FIG. 1.

Trophozoites and early schizonts are most susceptible to the delayed action of antibiotics. P. falciparum 3D7 parasites were cultured in the presence of antibiotics at twice the IC₅₀ at 96 h (100 nM azithromycin [AZ], 6 μM ciprofloxacin [CIP], 25 nM clindamycin [CLN], and 1 μM doxycycline [DOX]), except that rifampin-treated parasites were dosed at twice the IC₅₀ at 48 h (6 μM rifampin [RIF]). The portions of the life cycle during which parasites were treated are indicated by dark shading. New rings were counted 96 h (AZ, CIP, CLN, and DOX) or 48 h (RIF) after the initiation of treatment. Percentages of control parasitemias are shown.