Detection of Plasmodium falciparum K13 Propeller A569G Mutation after Artesunate-amodiaquine Treatment Failure in Niger

Background: Artemisinin (ART) resistance is a problem that may compromise the elimination of
malaria. It is associated with point mutations in the kelch gene PF3D7_1343700 or K13 propeller
(pfk13). A recent worldwide map of pfk13 polymorphisms revealed more than 100 non-synonymous
(NS) mutations. However, it remains unclear whether these mutations are the result of drug pressure
or the expression of a natural polymorphism, because of the scarcity of in-vivo selection of pfK13
mutations data in Africa.
Methodology: This survey evaluates the association between mutations in PfK13 and the response
to treatment with artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ) at Gaya, Niger.
Mutations in PfK13 before and after treatment were analyzed and used as evidence for the selection
of drug resistance following drug pressure.
Results: A total of 161 DNA from patients included in a therapeutic efficacy survey comparing AL vs
ASAQ at Gaya sentinel site in 2011 were amplified and sequenced. Five SNPs were identified
including 3 non-synonymous (NS) mutations (R528K, A569G and V637I) and 2 synonymous (SY)
mutations (C469C and Q613Q). Four SNPs were observed prior to artemisinin-based Combination
Therapy (ACT) including 2 NS (R528K and V637I) and 2 SY (C469C and Q613Q) mutations. One NS
mutation was selected by ASAQ (PfK13A569G) whereas AL treatment did not select any mutation.
Conclusion: This study suggests that the mutation pfk13A569G is selected by ASAQ. Further
mutagenesis studies (CRISPR/Cas9 or Z-Finger Nuclease) will be needed to confirm if pfk13A569G
confers resistance to artemisinin.