The effect of tinidazole on several ciliates.

The effect of tinidazole on several ciliates (Stylonychia muscorum, Stylonychia mytilus, Tetrahymena pyriformis, Vorticella companula) has been studied. There is a very pronounced difference in sensitivity against this drug between the free-living ciliates here investigated and certain parasitic protozoa. A high resistance of the free-living ciliates against tinidazole, probably due to their aerobic condition, has been found. Nonetheless, tinidazole at high doses (1--3 mg/ml) caused severe alterations in 3 of the 4 aerobic ciliate species here studied.