Joste V. auteur aut IRD Coppée R. auteur aut IRD Bailly Justine auteur aut IRD Rakotoarivony Y. auteur aut IRD Toko Tchokoteu F.G. auteur aut IRD Achache S. auteur aut IRD Pradines B. auteur aut IRD Cottrell Gilles auteur aut IRD Ariey F. auteur aut IRD Khim N. auteur aut IRD Popovici J. auteur aut IRD Mita T. auteur aut IRD Groger M. auteur aut IRD Ramharter M. auteur aut IRD Egbo T. auteur aut IRD Juma D.W. auteur aut IRD Akala H. auteur aut IRD Houzé S. auteur aut IRD Clain J. auteur aut IRD Abou-Bacar A. auteur aut IRD Agnamey P. auteur aut IRD Ait-Ammar N. auteur aut IRD Angoulvant A. auteur aut IRD Argy N. auteur aut IRD Azjenberg D. auteur aut IRD Basmaciyan L. auteur aut IRD Bastien P. auteur aut IRD Belaz S. auteur aut IRD Belkadi G. auteur aut IRD Bellanger A.P. auteur aut IRD Bemba D. auteur aut IRD Berry A. auteur aut IRD Botterel F. auteur aut IRD Bouden F. auteur aut IRD Bougnoux M.E. auteur aut IRD Bouzayene A. auteur aut IRD Bret L. auteur aut IRD Bretagne S. auteur aut IRD Brumpt C. auteur aut IRD Buret B. auteur aut IRD Caraux-Paz P. auteur aut IRD Cheruiyot A. auteur aut IRD Chlilek A. auteur aut IRD Clauser S. auteur aut IRD Cojean S. auteur aut IRD Cuisenier B. auteur aut IRD Dahane N. auteur aut IRD Dannaoui E. auteur aut IRD Dard C. auteur aut IRD Dardé M.L. auteur aut IRD De Gentile L. auteur aut IRD Debourgogne A. auteur aut IRD Dechavanne Célia auteur aut IRD et al. auteur aut IRD text journalArticle eng text/pdf reformatted digital access Background Mutations in the Plasmodium falciparum dhfr gene confer resistance to pyrimethamine, which is widely used for malaria chemoprevention in Africa. We aimed to evaluate the frequency and evolution of dhfr mutations Plasmodium ovale spp in Africa and their functional consequences, which are incompletely characterised. Methods We analysed dhfr mutations and their frequencies in P ovale spp isolates collected between Feb 1, 2004, Aug 31, 2023, from the French National Malaria Reference Centre collection and from fi eld studies in Benin, Gabon, Kenya. Genetic patterns of positive selection were investigated. Full-length recombinant wild-type and mutant DHFR enzymes from both P ovale curtisi and P ovale wallikeri were expressed in bacteria to test whether the most common mutations reduced pyrimethamine susceptibility. Findings We included 518 P ovale spp samples (314 P ovale curtisi and 204 P ovale wallikeri ). In P ovale curtisi Ala15Ser-Ser58Arg was the most common dhfr mutation (39%; 124 of 314 samples). In P ovale wallikeri , mutations were less frequent, with Phe57Leu-Ser58Arg reaching 17% (34 of 204 samples). These two mutants were the most prevalent in central and east Africa and were fi xed in Kenyan isolates. We detected six and four other non-synonymous mutations, representing 8% (24 isolates) and 2% ( fi ve isolates) of the P ovale curtisi P ovale wallikeri isolates, respectively. Whole-genome sequencing and microsatellite analyses revealed reduced genetic diversity around the mutant pocdhfr and powdhfr genes. The mutant DHFR proteins showed structural changes at the pyrimethamine binding site in-silico, con fi rmed by a 4-times increase in pyrimethamine half-maximal inhibitory concentration in an Escherichia coli growth assay for the Phe57Leu-Ser58Arg mutant 50-times increase for the Ala15Ser-Ser58Arg mutant, compared with the wild-type counterparts. Interpretation The widespread use of sulfadoxine - pyrimethamine for malaria chemoprevention might have exerted fortuitous selection pressure for dhfr mutations in P ovale spp. This calls for closer monitoring of dhfr and dhps mutations in P ovale spp. specialized AFRIQUE SUBSAHARIENNE BENIN GABON KENYA 052ANOPAL03 050MEDECI 5 7 669-678 2024 2666-5247 https://www.documentation.ird.fr/hor/fdi:010091513 10.1016/s2666-5247(24)00054-5 2666-5247 [F B010091513] https://www.documentation.ird.fr/hor/fdi:010091513 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2024-08/010091513.pdf IRD - Base Horizon / Pleins textes 2024-07-23 2025-11-06 fdi:010091513 fre