IN-VITRO ACTIVITY OF TOPOISOMERASE INHIBITORS AGAINST PNEUMOCYSTIS-CARINII

The activity of eight topoisomerase inhibitors was investigated agains t five clinical isolates of Pneumocystis carinii. Susceptibility tests were performed by inoculation of the organisms on to a cell monolayer and parasites were counted after 72 h incubation at 37 degrees C, Cul ture plates were added with Dulbecco's modified Eagle's medium contain ing serial dilutions of lomefloxacin, norfloxacin, ofloxacin, pefloxac in, rufloxacin, camptothecin, amsacrine and etoposide. Atovaquone, pen tamide isethionate and co-trimoxazole were used as control drugs. Etop oside gave inhibition comparable to that observed with atovaquone. Poo r activity was demonstrated by pefloxacin, while the other topoisomera se inhibitors had no significant effect.