Rapid and specific detection of three different G adhesin classes of P-fimbriae in uropathogenic Escherichia coli by polymerase chain reaction

Uropathogenicity of Escherichia coli has a strong association with P fimbriae. At the tip of P fimbriae are located G adhesins which mediate binding to glycolipid receptors. The G adhesins are encoded by pap or prs gene clusters. The three receptor binding variants of G adhesins (Classes I to III) recognized so far, differ in their binding to different isoreceptors of the Gal alpha 1 - 4gal-containing glycolipid family. Lately, the genetic detection of G adhesins by colony hybridization or polymerase chain reaction (PCR) has been used as an alternative to previous phenotypic P fimbria detection methods. In the present study, 257 E. coli urine isolates from clinically properly characterized patients with either acute cystitis or recurrent E. coli infections were examined for the three G adhesin classes with a PCR-based method. The PCR reaction was carried out with four oligonucleotide primers in a single reaction tube. Sixty-five isolates (25%) had genes for Class II G adhesin, 31 (12%) for Class III and two additional isolates had genes for both Class II and III G adhesins. Of the total of 98 strains possessing genes for P fimbriae, 26 (27%) were undetectable with the previous P-specific latex agglutination test and 7 (7%) strains with the mannose-resistant heme agglutination method. The new PCR method presented in this study allows an easy, fast, cheap, sensitive and reliable detection method for P fimbriae as well as the specific G adhesin type. Thus, it allows further evaluation of the clinical significance of these G adhesins in strains causing other types of urinary tract infections (UTI) other than cystitis. (C) 1998 Elsevier Science B.V. All rights reserved.