Tritrichomonas foetus: Stable anaerobic resistance to metronidazole in vitro

摘要: Abstract Stable anaerobic resistance of Tritrichomonas foetus to metronidazole was induced in vitro by cultivation trichomonads the Diamond's TYM medium with concentrations sublethal parasites. Nine metronidazole-resistant strains were derived from four drug-susceptible clones T. strain KV-1. Subculturing parasites at both increasing and constant pressure drug resulted development if contained least 3 μg ml−1 organisms exposed for 8 months. The gradual all investigated proceeded through similar sequence stages: (1) Survival without growth subsequent reproduction low (1 5 ml−1. (2) moderate (10 15 (3) Resistance 100 metronidazole, unstable absence selective drug. (4) high stable when maintained under nonselective conditions. fully developed able grow culture could be indefinitely these minimal lethal obtained an assay were, 48 h, 500 1000 This is 400 times higher than those parent clones. over 2 years. substrains regained susceptibility after 80 transfers drug-free media. These strains, however, retained their doses full restored subculture presence 10 μ metronidazole.