A survey of pathogenic genes from diarrhea stool samples obtained in Nara prefecture.

We conducted a survey of diarrhea stool samples in which no virulent agents had previously been detected at clinical laboratories. DNA extracted directly and purified from the diarrhea stool was tested for bacterial pathogenic genes by polymerase chain reaction. The test results for 85 specimens were as follows: one sample was positive for lt, ipaH, and eae; two were positive for aggR; and eight were positive for astA. Inoculation with the stool specimens led to the isolation of a strain of Escherichia coli possessing eae, three strains of E. coli possessing astA, and a strain of Klebsiella possessing astA.