Efecto del herbicida ácido 2,4-diclorofenoxiacético sobre la fimbriación de bacterias uropatógenas

epidemiological data demonstrate, on rural populations, that the frequency of inflammatory lesions in renal tissue is higher for individuals exposed to pesticides. previous studies demonstrated that the herbicide 2,4-d altered the bacterial adherence properties to renal tissue, mediated by fimbriae in uropathogenic escherichia coli, but the mechanism involved is still unknown. the acid 2,4- d has the ability to perform covalent bonds to proteins in gram-negative bacteria. because of this fact, we hypothesized that the 2,4-d acid binds proteins involved in the synthesis, export or ensemble of fimbrial subunits, modifying fimbrial expression. in this work we demonstrated a covalent bond of the herbicide to outer membrane proteins in uropathogenic e. coli and a parallel decrease of fimbriation, assayed by three different methods: hemmaglutination, surface protein quantification and electron microscopy. an important conclusion is that the accidental exposure of rural workers to 2,4-d may have a protective effect by a decrease in fimbriation, when it is used in low doses and during a short period of exposure. but, it must be considered that high doses and several days of exposure had adverse effects, like recurrence of infection, in the mouse model of ascending pyelonephritis (balagué et al, 2002). probably, the epidemiological studies that associate the herbicide exposure with renal infection were due to the last kind of exposure described.