International journal for parasitology. Drugs and drug resistance

Temporal trends in prevalence of Plasmodium falciparum drug resistance alleles over two decades of changing antimalarial policy in coastal Kenya.

PMID 25516825


Molecular surveillance of drug resistance markers through time provides crucial information on genomic adaptations, especially in parasite populations exposed to changing drug pressures. To assess temporal trends of established genotypes associated with tolerance to clinically important antimalarials used in Kenya over the last two decades, we sequenced a region of the pfcrt locus encompassing codons 72-76 of the Plasmodium falciparum chloroquine resistance transporter, full-length pfmdr1 - encoding multi-drug resistance protein, P-glycoprotein homolog (Pgh1) and pfdhfr encoding dihydrofolate reductase, in 485 archived Plasmodium falciparum positive blood samples collected in coastal Kenya at four different time points between 1995 and 2013. Microsatellite loci were also analyzed to compare the genetic backgrounds of parasite populations circulating before and after the withdrawal of chloroquine and sulfadoxine/pyrimethamine. Our results reveal a significant increase in the prevalence of the pfcrt K76 wild-type allele between 1995 and 2013 from 38% to 81.7% (pxa0