ABSTRACT
A simple in vitro drug sensitivity testing system for Blastocystis hominis clinical isolates was developed. Application of supravital staining by neutral red allowed quantitative viability assessment. Four xenic cultures, isolated from human sources, were grown in modified monophasic Robinson's medium and tested for sensitivities to nine available drugs. Assessment was done using the cell-count method from air-dried preparations after supravital staining with neutral red. Also, the light absorbence method was evaluated. Trimethoprim, metronidazole, quinacrine, tetracycline, paromomycin, and two new antiprotozoal drugs, nitazoxanide and deacetyl-nitazoxanide, showed cytostatic or cytocidal effects on all or some Blastocystis isolates. Chloroquine and sulphamethoxazole did not demonstrate any effect at the concentrations studied.
Subject(s)
Amebicides/pharmacology , Blastocystis hominis/drug effects , Coloring Agents , Neutral Red , Animals , Blastocystis hominis/growth & development , Chloroquine/pharmacology , Humans , Metronidazole/pharmacology , Nitro Compounds , Parasitic Sensitivity Tests/methods , Paromomycin/pharmacology , Quinacrine/pharmacology , Staining and Labeling/methods , Sulfamethoxazole/pharmacology , Tetracycline/pharmacology , Thiazoles/pharmacology , Trimethoprim/pharmacologyABSTRACT
Using supravital neutral red staining and light microscopy, individual Blastocystis organisms, subcultured from clinical isolates in modified monophasic Robinson's medium, were followed over various periods on glass slides. A rapid transition from uniformly stained to granular and vacuolated forms preceded the organism's death as evidenced by pale staining and Brownian motion in the cell's interior. Granular and vacuolar forms of Blastocystis may indicate degenerative changes in individual cells, fixation artifact, or both.