PA-452 Molecular surveillance for polymorphisms associated with artemisinin-based combination therapy resistance in plasmodium falciparum isolates from southern Brazzaville and beyond in the Republic of Congo

BackgroundEmergence and spread of P.falciparum strains resistant to artemisinin-based combination therapies (ACTs), poses a significant threat to global malaria control efforts. Therefore, the close monitoring of molecular markers is essential as an early warning system to detect the emergence and spread of resistance. This study aims to assess the prevalence of haplotypes of the Pfcrt, Pfmdr1 and PfK13 resistance markers in isolates from the south of Brazzaville and beyond, in the Republic of Congo. MethodsBetween March and October 2021, a cross-sectional study was conducted in rural and urban areas of the south of Brazzaville and beyond in individuals aged 1–83 years with microscopic P. falciparum infection. Parasite DNA was extracted using Qiagen kit and all samples were screened to confirm P. falciparum infection by nested PCR. Restriction Fragment Length Polymorphism was used for the detection of single nucleotide mutation within the Pfcrt, Pfmdr1 genes of the parasite, and detected mutations were further confirmed using Oxford nanopore sequencing platform, while PfK13 gene mutations were investigated by sequencing. ResultsAmong 329 samples with confirmed P. falciparum infection, the overall prevalence of the 76T (Pfcrt), 86Y (Pfmdr1) and 184F (Pfmdr1) mutations were 26.7%, 5.3% and 23.9% respectively. The Pfk13 wild type was found in 98.3% isolates while, 1.7% isolates had a mutation in the Pfk13 domain (4 synonymous mutations and 1 non-synonymous mutation, A578S). No significant difference was observed between rural and urban data.ConclusionThese results indicate low prevalence of mutations within the Pfcrt, Pfmdr1 genes of P. falciparum and no validated Pfk13 mutation associated with artemisinin drug resistance in this study setting, suggesting that ACTs remain effective in the area, but required continuous surveillance.