Subtyped eae-genes in Shigatoxin-produced Escherichia coli (STEC) - Occurence in raw or undercooked food samples and comparison of isolates from faecal samples and stool samples

We subtyped eae-genes in 19 isolates from raw or undercooked samples (milk, meat, sausage, cheese) by using PCR. Furthermore we investigated 17 isolat es from faecal samples from cattle and 30 isolates from stool samples from HUS-and enteritis patients and from carriers without symptoms for compariso n. We detected the gamma-eae type first and foremost in 20 isolates belongi ng to serogroups O157:H7 or O157:H-.In addition it was found in 5 strains b elonging to serogroup O145 and in 1 isolate of serogroup O111. beta-eae was detected in 7 isolates belonging to serogroup O26 and in 2 strains of sero groups O118 and O5. It was impossible to estimate the serogroup of 6 other isolates containing the beta-type. alpha-eae was detected in 5 isolates of different serogroups but the epsilon-type was found in 10 isolates belongin g to serogroup O103:H2. It was impossible to detect differences in occurren ce of eae-types between isolates from foods, faeces or stool samples. Furth ermore we used different PCR systems for investigation of the insertion of locus of enterocyte effacement (LEE) in sel C. We detected that a LEE, cont aining the epsilon-eae is not integrated in sel C. But a LEE with the alpha -eae disruptes the sel C. All isolates containing the gamma-type showed onl y a positive PCR result by using primer pair K295/K296 indicating an insert ion in sel C. But PCR results by using primer pair K255/K260 were negative. All beta-eae containing strains showed no PCR signal independent of the pr imer types. Further investigations by using DNA-Sequencing are necessary fo r detection of other LEE-insertion loci like phe U.