Molecular surveillance of antimalarial drug resistance markers in the pfcrt, pfmdr1 and pfmrp1 genes of Plasmodium falciparum isolates from southeastern Iran

The emergence and spread of Plasmodium falciparum resistance to artemisinin and its partner drugs pose a major challenge to malaria elimination efforts. Continuous monitoring of resistance-associated molecular markers provides valuable insights into the emergence of resistant genotypes and their geographical distribution. In this study, we investigated mutations linked to antimalarial drug resistance in the pfcrt , pfmdr1 , and pfmrp1 genes among 100 P. falciparum isolates collected from southeastern Iran during 2022–2023 and compared the findings with data from the same region a decade earlier. Point mutations were genotyped using PCR–RFLP. Molecular analysis demonstrated a high prevalence (95%) of the pfcrt K76 T mutation. In pfmdr1 , no mutations were observed at codons 1034, 1042, or 1246; however, the N86 Y and Y184 F mutations were detected in 3.75% and 51.25% of isolates, respectively. Comparative analysis between the previous (2007–2010) and current (2022–2023) studies revealed a significant increase in the wild-type allele for N86 Y and the mutant allele for Y184 F . In pfmrp1 , mutations at H191 Y , S437 A , I876 V , and F1390 I were identified in 68.75%, 85%, 78.75%, and 46.25% of isolates, respectively, while no mutation was observed at K1466 R . The predominant pfmdr1 haplotype shifted from wild-type (50%) in the previous study to the single-mutation haplotype N 86 F 184 S 1034 N 1042 D 1246 (50%) in the current study. Combined haplotype analysis of all three genes revealed a decrease in one major haplotype T 76 N 86 Y 184 S 1043 N 1042 D 1246 Y 191 A 437 V 876 F 1390 K 1466 (from 23.5 to 3.75%) and an increase in haplotype T 76 N 86 Y 184 S 1043 N 1042 D 1246 Y 191 A 437 V 876 I 1390 K 1466 (from 7 to 23.75%) over the same period. The persistence of the pfcrt K76 T mutant allele despite the withdrawal of Chloroquine from the treatment policy in Iran may be attributable to the co-endemicity of P. vivax in the study area. The increasing prevalence of the N 86 F 184 S 1034 N 1042 D 1246 pfmdr1 haplotype is of concern, given its reported association with reduced susceptibility to lumefantrine. Although mutant pfmrp1 alleles were detected at relatively high frequencies, current evidence does not suggest an immediate threat to the efficacy of artemether–lumefantrine in the studied population.