Decreased predominance of papG class II allele in Escherichia coli strainsisolated from adults with acute pyelonephritis and urinary tract abnormalities

Purpose: We compared the genotypes of fimbriae or adhesions of Escherichia coli causing acute pyelonephritis in adults with and without urinary tract abnormalities. Materials and Methods: We studied a total of 92 E. coli strains isolated fr om 54 patients with acute pyelonephritis and a normal urinary tract, and 38 with urinary tract abnormalities. Of those with urinary tract abnormalitie s 13 with moderate to severe hydronephrosis were also considered a separate group for the purpose of analysis. The genes of 7 known fimbriae or adhesi ns of E. coli were detected by the polymerase chain reaction, including the papG class I to III alleles (PapG adhesins of P-fimbriae), sfa/foc (S-/F1C -fimbriae), fimH (type 1 fimbriae), and afa (afimbrial adhesin). Virulence genes associated with APN were identified by comparing the prevalence of ea ch of these 7 genes in E. coli strains from 54 patients with acute pyelonep hritis with a normal urinary tract to the prevalence in the strains from 37 patients with acute cystitis using univariate and multivariate analysis. D ifferences in the prevalence of the genes associated with acute pyelonephri tis and the incidence of underlying illness were then compared in the 3 acu te pyelonephritis groups. Results: On univariate and multivariate analysis the papG class II allele w as the only virulence gene associated with acute pyelonephritis (p < 0.0001 and 0.001, respectively). No significant difference was noted in the preva lence of underlying medical disease in the 3 acute pyelonephritis groups. T he papG class II allele was significantly less predominant in E. coli strai ns isolated from acute pyelonephritis cases with versus without urinary tra ct abnormalities (76% versus 93%, p = 0.03). The incidence of the papG clas s II allele in patients with urinary tract abnormalities and moderate to se vere hydronephrosis was less than in those without urinary tract abnormalit ies (69% versus 93%, p = 0.04). Conclusions: Our results imply that the papG class II allele has an importa nt role in E. coli infection in patients with acute pyelonephritis and a no rmal urinary tract, while urinary tract abnormalities and/or obstruction ma y permit ascending infection of E. coli strains with lower adhesive ability .