A powerful superbug can cross-contaminate between pigs and humans

Antibiotics have saved countless lives around the world, and their efficiency on particular diseases cannot be overlooked. However, excessive or uncontrolled use of antibiotics on farms is a worrying problem that negatively affects both animals' and humans' health since it reinforces antibiotic resistance.

A recent study on Clostridioides difficile superbug has revealed that antibiotic-resistant bugs can transmit from pigs to humans. 

The study, conducted by scientists from the University of Copenhagen and Statens Serum Institut in Denmark, was presented at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Lisbon, Portugal. At this moment, there isn't a full paper since the research has not yet been submitted to a medical journal for publication.

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“Our finding of multiple and shared resistance genes indicate that C. difficile is a reservoir of antimicrobial resistance genes that can be exchanged between animals and humans”, Dr. Semeh Bejaoui, a Ph.D. student at the University of Copenhagen and one of the authors of the study, stated in a press release. “This alarming discovery suggests that resistance to antibiotics can spread more widely than previously thought and confirms links in the resistance chain leading from farm animals to humans.”

“The overuse of antibiotics in human medicine and as cheap production tools on farms is undoing our ability to cure bacterial infections,” said Dr. Bejaoui. “Of particular concern is the large reservoir of genes conferring resistance to aminoglycosides, a class of antibiotics to which C. difficile is intrinsically resistant – they are not needed for resistance in this species. C. difficile thus plays a role in spreading these genes to other susceptible species”

What does C. difficile do, and how do you catch it?

Clostridioides difficile is a bacterium that is resistant to numerous antibiotics. It is known to be one of the world’s biggest threats in terms of antibiotic resistance. It infects the human gut and leads to the emergence of damaging inflammation in the gut. It can also cause fever, kidney failure, and severe diarrhea.

Generally, C. difficile-related illnesses occur due to the frequent use of antibiotic medications. It is estimated that about 200,000 people are infected annually with C. difficile in the United States. But in recent, these numbers have decreased thanks to improved prevention measures.

The process included taking samples of Clostridioides difficile from 14 pig farms in Denmark, and then the researchers screened those samples for C. difficile. It turned out that out of 514 pigs samples, 54 had evidence of C. difficile and that animal to human (zoonotic) transmission of antimicrobial resistance genes is possible.

“This study provides more evidence on the evolutionary pressure connected with the use of antimicrobials in animal husbandry, which selects for dangerously resistant human pathogens. This highlights the importance of adopting a more comprehensive approach, for the management of C. difficile infection, in order to consider all possible routes of dissemination,” Dr. Bejaoui added.