Key points are not available for this paper at this time.
Nissle 1917 is sold as a probiotic and considered safe even though it has been known since 2006 that it harbors the genes for colibactin synthesis. Colibactin is a potent genotoxin that is now linked to causative mutations found in human colorectal cancer.
Nougayrède et al. (Wed,) studied this question.