Profiling antimalarial drug-resistant haplotypes in Pfcrt, Pfmdr1, Pfdhps and Pfdhfr genes in Plasmodium falciparum causing malaria in the Central Region of Ghana: a multicentre cross-sectional study.

Abstract

Background: The proliferation of Plasmodium parasites resistant to antimalarial drugs poses a serious threat to human life and remains an obstacle to managing and eradicating Plasmodium falciparum. The surveillance of molecular markers has become necessary to monitor the spread of resistant haplotypes and discover emerging mutations.

Objective: This molecular epidemiological study aimed to evaluate the prevalence of known mutations in the drug resistance genes Pfcrt, Pfmdr1, Pfdhfr and Pfdhps in the Central Region of Ghana.

Design: A multi-centre cross-sectional study.

Methods: This prospective study utilised dried blood spots from individuals with P. falciparum-infection from five districts in the Central Region of Ghana. Selective Whole Genome Amplification (sWGA) and Single Nucleotide Polymorphisms (SNPs) in P. falciparum chloroquine transporter genes (Pfcrt), P. falciparum multidrug resistance 1 (Pfmdr1), P. falciparum dihydropteroate synthase (Pfdhps) and P. falciparum dihydrofolate reductase (Pfdhfr) were analysed.

Results: Whole genome sequencing was carried out on 522 samples. Of these, 409 (78%) samples were successfully sequenced. Six (6) of the sequenced samples were of co-infection of other parasite species with P. falciparum and excluded from the analysis. Analysis of the Pfcrt gene revealed 0.5% were CVIET (C72, V73, M74I, N75E, K76T) while the Pfcrt CVMNK (C72, V73, M74, N75, K76) wild-type haplotypes were 97% with (2.5%) (CV[M/I][N/E][K/T]) being mixed haplotypes. In the Pfmdr1 gene, monoclonal haplotypes; NFD (N86, Y184F, D1246) and YFN (N86Y, Y184F, D1246N) occurred at 44% and 9.8%, respectively, whereas mixed- haplotypes (N[Y/F]D and [N/Y][Y/F]D) were 23.5% and 0.3%, respectively. Combined Pfdhfr/Pfdhps genes yielded about 88% Pfdhfr IRNI (N51I, C59R, S108N, I164) + Pfdhps A437G haplotypes (conferring partial resistance to Sulphadoxine-Pyrimethamine (SP)) while 9% of the parasites had Pfhdfr IRNI + Pfdhps A437G + K540E haplotypes (conferring full resistance to SP). The wild-type haplotype, Pfdhfr (N51, C59, S108, I164) and Pfdhps (S436, A437, K540, A581, A613) was not observed.

Conclusion: The findings show a low prevalence of CVIET and relatively higher rates for Pfmdr1 NFD and parasites with Pfdhfr IRNI (N51I, C59R, S108N, I164) + Pfdhps A437G haplotypes. These observations advocate for enhanced surveillance which is inimical to malaria management in an endemic area.