The pap gene clusters encode P fimbriae and fimbriae-associated G adhesins. DNA sequence analysis has resolved three G adhesin variants (papGJ96, papGIA2 and prsGJ96) that differ in receptor specificity and therefore in binding to epithelial cells. In this study, DNA probes specific for the pap gene cluster or the papGJ96, papGIA2 and prsGJ96 adhesin sequences were used to examine 74 fecal and 204 urinary Escherichia coli isolates (67 from acute pyelonephritis, 71 from acute cystitis and 66 from asymptomatic bacteriuria). In accordance with previous studies, a higher frequency of pap+ strains was found in the urinary strains (71%) than in the fecal (20%) E. coli isolates. The papGIA2, and prsGJ96 sequences were more frequent among urinary (42% papG+IA2, 23% prsG+J96) than among fecal (18% papG+IA2, 5% prsG+J96) isolates. None of the isolates hybridized with the papGJ96 probe. Pap+ strains accounted for 82% of the pyelonephritis, 69% of the cystitis and 61% of the asymptomatic bacteriuria strains. The papGIA2 genotype dominated in acute pyelonephritis strains (72% papG+IA2, 16% prsG+J96). The prsGJ96 genotype was most frequent in cystitis strains (25% papG+IA2, 37% prsG+J96). The asymptomatic bacteriuria strains formed an intermediate group (30% papG+IA2, 14% prsG+J96). Most of the papG+IA2 strains expressed P fimbriae which agglutinated human erythrocytes, sheep erythrocytes and Gal alpha 1-4Gal beta latex beads. The prsG+J96 strains varied in agglutination of human and sheep erythrocytes and Gal alpha 1-4Gal beta-latex beads. The results demonstrated that the papGIA2 and prsGJ96 adhesin DNA sequences differ in disease association.