Clostridioides difficile infection: an emerging zoonosis?

ABSTRACT

Introduction

Clostridioides difficile (C. difficile) infection (CDI) is the most common cause of antibiotic-associated diarrhea and one of the common infections in healthcare facilities. In recent decades, there has been an emerging threat of community-acquired CDI (CA-CDI). Environmental transmission of C. difficile in the community setting has become a major concern, and animals are an important reservoir for C. difficile causing human diseases.

Areas covered

In this article, the molecular epidemiology of C. difficile in animals and recent evidences of zoonotic transfer to humans are reviewed based on an electronic search in the databases of PubMed and Google Scholar.

Expert opinion

C. difficile can be found in stool from diarrheal dogs and cats; therefore, household pets could be a potential source. C. difficile will threaten human health because hypervirulent C. difficile ribotype 078 strains have been found in retail chickens, pig farms, and slaughterhouses. Risk factors for fecal C. difficile carriage in animals include young age, dietary changes, and antibiotic abuse in domestic animals. With the advent of whole genome sequencing techniques, there will be more solid evidence indicating zoonotic transfer of C. difficile from animals to humans.

KEYWORDS:

• Clostridioides difficile
• toxigenic
• zoonosis
• livestock
• poultry
• seafood
• pets

Article highlights

• There is increasing concern for community-associated Clostridioides difficile infection (CDI) and a growing number of reports on CDI in animals. The potential for zoonotic transmission cannot be overemphasized.

• Asymptomatic carriage of C. difficile toxigenic strains pathogenic to humans was noted in household pets.

• Exposure to pastures, slaughterhouses, or meat processing of livestock have been associated with the risk of C. difficile transmission to humans.

• Risk factors for C. difficile colonization in livestock include exposure to individuals susceptible to CDI, exposure to environments contaminated with C. difficile, dietary changes, and antibiotic abuse.

• Hypervirulent C. difficile strains including RT 078, 126, and 127 are found in pig farms. Moreover, there is genetic relatedness between RT 078 isolates from patients and pigs, indicative of zoonotic transfer to human.

• Seafood could be contaminated by C. difficile, but the transmission from seafood to humans is not well confirmed.

• Whole genome sequencing proves objective evidence suggestive of mutual spread of RT 078, 014, and 046 between animals and humans.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

The present study was supported by research grants from the Ministry of Science and Technology, Taiwan (MOST 109-2314-B-006-089-MY3 and 110-2314-B-675-001).