MOLECULAR ANALYSIS OF THE DHPS GENE IN PLASMODIUM FALCIPARUM USING CLINICAL ISOLATES FROM DALOA TOWN IN CÔTE D’IVOIRE

Abstract

Plasmodium falciparum, the protozoan responsible for malaria, has repeatedly developed resistance to antimalarial drugs, thereby thwarting efforts to malaria control and elimination. These resistances have contributed significantly to an increase in malaria-related mortality. Among the molecular markers of resistance, point mutations in the dihydropteroate synthase (dhps) gene confer resistance to sulfadoxine in P. falciparum. The combination of its alleles is strongly correlated with the resistant phenotype. This study aimed to assess the resistance of Plasmodium falciparum to sulfadoxine in patients consulting at the Daloa Regional Hospital Centre (CHR), Côte d’Ivoire. The method involved PCR amplification followed by enzymatic digestion (PCR-RFLP) using the MnlI enzyme. A Total of 380 patients took part in the study, of whom 262 cases were confirmed by thick smear. Of these 262 isolates, 175 samples with high parasitaemia (≥ 1,000 trophozoites/µL) underwent molecular testing; of these, 148 (84.57%) tested positive by PCR amplification. Enzymatic digestion revealed 36 mutant isolates (24.32%) compared with 112 isolates (75.68%) of wild-type phenotype. These results from a cross-sectional study at Daloa CHR confirm the circulation of sulfadoxine-resistant P. falciparum isolates in this area and highlight the need to strengthen surveillance of chemoresistance to antimalarial drugs used in intermittent preventive treatment (IPT), particularly the sulfadoxine-pyrimethamine combination. A future research direction will involve combining an in vivo study of chemosensitivity to sulfadoxine-pyrimethamine with a joint analysis of the dhfr and dhps genes of P. falciparum.