BACTERIAL MUTAGENS IN THE URINE OF PATIENTS UNDER TINIDAZOLE TREATMENT

Tinidazole is an antiparasitic drug belonging to the 5-nitroimidazole family. It is prescribed against protozoal infestations and is widely used in Mexico as well as other underdeveloped countries where infecti ous diseases are the first cause of children mortality. The drug is a direct mutagen in Salmonella typhimurium TA100 strain and the presence of S9 mixture did not modify its mutagenic effect. At low doses no mu tagenicity was detected with strains TA100NR, TA98 or UTH8414 (Uvr(+) derivative of TA100). Urine from four patients under tinidazole treatm ent exhibited a mutagenic activity on strain TA100, greater than the e xpected from the tinidazole concentrations determined by high-performa nce liquid chromatography (HPLC). Components from the urine samples we re separated on thin-layer chromatography (TLC) plates, and their muta genic effects tested by direct application of the Salmonella assay ont o sections of the developed chromatoplate. The R(f) of one component ( 0.62) corresponded to the one obtained for a tinidazole standard and s howed the expected mutagenicity, while a second component with an R(f) = 0.39: exhibited a mutagenic potency slightly greater than the obser ved for tinidazole; however, as in the case of the drug itself, reduct ion of the nitro group was necessary for a mutagenic activity.