A simple reliable agglutination test for screening P-fimbriated Escherichia coli in children with urinary tract infections gives valuable clinical information.

Most urinary tract infections (UTI) are caused by Escherichia coli (E. coli) and the pathogenetic mechanisms of this bacterium have been thoroughly studied. Lipopolysaccharide (LPS), capsular polysaccharides and fimbrial structures are among the more important virulence markers. P-fimbriae, with a specificity for the carbohydrate structure of the P blood group system (alpha-D-Gal-1,4-beta-D-Gal) have attracted particular interest, as non-fimbriated E. coli rarely give rise to pyelonephritis, unless the normal defence mechanisms of the urinary tract are impaired. We have evaluated a commercial test (Orion Diagnostica, PF test), developed to detect P-fimbriae on E. coli from clinical isolates. It is based on latex particles with covalently bound receptors (alpha-D-Gal-1,4-beta-D-gal). In this study a high correlation was found between pyelonephritis, as judged by clinical and biochemical criteria, and a positive PF test.