Environmental distribution and diversity of Bacillus thuringiensis in Spain.

Bacillus thuringiensis was isolated from 301 out of 1,005 samples collected in Spain from agricultural and non-cultivated soils, dust from stored products, and dead insects. Based on the production of parasporal crystals, 1,401 isolates were identified as B. thuringiensis after examining 11,982 B. thuringiensis-like colonies. We found a greater presence of B. thuringiensis in dust from grain storages than in other habitats. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the spore-crystal mixtures revealed diverse populations of B. thuringiensis which were differentiated in at least 92 distinct protein profiles. Serological identification also showed great diversity among the S…