In vitro induced anaerobic resistance to metronidazole in Trichomonas vaginalis.
J Eukaryot Microbiol
; 40(3): 262-9, 1993.
Article
in En
| MEDLINE
| ID: mdl-8508165
ABSTRACT
Resistance to metronidazole detectable under anaerobic conditions was induced in two Trichomonas vaginalis strains (TV 10-02 and MRP-2) by cultivation at gradually increasing pressure of the drug (1-100 micrograms/ml) for 12 to 21 months. The resistant derivatives reproduced in anaerobic trypticase-yeast-extract-maltose medium at 100 micrograms/ml metronidazole and showed very high values of minimal lethal concentration for metronidazole in anaerobic in vitro assays (556-1,600 micrograms/ml at 48-h exposure to the drug). Stepwise selection was necessary to develop the resistance in either strain. Attempts to induce resistance by prolonged maintenance of trichomonads with constant, low or moderate drug concentrations (3-10 micrograms/ml) were unsuccessful. Freshly developed resistance to high concentrations of metronidazole was unstable in absence of drug pressure as well as after cryopreservation. Development of stable resistance required further cultivation at 100 micrograms/ml metronidazole. Unstable substrains did not revert to original susceptibility. They retained a moderate level of resistance, being able to grow at 10 micrograms/ml metronidazole. The strains with fully developed resistance had no activity of the hydrogenosomal enzymes pyruvate ferredoxin oxidoreductase and hydrogenase and ceased uptake of [14C]-metronidazole. These findings indicate that the pyruvate oxidizing pathway responsible for metronidazole activation was inactivated and metabolism of the drug stopped.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Oxygen
/
Trichomonas vaginalis
/
Metronidazole
Limits:
Animals
/
Female
/
Humans
Language:
En
Journal:
J Eukaryot Microbiol
Journal subject:
MICROBIOLOGIA
/
PARASITOLOGIA
Year:
1993
Document type:
Article