The occurrence and properties of Bacillus thuringiensis isolated from free-living animals

AIMS: To assess the prevalence and properties of Bacillus thuringiensis isolated from the intestines of small mammals. METHODS AND RESULTS: Bacillus thuringiensis was found in 11% of rodents and 17% of insectivores. Using PFGE of chromosomal DNA, SDS-PAGE of whole-cell proteins and biochemical tests (API system), 12 isolates and three reference strains were classified. Numerical analysis revealed 61% and 89% similarity of protein profiles and biochemical properties of the bacilli, respectively. The results of PFGE were consistent with the outcomes of the analysis of protein profiles. CONCLUSIONS: Although B. thuringiensis is not common in the intestines of small mammals, it is heterogeneous at the genotypic and phenotypic level. SIGNIFICANCE AND IMPACT OF THE STUDY: The results presented here help to explain the diversity and the ecological significance of B. thuringiensis. Future study should focus on the toxic activity of the isolated strains.