Chloroquine Resistance Transporter (Pfcrt) and Multidrug Resistance 1 (Pfmdr1) Genes Mutation in Plasmodium Falciparum Population Under Varying Level of Endemicity with Plasmodium Vivax in Selected Parts of Ethiopia
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Date
2023-02
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Addis Ababa University
Abstract
The global controlling of Plasmodium falciparum infections faces significant challenges due to the spread of parasites resistant to antimalarial drugs. In Ethiopia, where both P. vivax and P. falciparum coexist, the treatment for uncomplicated falciparum malaria shifted from chloroquine (CQ) to sulfadoxine-pyrimethamine (SP) in 1998 and then to Coartem (artemether-lumefantrine (AL)) in 2004. AL has been the standard treatment for over two decades for P. falciparum, while P. vivax is still treated with CQ. The coexistence of these two species and the accessibility of CQ for P. vivax treatment raise questions about whether switching from CQ to AL for P. falciparum treatment might lead to the resurgence of CQ -susceptible P. falciparum strains due to reversal mutations or the efficacy of AL. The sudy aimed to assess the prevalence of pfcrt-76 and pfmdr1-86 gene mutations in the P. falciparum population under varying levels of endemicity with P. vivax in selected parts of Ethiopia. In this study the frequency of gene mutations of P. falciparum chloroquine resistance transporter 76 (pfcrt-76) and P. falciparum multidrug resistance 1-86 (pfmdr1-86) in P. falciparum collected from malaria-infected patients in Abobo, Dera, Fentale, and Metema districts, Ethiopia, were examined. Confirmed P. falciparum samples (n = 258) with microscope were collected through health facility-targeted cross-sectional surveys in areas with varying levels of P. falciparum and P.vivax prevalence. Genomic DNA was extracted from dried blood spots by using MagMAX DNA Multi-Sample Kit, operated by the Kingfisher Flex Automated Extractor. An 18S rRNA gene-based multiplex real-time PCR assay was employed to confirm P. falciparum mono-infection samples (n = 258). The study analyzed 258 P. falciparum-infected patients using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), examining Pfmdr1-86 and Pfcrt-76 gene mutations. Fisher's exact test determined marker distribution significance. Out of 250 genotyped for Pfcrt K76T, 68.8% had mutant 76T, and 31.2% were wild-type K76. For 257 genotyped for Pfmdr1-N86Y, 98.44% was N86 wild-type, and 1.56% was 86Y mutants. The mutant Pfcrt-76T was more prevalent in areas with higher P. vivax endemicity, including 93.33% (Fentale), 84.71% (Dera), 57.5% (Metema), and 43.75% (Abobo). Pfcrt-76 gene single nucleotide polymorphisms (SNPs) significantly correlated with P. vivax endemicity (P = 0.000). Pfmdr1-N86 was predominantly 100% except in Abobo, where 95.18% were N86, and 4.81% were 86Y. Pfmdr1 gene SNPs were significantly associated with P. vivax endemicity (P = 0.025). Despite CQ discontinuation for over two decades in Ethiopia, a substantial proportion of P. falciparum isolates still carry mutant 76T genotypes, indicating latent CQ pressure. The use of AL for uncomplicated P. falciparum malaria may lead to the return of Pfmdr1 N86 wild-type genes. Further molecular epidemiological investigations in varied endemic regions with different CQ usage histories are recommended to understand chloroquine (CQ) susceptibility recovery and AL therapy efficacy.
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Plasmodium Falciparum, Drug Resistance, Pfcrt K76t, Pfmdr1-N86y, Artemether-Lumefantrine, Chloroquine Resistance, Chloroquine Sensitive, Ethiopia