RFLP Southern blot analysis of SD isolates. (A) cpe RFLP Southern blot analysis of NruI-digested DNAs from SD isolates with a 639-bp DIG-labeled cpe-specific probe. Results are shown for control strains NCTC8239 (a chromosomal cpe, food poisoning isolate), F4969 (a plasmid cpe, non-food-borne GI disease isolate), and ATCC 3624 (a cpe-negative isolate) and for representative SD isolates 6253/94, 6257/94, 6263/95, and 7458/94. Molecular sizes of the hybridizing DNA fragments are given to the left. (B) cpb2 RFLP Southern blot analysis of HpaI-digested DNAs from SD isolates with a 318-bp DIG-labeled cpb2-specific probe. Results are shown for control isolates CWC245 (a cpb2-positive, pig GI disease isolate) and 106527 (a cpb2-negative isolate) and for representative SD isolates 6253/94, 6257/94, 3433/95, and 4178/94. Molecular sizes of the hybridizing DNA fragments are given to the left.