title: In vitro monitoring of Plasmodium falciparum susceptibility to artesunate, mefloquine, quinine and chloroquine in Cambodia: 2001-2002.
abstract: We used a classical isotopic microtest to assess the in vitro sensitivity of 352 Plasmodium falciparum isolates collected in Cambodia in 2001 and 2002 to chloroquine, mefloquine, quinine and artesunate. Our results confirm conclusions drawn from earlier studies conducted by the Cambodian national malaria centre. Chloroquine-resistant phenotypes were highly prevalent in Cambodia. Similarly, a high proportion of isolates displayed elevated IC50 to mefloquine. In contrast, only 0.67 and 1.7% of isolates presented decreased susceptibility to quinine and artesunate, respectively. Distributions of mean IC50 according to drug and geographic origin indicated that the parasites circulating to the west of Cambodia largely account for the global situation of drug resistances in Cambodia. Isolates with decreased susceptibility to chloroquine and mefloquine were common along the border with Thailand. In contrast, most of the isolates from eastern Cambodia were susceptible to these compounds. Isolates collected at the western and eastern borders did not respond differently to artesunate. No major differences in responses to antimalarial drugs were observed between 2001 and 2002, suggesting that the situation of drug resistance is now stabilized and under control in Cambodia. However, the decreased susceptibility of isolates collected in the western provinces of Cambodia to mefloquine and the correlation between susceptibility to artesunate and susceptibility to mefloquine and quinine justify the need for an improved international surveillance program for malaria drug resistance in the Mekong sub region.
authors.affiliation: Laboratoire d'Epidémiologie Moléculaire, Institut Pasteur du Cambodge, #5 bd Monivong, P.O. Box 983, Phnom Penh, Cambodia.
authors.forename: Pharath
authors.initials: P
authors.lastname: Lim
authors.forename: Pheaktra
authors.initials: P
authors.lastname: Chim
authors.forename: Rithy
authors.initials: R
authors.lastname: Sem
authors.forename: Sina
authors.initials: S
authors.lastname: Nemh
authors.forename: Yi
authors.initials: Y
authors.lastname: Poravuth
authors.forename: Chiv
authors.initials: C
authors.lastname: Lim
authors.forename: Soun
authors.initials: S
authors.lastname: Seila
authors.forename: Reiko
authors.initials: R
authors.lastname: Tsuyuoka
authors.forename: Mey Bouth
authors.initials: MB
authors.lastname: Denis
authors.forename: Doung
authors.initials: D
authors.lastname: Socheat
authors.forename: Thierry
authors.initials: T
authors.lastname: Fandeur
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D037621:Artemisinins / Q000494:pharmacology; D000077332:Artesunate; D002160:Cambodia; D002738:Chloroquine / Q000494:pharmacology; D004351:Drug Resistance; D006801:Humans; D020128:Inhibitory Concentration 50; D016778:Malaria, Falciparum / Q000469:parasitology; D015767:Mefloquine / Q000494:pharmacology; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000302:isolation & purification; D011803:Quinine / Q000494:pharmacology; D012717:Sesquiterpenes / Q000494:pharmacology; D018709:Statistics, Nonparametric
chemical_list: D000962:Antimalarials; D037621:Artemisinins; D012717:Sesquiterpenes; D000077332:Artesunate; D002738:Chloroquine; D011803:Quinine; D015767:Mefloquine