OCCURRENCE OF S-RELATED AND F1C S-RELATED FIMBRIAL DETERMINANTS AND THEIR EXPRESSION IN ESCHERICHIA-COLI STRAINS ISOLATED FROM EXTRAINTESTINAL INFECTIONS/

The presence of S and F1C/S-related fimbrial determinants was determin ed in 462 E. coli strains obtained from different extraintestinal infe ctions and in 162 control isolates of E. coli by using two different D NA probes: an oligonucleotide probe consisting of three oligonucleotid es that bind specifically to the S adhesin gene and a polynucleotide p robe which is not able to distinguish between S; F1C, and S-related se quences. The expression of S and F1C phenotypes was tested by dot enzy me immunoassay with the corresponding monoclonal antibodies. S fimbria e genotypes were observed more frequently in septic (25%) and urinary (12%) isolates of E. coli than in faecal and water isolates (1%) and o ften occurred together with O2, O6, O18 and O83 antigens. F1C/S-relate d fimbrial DNA was detected with a higher frequency in UTI isolates (2 6%) than in septic (16%) and faecal (10%) isolates and was most freque ntly associated with O4, O6, and O75 serotypes. Since the production o f S and F1C fimbriae was comparatively rare in all clinical and contro l isolates of E. coli, DNA hybridization assays which allow the sensit ive and specific detection of fimbrial determinants even in the absenc e of their expression are preferable to phenotypic assays.