Specialised laboratory for spore formers

The work of the Specialised laboratory for spore formers focuses on food safety issues with regard to the occurrence of species of the Bacillus (B.) cereus group, Clostridium (C.) botulinum, C. perfringens and Clostridioides difficile in food.

Bacillus cereus group

Species belonging to the B. cereus group (B. cereus sensu lato (s.l.)) are facultatively anaerobic, gram-positive, spore-forming bacteria, which are prevalent in the environment worldwide. Due to the persistence of the spores, food contamination cannot be completely avoided. Low contamination rates with spores or cells are usually not problematic; however, improper storage conditions might facilitate the outgrowth of spores and multiplication of bacterial cells in the food. With the consumption of food contaminated with B. cereus (s.l.), bacterial cells and/or toxins are ingested, which can lead to diarrhea and/or nausea and vomiting. Rapid cooling or sufficient hot holding of heated food can prevent the multiplication of the bacterium.

Clostridia

Clostridia are gram-positive, spore-forming rod-shaped bacteria. Most clostridia species are strict anaerobes, which can pose a challenge for laboratory diagnostics. The spores are ubiquitous and very resilient. Due to the wide distribution, food can be contaminated with clostridial spores. When prepared and stored correctly,minor contamination of food usually does not pose a risk. Clostridia can cause infections in humans and animals via the formation of toxins. These toxins can either be formed in the food and lead to a direct intoxication after consumption (e.g. botulism), or ingested spores outgrow to multiplying cells in the digestive tract, which then form disease-causing toxins. Symptoms range from abdominal cramps and diarrhea (C. perfringens, Clostridioides difficile) to severe neurological symptoms like vision disorders, difficulties in swallowing and paralysis of muscles (botulinum neurotoxins).

Focus of research at the Specialised laboratory for spore formers

• Establishment and optimisation of methods for the investigation of the pathogenic potential of clostridia and bacteria of the B. cereus group
• Studies on prevalence and characterisation of Clostridioides difficile and B. cereus (s.l.) in selected foods
• Further development of isolation methods for Clostridioides difficile from different matrices
• Collaboration regarding the establishment of replacement methods of animal experiments for the detection of botulinum neurotoxins

Additional functions to support the official food control laboratories in Germany

• Microbial and molecular characterisation of provided isolates (clostridia and bacteria of the B. cereus group), including NGS
• Involvement in national monitoring programs
• Detection of cereulid in food in cooperation with the NRL for the Monitoring of Marine Biotoxins
• Strain collection
• Support and advice

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