Cereulide

Cereulide is a toxin produced by certain strains of Bacillus cereus, a bacterium commonly found in soil and food. It is responsible for the emetic form of foodborne illness associated with Bacillus cereus contamination. Cereulide is described as a cyclic peptide toxin, specifically a cyclic depsipeptide, formed by nonribosomal peptide pathways. It is notably thermostable, meaning it can survive cooking temperatures that would destroy many other toxins or microbes.

The primary mechanism of cereulide is as a potassium ionophore that can disrupt cellular and mitochondrial membranes. By transporting potassium ions across membranes, it dissipates the membrane potential, leading to mitochondrial dysfunction and energy depletion in affected cells. This rapid cellular disturbance is linked to the vomiting reflex and the rapid onset of symptoms observed after ingestion.

Clinically, cereulide exposure leads to the emetic syndrome, characterized mainly by nausea and vomiting, often with abdominal cramps. Onset is typically rapid, occurring within 30 minutes to a few hours after consuming contaminated food. The illness is usually self-limited, resolving within about 24 hours, with supportive care the mainstay of treatment. There is no specific antidote for cereulide poisoning.

Foods associated with cereulide contamination are often rice and other prepared foods that have been cooked and then kept warm for extended periods, allowing Bacillus cereus to grow and produce the toxin. Prevention focuses on preventing bacterial growth and toxin formation through proper cooking, rapid cooling, and safe food storage. Detection in food or clinical samples is achieved using analytical methods such as liquid chromatography–mass spectrometry.