RESUMEN
Objective To understand whether or not artesunate (Art. ) combined with naphtho-quine (Nap. ) can delay the resistance of Plasmodium falciparum to Art. Methods In Group A, P. falciparum was cultured in culture medium and was stimulated by Art/Nap disconnectedly, and in Group B, stimulated by Art disconnectedly. When P. falciparum recovered to normal growth level, the changes of sensitivity (ID50) to the drugs were compared between the two groups after P. falciparum touched on the drug. Results In Group A, the times P. falciparum recovered to normal growth level were 24, 37 d respectively when it contacted the drugs in the first and second times; P. falciparum didn't recover to normal growth level in 90 d when it contacted the drugs in the third time. In Group B, the times P. falciparum recovered to normal growth level were 16. 7 d (15-20) on average. ID50(s) of Art/Nap were 2.42/37.81, 1. 70/26.30 nmol/L before and 65 d after contacting the drugs in Group A; ID50(s) of Art were 9. 60, 30. 61, 85.12 nmol/L before and 68 and 129 d after contacting the drug in Group B. Conclusion Artesunate-resistant P. falciparum can be cultured by touching artesunate at intervals in vitro; Artesunate combined with naph-thoquine may delay the resistance of P. falciparum to artesunate in vitro.