Food poisoning is a common, yet unpleasant, illness caused by eating contaminated items. It is sometimes caused by Clostridium perfringens, a pathogen widely found in soil and the intestinal tracts of animals.

The pathogen multiplies in environments with little oxygen, for example, curry stored in a pot. After ingestion of the pathogen, they form spores in the small intestinal tracts. The toxins produced during spore formation cause diarrhea and abdominal pain, but the underlying mechanism of spore formation has not been fully understood.

Associate Professor Mayo Yasugi’s team at Osaka Metropolitan University’s Graduate School of Veterinary Science has examined how amino acids are involved in Clostridium perfringens spore formation. In this study, they created 21 culture mediums, 20 of which were each deprived of one of the amino acids that make proteins in the human body, to evaluate the pathogen’s development.

As a result, the team identified serine as an inhibitor of Clostridium perfringens spore formation. When observed under a microscope, it was found that serine inhibits the pathogen’s cell wall from remodeling, which is necessary in the process of becoming a spore.

“This is the first reported case where a single amino acid inhibits spore-forming anaerobic bacteria,” stated Professor Yasugi. “In the future, we hope to understand serine inhibition, the pathogenic mechanisms of Clostridium perfringens food poisoning, and the survival strategies of pathogenic microorganisms in the human body. Hopefully, this will lead to academic contributions to microbiology and infectious diseases.”

The findings were published in Anaerobe.

Funding
This work was supported in part by JSPS KAKENHI Grant Numbers 19K10580 and 23K09674 to M.Y.

Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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