ISOLATES OF ESCHERICHIA-COLI 044 H18 OF DIVERSE ORIGIN ARE ENTEROAGGREGATIVE/

One hundred thirteen strains of Escherichia coli O44:H18 isolated in s everal countries over 25 years were examined for adhesion to tissue cu lture cells and for hybridization with DNA probes. Fifty-nine strains were from sporadic cases of infection; 54 were from 12 outbreaks. Of t he 113 strains, 85 showed aggregative adhesion to HEp-2 cells; 36 were from sporadic cases and 49 were from 9 outbreaks. All adhesive strain s hybridized with the probe for enteroaggregative E. coli (EAggEC) and 1 nonadhesive strain was also positive. However, 80 of the 86 EAggEC probe-positive strains also hybridized with the probe for diffusely ad herent E. coli (DAEC) derived from the daaC gene of strain F1845. The EAggEC and DAEC probes hybridized to different fragments of a large pl asmid in the O44:H18 strains.