Special virulence of the Escherichia coli O1:K1:H7 clone in acute pyelonephritis.

The relationship between acute-phase responses and bacterial properties was studied in a population of 88 children with their first known episode of acute pyelonephritis. One strain from each patient was included in the study. Eighty-four of the patients were infected with Escherichia coli, which was assigned a clonotype according to the O:K:H stereotype; 55 patients carried one of the 12 multiply occurring clones. Globotetraosylceramide-specific (globo+) adhesion was present in 90% of these 12 clones, compared with 62% in the remaining 29 singly occurring clones. The patients infected with globo+ strains had significantly increased inflammatory reactions compared with patients with globo- strains. The O1:K1:H7 strain was the single most frequent clone (n = 14) that always expressed globo+ adhesins. Patients infected with O1:K1:H7 had an inflammatory response similar to that of other globo+ infections, but had a shorter duration of symptoms before diagnosis, higher fever, and higher peripheral leukocyte count. These results demonstrate special virulence of the O1:K1:H7 clone, reflected by the acuteness of onset of infection.