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Toxin-producing ability among Bacillus spp. outside the Bacillus cereus group
Cecilie From1, Rudiger Pukall, Peter Schumann
1Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, PO Box 8146, Dep, NO-0033 Oslo, Norway.
Applied and Environmental Microbiology
|March 5, 2005
Summary
Eight Bacillus strains from food and water produced toxins, including cytotoxic and emetic types, identified as B. subtilis, B. mojavensis, B. pumilus, or B. fusiformis. These toxins showed varying stability to heat and concentration methods.
Area of Science:
- Food microbiology
- Bacterial toxins
- Food safety
Background:
- Bacillus species are ubiquitous in food and environmental samples.
- Some Bacillus species produce toxins that can cause foodborne illnesses.
- Characterizing these toxins is crucial for public health.
Purpose of the Study:
- To investigate the production of enterotoxins and emetic toxins by Bacillus species isolated from various sources.
- To identify the specific Bacillus species responsible for toxin production.
- To characterize the properties of the produced toxins.
Main Methods:
- Isolation and identification of Bacillus species from food, water, and food plants.
- Toxin detection using cytotoxicity assay on Vero cells and boar spermatozoa motility assay.
- Liquid chromatography-mass spectrometry (LC-MS) for toxin analysis.
- Polyphasic identification including biochemical, chemotaxonomic, and DNA-based analyses.
- Assessment of toxin stability under different conditions (temperature, concentration).
Main Results:
- Eight out of 333 Bacillus strains produced detectable toxins.
- Six strains were cytotoxic, three produced putative emetic toxins, and one produced both.
- Toxin-producing strains belonged to B. subtilis, B. mojavensis, B. pumilus, and B. fusiformis.
- Cytotoxin activity varied with concentration methods and heat treatment.
- B. mojavensis strains showed cytotoxin production across a wide temperature range (25-42°C).
- Emetic toxin production was optimal at 22-30°C.
- No B. cereus-like enterotoxins were detected.
Conclusions:
- Certain Bacillus species other than B. cereus can produce cytotoxic and emetic toxins.
- The identified Bacillus species (B. subtilis, B. mojavensis, B. pumilus, B. fusiformis) are potential sources of food contamination.
- Understanding toxin production and stability is vital for food safety risk assessment.