The use of short-term cultures of Pneumocystis for drug testing

A method for short-term drug testing for Pneumocystis is described. Up to now there was no successful cultivation method without feederlayers. Parasites for inocula were obtained from nude rats, kept under conventional conditions. Pneumocystis separation was done by two centrifugation steps from lung homogenates. Cultivation in a modified Tegoshi medium resulted in preservation of parasites for five days, however there was no growth of P. carinii. Quantification was done microscopically by counting trophozoites in triplicate cultures. The percentage of cysts with intracystic bodies did not exceed 2% of parasites. Tests with pentamidine isethionate as a reference drug demonstrated the suitability of this system for drug evaluation.