# High genetic similarity between Clostridioides difficile isolates from a woman with community-acquired infection and her dog

**Authors:** Júlia Meireles, Suzana Leite, Amanda Macedo Trindade de Castro Brandt, Geraldo Alves Neto, Rodrigo Otávio Silveira Silva, Eliane de Oliveira Ferreira

PMC · DOI: 10.3389/fpubh.2025.1755562 · 2026-01-09

## TL;DR

A woman and her dog had genetically similar C. difficile infections, suggesting possible transmission or shared exposure outside of hospitals.

## Contribution

The study presents evidence of potential zoonotic transmission or shared exposure of C. difficile between humans and pets.

## Key findings

- The human and dog isolates had the same ribotype and only four SNP differences.
- This genetic similarity suggests shared exposure or transmission between the woman and her dog.
- The case highlights the need to explore companion animals as sources of community C. difficile.

## Abstract

Clostridioides difficile infection is a leading cause of diarrhea associated with healthcare settings, but its incidence in the community has increased substantially in recent years, raising questions about possible non-hospital reservoirs. We report a case of community-acquired C. difficile infection in a woman and the concurrent isolation of a toxigenic strain from her dog, which also presented diarrhea. Both isolates showed the same ribotype and differed by only four single-nucleotide polymorphisms in whole-genome sequencing analysis, indicating a high degree of genetic similarity. These findings suggest the possibility of shared exposure or transmission between the patient and her dog and highlight the need to further investigate companion animals as potential sources of community-acquired C. difficile.

## Linked entities

- **Diseases:** diarrhea (MONDO:0001673)
- **Species:** Clostridioides difficile (taxon 1496)

## Full-text entities

- **Diseases:** C. difficile infection (MESH:D003015), infection (MESH:D007239), diarrhea (MESH:D003967)
- **Species:** Canis lupus familiaris (dog, subspecies) [taxon 9615], Clostridioides difficile (species) [taxon 1496], Homo sapiens (human, species) [taxon 9606]

## Figures

1 figure with captions in the complete paper: https://tomesphere.com/paper/PMC12827726/full.md

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Source: https://tomesphere.com/paper/PMC12827726