Cloning and Characterization of Mefloquine-Resistant Plasmodium falciparum from Thailand

摘要

Resistance to mefloquine in Plasmodium falciparum has begun to occur along the border of Thailand and kampuchea. As a means of assessing the natural occurance of mefloquine resistance, the admission and post-treatment parasite isolates from a mefloquine treatment failure were cloned and characterized. Clones from the admission isolate were susceptable to mefloquine in vitro (ID50 of 3.4 (2-5), G (95% CI) ng/ml) and showd a mixure of isozyme types for glucose phosphate isomerase (GPI types I and II). The post treatment clones were resistant to mefloquine in vitro (ID50 of 17.3 (13-23) ng/ml) with only one isozyme (GPI-I) detected these observations suggest that under mefloquine pressure a resistance parasite population was selected in the patient, indicating the potential for mefloquine resistance already exists in the indigenous P. falciparum gene pool. In addition the mefloquine-resistant clones showed decreased susceptibility in vitro to halofantrine suggesting possible cross resistance to this new antimalarial drug currently under development.