Resistance profile of the Plasmodium falciparum dihydropteroate synthase gene in three hospitals in the city of Ndjamena, Chad

Malaria is a potentially fatal febrile hemolytic parasitic disease caused by Plasmodium species. The objective of this study was to determine the genetic resistance profile of the Plasmodium falciparum dihydropteroate synthase (Pfdhps) gene in three health facilities in the city of N’Djamena. This was a cross-sectional analytical study. Samples were collected from 220 consenting patients. Plasmodium falciparum infection was diagnosed using RDTs and thick blood smears to determine parasite density. Positive samples were spotted on Whatman paper. DNA was extracted using the Chelex-100 method and amplified by semi-nested PCR to detect the presence of the Pfdhps resistance gene. The A437G and A581G mutations were identified using the restriction fragment length polymorphism (RFLP) method. Data were analyzed using SPSS version 26. The overall prevalence of Plasmodium falciparum infection was 39.54%, with the 0–5-year age group showing the highest prevalence. The Pfdhps resistance gene was detected in 37.93% of positive cases, most frequently in the 5–35-year age group (45.61%). The A437G mutation was found in 9.09% of samples, while the A581G mutation was detected in 54.54%. The A437G mutation was more common in individuals aged 5–35 years (42.10%), whereas the A581G mutation was more prevalent in men (30%) and in individuals who reported using Fansidar (30%). This study confirms the presence of the Pfdhps resistance gene in N’Djamena across three health facilities. The high frequency of the A437G and A581G mutations underscores the need to strengthen monitoring of antimalarial drug resistance.