Effects of Bile Acids and Nisin on the Production of Enterotoxin by Clostridium perfringens in a Nutrient-Rich Medium.

Miseon Park,Fatemeh Rafii

doi:10.1155/2018/7276523

Abstract

Clostridium perfringens is the second most common cause of bacterial foodborne illness in the United States, with nearly a million cases each year. C. perfringens enterotoxin (CPE), produced during sporulation, damages intestinal epithelial cells by pore formation, which results in watery diarrhea. The effects of low concentrations of nisin and bile acids on sporulation and toxin production were investigated in C. perfringens SM101, which carries an enterotoxin gene on the chromosome, in a nutrient-rich medium. Bile acids and nisin increased production of enterotoxin in cultures; bile acids had the highest effect. Both compounds stimulated the transcription of enterotoxin and sporulation-related genes and production of spores during the early growth phase. They also delayed spore outgrowth and nisin was more inhibitory. Bile acids and nisin enhanced enterotoxin production in some but not all other C. perfringens isolates tested. Low concentrations of bile acids and nisin may act as a stress signal for the initiation of sporulation and the early transcription of sporulation-related genes in some strains of C. perfringens, which may result in increased strain-specific production of enterotoxin in those strains. This is the first report showing that nisin and bile acids stimulated the transcription of enterotoxin and sporulation-related genes in a nutrient-rich bacterial culture medium.

Highlights

Clostridium perfringens, an ubiquitous, anaerobic sporeforming bacterium found in the gastrointestinal tract of humans and animals and in soil, produces various toxins and can cause a variety of mild to severe, even lethal, infections in humans and animals [1]
We have investigated the effects of low concentrations of bile acids and nisin on induction of sporulation, enterotoxin production in medium suitable for vegetative growth, and spore outgrowth
To determine the effects of bile acids and nisin on growth, spore production, and germination in C. perfringens SM101, the cells and germinating spores in samples taken at various intervals during 24 h incubation, in brain heart infusion (BHI) alone or BHI containing either 100 μg/ml (0.24 mM) of bile acids or 1 μg/ml (0.3 μM) of nisin, were counted and compared

Summary

Introduction

Clostridium perfringens, an ubiquitous, anaerobic sporeforming bacterium found in the gastrointestinal tract of humans and animals and in soil, produces various toxins and can cause a variety of mild to severe, even lethal, infections in humans and animals [1]. Some C. perfringens type A strains that produce an enterotoxin, CPE, cause food poisoning [2,3,4]. The enterotoxin binds to the intestinal epithelial cell receptors (claudins) and becomes part of a complex that is oligomerized and inserted into an epithelial cell membrane [7,8,9]. This results in pore formation, causing cell damage due to increased permeability, manifested by watery diarrhea and stomach cramps [1, 6]. The gene encoding the enterotoxin CPE may be located on either the chromosome or the plasmid [14, 15]

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Conclusion