ABSTRACT
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.
Subject(s)
Antigens, Bacterial/genetics , Bacterial Outer Membrane Proteins/genetics , DNA, Bacterial/genetics , Escherichia coli Infections/microbiology , Escherichia coli/genetics , Feces/microbiology , Fimbriae, Bacterial , Genes, Bacterial , Urinary Tract Infections/microbiology , Acute Disease , Adhesins, Escherichia coli , Adolescent , Agglutination Tests , Bacterial Adhesion , Bacteriuria/microbiology , Carbohydrate Sequence , Child , Cystitis/microbiology , DNA Probes , Escherichia coli/isolation & purification , Female , Humans , Infant , Molecular Sequence Data , Nucleic Acid Hybridization , Pyelonephritis/microbiologyABSTRACT
The development of renal scarring was analyzed prospectively in 241 boys with their first known episode of symptomatic urinary tract infection (140 acute pyelonephritis, 61 acute cystitis, and 40 nonspecific). Of 197 boys undergoing urography, 22 (11%) had scars; 20 were in the pyelonephritis group. Vesicoureteral reflux occurred in 81% of those with scarring, compared with 20% of those without scarring. The bacteria causing the first episode of urinary tract infection in each patient were saved, and Escherichia coli organisms were characterized for the expression of both galactose-alpha (1----4)galactose-beta (Gal-Gal)-specific adhesins and pap homologous DNA. Scarring occurred in 41% and other renal abnormalities in 11% of boys infected with bacteria that did not bind Gal-Gal (Gal-Gal negative), compared with 5% and 1%, respectively, in those infected with Gal-Gal-binding strains (Gal-Gal-positive) (relative risk 8.3; 95% confidence limits 3.3 to 20.4; p less than 0.001). That boys infected with Gal-Gal-negative strains more often had reflux did not explain the increased risk for renal scarring in this group. The possibility that the phenotypically negative strains could be induced to express Gal-Gal adhesions in vivo was excluded by dot blot analysis, which showed the absence of pap homologous DNA in all but one of the Gal-Gal-negative strains. The results suggest that the absence of Gal-Gal-specific adhesins in E. coli can be used as an indicator of risk for renal scarring and the need for radiologic examination.
