BACKGROUND P fimbria is one of the main factors of virulence of the uropathogenic Escherichia coli strains thus developing methods for its detection is of interest. P fimbriation may manifest through associated characteristic hemagglutination patterns. Another way of directly detecting its expression is by the PF test consisting in a specific agglutination test with latex particles which have the specific receptor of the fimbria incorporated. METHODS The two phenotypic techniques (hemagglutination pattern using human, bovine, and sheep erythrocytes, and the PF test) were compared with colony hybridization with a specific DNA probe (pap1) in 35 strains of uropathogenic E. coli. RESULTS Eight of the 35 strains studied were positive for the PF test with 7 strains presenting mannose-resistant agglutination to human erythrocytes without agglutinating the other erythrocytes tried. However, with hybridization with the DNA probe the number of positives was higher (25/35). CONCLUSIONS The difference found in the number of positive strains may be due to the probe used corresponding to cluster pap, thus the use of a smaller more specific probe for fimbrial expression obtained from pap should be used given that the hybridization technique is easy to perform and is carried out in less time than phenotypic detection which requires long periods of culture prior to the test.