High prevalence of the 437G mutation associated with sulfadoxine resistance among Plasmodium falciparum clinical isolates from Iran, three years after the introduction of sulfadoxine-pyrimethamine

The absence of quintuple mutations in the examined isolates supports the continued use of SP as the treatment of choice for uncomplicated malaria as a partner drug to artemisinin combination therapy in Iran. However, the increase in the triple pfdhfr/pfdhps (R59N108/G437) mutant haplotypes indicates that the P. falciparum parasite populations have the potential to evolve into dhfr/dhps quintuple mutants in the near future. Therefore, monitoring the status of dhps alleles as a predictor of the development of clinical resistance to sulfadoxine should be a high priority in this region.