Isolation and characterization of Bacillus thuringiensis (Bacillaceae: Bacillales) strains from an urban environment.

Bacillus thuringiensis (Ishiwata, 1901; Berliner, 1915) produces parasporal inclusions prior to spore formation; these inclusions are insecticidal. Therefore, B. thuringiensis is used as a microbial pesticide. B. thuringiensis has been detected conventionally in the natural environment, such as in the soil and on plant surfaces as well as in farms and natural fields. To date, the detection rate of B. thuringiensis (the BT index) with standard methods is very low. In this study, we developed a highly efficient detection method to isolate B. thuringiensis from urban environments. In our experiments, The urban environment used was defined as the campus of the College of Bioresource Sciences at Nihon University. The urban samplings were composed of a mixed microbe layer including B. thuringiensis. The BT index was consistently >50% in this study. Our results suggested that the urban environment we examined is a reservoir of many varieties of B. thuringiensis. [ABSTRACT FROM AUTHOR]