Summary: Sequences encoding the production of a cytotoxin (VT) active on Vero cells were cloned in K12 from a VT-determining phage that originated in strain H19 of serotype O26. H11. Subcloning resulted in the identification of a 2·5 kb fragment that still coded for VT production. Mutagenesis with transposon Tn was used to map VT sequences and a 0·75 kb probe was developed. In colony hybridization tests with strains isolated from patients with haemolytic uraemic syndrome or diarrhoea, this probe derived from the H19 VT genes detected only some of the VT strains belonging to serogroup O157. A VT strain, E32511, serotype O157. H, which was negative in colony hybridization was the source of another VT-determining phage from which VT sequences were cloned. Southern hybridization of the VT genes from E32511 with the H19 probe was negative under stringent conditions but there was weak homology under conditions of low stringency. These results indicate that there are differences in the VT genes of pathogenic .


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error