for toxin genes out of 132 total (66 mares + 66 foals), and all positives were from foals (29/66 foals positive).
  • Culture and qPCR concordance:
    • 95 samples were negative by both culture and qPCR (61 mares and 34 foals).
    • 24 samples were positive by both methods (all 24 from foals).
  • Discrepant results:
    • Eight samples (5 mares and 3 foals) were culture-positive but qPCR-negative; however, toxin genes were confirmed in these isolates via conventional PCR after culture.
    • Five samples were qPCR-positive but culture-negative, indicating that sometimes molecular detection is more sensitive or culture conditions may not always recover bacteria.
  • Ribotyping results:
    • The most common ribotype detected was 078, a ribotype known to cause disease in animals and humans.
    • Two mare-foal pairs had culture-positive isolates, and in one pair, both shared the same ribotype, suggesting possible transmission or common source.

Interpretation and Importance

  • The study highlights that C. difficile shedding was observed exclusively in foals and not in mares via qPCR, although some mares were culture-positive.
  • Both detection methods have value but may differ in sensitivity; thus, combining culture and molecular testing gives a more complete picture.
  • The presence of common ribotypes between mare and foal pairs suggests potential transmission during hospitalization or a shared environment.
  • The findings emphasize the need for monitoring C. difficile shedding in hospitalized foals, as this could impact infection control and clinical outcomes.

Limitations and Considerations

  • The study is limited to hospitalized mare-foal pairs from a single region (Alberta), so prevalence may vary elsewhere.
  • Discrepancies between culture and molecular detection indicate that each test may have limitations, such as culture sensitivity and PCR inhibitors.
  • Further research is necessary to assess the clinical implications of shedding and potential transmission dynamics in hospital settings.

Cite This Article

APA
Whitehead AE, Borges AS, Zakia LS, Yu S, Surette MG, Arroyo LG. (2026). Prevalence of Clostridioides difficile in hospitalized neonatal mare-foal pairs from Alberta and direct comparison of fecal culture with toxin gene detection. Can J Vet Res, 90(3), 111-117.

Publication

Canadian journal of veterinary research = Revue canadienne de recherche veterinaire
ISSN: 1928-9022
NlmUniqueID: 8607793
Country: Canada
Language: English
Volume: 90
Issue: 3
Pages: 111-117

Researcher Affiliations

Whitehead, Ashley E
  • Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta T3R 1J3 (Whitehead); Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1 (Borges, Zakia, Yu, Arroyo); Department of Medicine, Farncombe Family Digestive Health Research Institute, Health Sciences Centre, McMaster University, Hamilton, Ontario L8S 4K1 (Surette).
Borges, Alexandre S
  • Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta T3R 1J3 (Whitehead); Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1 (Borges, Zakia, Yu, Arroyo); Department of Medicine, Farncombe Family Digestive Health Research Institute, Health Sciences Centre, McMaster University, Hamilton, Ontario L8S 4K1 (Surette).
Zakia, Luiza S
  • Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta T3R 1J3 (Whitehead); Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1 (Borges, Zakia, Yu, Arroyo); Department of Medicine, Farncombe Family Digestive Health Research Institute, Health Sciences Centre, McMaster University, Hamilton, Ontario L8S 4K1 (Surette).
Yu, Serena
  • Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta T3R 1J3 (Whitehead); Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1 (Borges, Zakia, Yu, Arroyo); Department of Medicine, Farncombe Family Digestive Health Research Institute, Health Sciences Centre, McMaster University, Hamilton, Ontario L8S 4K1 (Surette).
Surette, Michael G
  • Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta T3R 1J3 (Whitehead); Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1 (Borges, Zakia, Yu, Arroyo); Department of Medicine, Farncombe Family Digestive Health Research Institute, Health Sciences Centre, McMaster University, Hamilton, Ontario L8S 4K1 (Surette).
Arroyo, Luis G
  • Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta T3R 1J3 (Whitehead); Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1 (Borges, Zakia, Yu, Arroyo); Department of Medicine, Farncombe Family Digestive Health Research Institute, Health Sciences Centre, McMaster University, Hamilton, Ontario L8S 4K1 (Surette).

MeSH Terms

  • Animals
  • Horses
  • Female
  • Feces / microbiology
  • Horse Diseases / epidemiology
  • Horse Diseases / microbiology
  • Clostridioides difficile / isolation & purification
  • Clostridioides difficile / genetics
  • Clostridium Infections / veterinary
  • Clostridium Infections / epidemiology
  • Clostridium Infections / microbiology
  • Bacterial Toxins / genetics
  • Bacterial Toxins / metabolism
  • Prevalence
  • Animals, Newborn
  • Alberta / epidemiology
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Enterotoxins / genetics

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