Thin Aggregative Fimbriae on Urinary Escherichia coli Isolates
In the present work we investigated the occurrence of curli (thin aggregative fimbriae)on E. coli strains isolated from urinary tract infections with significant bacteriurea. In our collection of fresh isolates more than 50 % of the strains expressed surface structures morphologically indistinguishable from curli. ELISA reaction with anti-serum to the analogous thin aggregative fimbriae of S. enteritidis revealed a strong antigenic relationship between curli fimbriae of representatives of these two different bacterial genera. While 29 E. coli strains were positive ba electronmicroscopy,only 26 of them presented with positive result in the ELISA reaction. It needs further analysis if some of the E. coli strains may express thin aggregative fimbriae antigenically entirely distinct from that of S. enteritidis. Another possibility is that our criteria for ELISA positivitiy were too strict.
Expression of thin aggregative fimbriae of urinary E. coli isolates is in most cases under thermoregulatory control with an expression preference at ambient temperature. Considering the fact that curli is rarely present at body temperature it is not clear if any pathogenetic role could be attributable to it. One can speculate that aggregative bacterial surface structures with an expression preference at 30–32ºC might be involved in primary colonisation of external surfaces like the perineal region and the orificium of the urinary tract.
KeywordsExpression Preference Coli Isolate Perineal Region Primary Colonisation Fresh Isolate
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