2007 年 53 巻 4 号 p. 486-490
In urban rivers in Osaka, Japan, DNA containing the stx2 gene, which encodes the Shiga toxin 2 (Stx2), was found to be present in sediment, even when it was not detected in the surface water. A DNA sequence similar to that of bacteriophage 933W and the Sakai strain was detected at every sampling location. Two strains of Escherichia coli O157 carrying the stx2 gene were independently isolated from sediment. These results show that river sediment is a potential reservoir of the stx2 gene and Shiga toxin-producing bacteria in the natural environment.