Comparison of two in vitro sensitivity tests for Plasmodium falciparum
Chaijaroenkul, W.; Tippawangkosol, P.; Kuesap, J.; Congpuong, K.; Ruenweerayut, R.; Suwandittakul, N.; Songthammawat, D.; Na-Bangchang, K.
Southeast Asian Journal of Tropical Medicine and Public Health 37(1): 5-12
2006
ISSN/ISBN: 0125-1562 PMID: 16771205 Document Number: 604336
The main purpose of the study was to compare the in vitro sensitivity results obtained from the two widely-used in vitro systems: (1) standard WHO micro-technique based on schizont maturation inhibition using fresh isolates (M-I), and (2) micro-technique based on incorporation of [3H]-hypoxanthine using culture-adapted isolates (M-II). The study was conducted during 1998 and 2002. A total of 473 Plasmodium falciparum isolates were collected from five highly malaria endemic areas of Thailand, ie, Mae Sot district, Tak (north-western), Kanchanaburi (western), Ranong (south-western), Ratchaburi (south-western) and Chantaburi (eastern) Provinces. The antimalarials tested were: mefloquine, quinine, chloroquine, artemisinin and dihydroartemisinin. The sensitivity results for mefloquine obtained from the two methods were significantly different from each other. The IC50 values for M-II was less than M-I. The median (95%C.I.) IC50 value for mefloquine using the M-II method was significantly lower (696.47 (393.11-1233.2) nM) than for M-I (3955.4 (1035.61-5108.9) nM). The in vitro sensitivity results for quinine were significantly different from each other. The median (95% C.I.) IC50 value for M-II (161 (42-351) nM) was 2.5-fold that of M-I (66 (24-450) nM).