title: Antimalarial drug sensitivity profile of western Kenya Plasmodium falciparum field isolates determined by a SYBR Green I in vitro assay and molecular analysis.
abstract: In vitro drug sensitivity and molecular analyses of Plasmodium falciparum track drug resistance. DNA-binding fluorescent dyes like SYBR Green I may allow field laboratories, proximal to P. falciparum collection sites, to conduct drug assays. In 2007-2008, we assayed 121 P. falciparum field isolates from western Kenya for 50% inhibitory concentrations (IC(50)) against 6 antimalarial drugs using a SYBR Green I in vitro assay: 91 immediate ex vivo (IEV) and 30 culture-adapted, along with P. falciparum reference clones D6 (chloroquine [CQ] sensitive) and W2 (CQ resistant). We also assessed P. falciparum mdr1 (Pfmdr1) copy number and single nucleotide polymorphisms (SNPs) at four codons. The IC(50)s for IEV and culture-adapted P. falciparum isolates were similar, and approximated historical IC(50)s. For Pfmdr1, mean copy number was 1, with SNPs common at codons 86 and 184. The SYBR Green I assay adapted well to our field-based laboratory, for both IEV and culture-adapted P. falciparum, warranting continued use.
authors: Global Emerging Infections Surveillance (GEIS) Program, United States Army Medical Research Unit-Kenya (USAMRU-K), Kenya Medical Research Institute (KEMRI)-Walter Reed Project, Kisumu and Nairobi, Kenya. hakala@wrpksm.org
authors: Hoseah M
authors: HM
authors: Akala
authors: Fredrick L
authors: FL
authors: Eyase
authors: Agnes C
authors: AC
authors: Cheruiyot
authors: Angela A
authors: AA
authors: Omondi
authors: Bernhards R
authors: BR
authors: Ogutu
authors: Norman C
authors: NC
authors: Waters
authors: Jacob D
authors: JD
authors: Johnson
authors: Mark E
authors: ME
authors: Polhemus
authors: David C
authors: DC
authors: Schnabel
authors: Douglas S
authors: DS
authors: Walsh
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007630:Kenya; D010963:Plasmodium falciparum / Q000187:drug effects*
chemical_list: D000962:Antimalarials