Characterization of Plasmodium falciparum genes associated with drug resistance in Hodh Elgharbi, a malaria hotspot near Malian–Mauritanian border

Abstract

BackgroundA malaria hotspot in the southeastern region of Mauritania, near the Malian border, may hamper malaria control strategies. The objectives were to estimate the prevalence of genetic polymorphisms associated with drug resistance in Plasmodium falciparum isolates and establish baseline data.MethodsThe study was conducted in two malaria-endemic areas in Hodh Elgharbi, situated in the Malian–Mauritanian border area. Blood samples were collected from symptomatic patients. Single nucleotide polymorphisms in Pfcrt, Pfmdr1, Pfdhfr, and Pfdhps were genotyped using PCR-restriction fragment length polymorphism, DNA sequencing and primer extension. The Pfmdr1 gene copy number was determined by real-time PCR.ResultsOf 280 P. falciparum-infected patients, 193 (68.9%) carried the Pfcrt 76T mutant allele. The Pfmdr1 86Y and 184F mutations were found in 61 (23.1%) of 264 isolates and 167 (67.6%) of 247 samples that were successfully genotyped, respectively. Pfmdr1 mutant alleles 1034C, 1042D and 1246Y were rarely observed. Of 102 P. falciparum isolates analysed, ten (9.8%) had more than one copy of Pfmdr1 gene. The prevalence of isolates harbouring at least triple mutant Pfdhfr 51I, 59R, 108 N/T was 42% (112/268), of which 42 (37.5%) had an additional Pfdhps 437G mutation. The Pfdhps 540E mutation was observed in four isolates (1.5%), including three associated with Pfdhfr triple mutant. Only two quintuple mutants (Pfdhfr-51I-59R-108N Pfdhps-437G-540E) were observed.ConclusionsThe observed mutations in Pfdhfr, Pfdhps, Pfmdr1, and Pfcrt may jeopardize the future of seasonal malaria chemoprevention based on amodiaquine-sulfadoxine-pyrimethamine, intermittent preventive treatment for pregnant women using sulfadoxine-pyrimethamine, and treatment with artesunate-amodiaquine. Complementary studies should be carried out to document the distribution, origin and circulation of P. falciparum populations in this region and more widely in the country to assess the risk of the spread of resistance.

Oasis Malaria, Northern Mauritania1

“…We report that P. falciparum also has been diagnosed among febrile patients permanently residing in Atar, albeit at a relatively low rate, a finding that is consistent with previous studies on the geographic distribution of Plasmodium species in Mauritania ( 31 – 34 ). However, the data in our study suggest that P. falciparum might have been introduced to Atar by travelers visiting malaria-endemic regions to the south.…”

High prevalence of Pfdhfr–Pfdhps quadruple mutations associated with sulfadoxine–pyrimethamine resistance in Plasmodium falciparum isolates from Bioko Island, Equatorial Guinea

“…For the dominant mutant haplotype C IRN I (86.83%) and the double mutant haplotype C I C N I (5.99%), the results are consistent with previous studies in EG and Central Africa [ 4 , 10 , 32 , 33 ]. If the C IRN I haplotype is found concurrently with the Pfdhps mutations, it is associated with a high level of resistance [ 34 ]. The reported prevalence of the Pfdhfr triple mutation was also lower than those previously reported at the site where the proportion of the Pfdhfr triple mutation reached a frequency of 97%.…”

“…The saturation of the Pfdhfr triple mutants could further induce the Pfdhps mutants, and thus, the presence of quadruple mutants (C IRN I-S G KAA) was common [ 40 ]. Although quintuple mutant genotypes (C IRN I-S GE AA) are highly linked to SP failure [ 34 ], this mutant was detected at a rate of 4.62% (Table 3 ). WHO recommends surveillancefor this genotype and inhibition of IPTp-SP when the prevalence of this quintuple mutant exceeds 50% [ 31 ].…”

A snapshot of Plasmodium falciparum malaria drug resistance markers in Sudan: a pilot study

“…The microscopic diagnosis was confirmed using the primers described previously [ 16 ]. Genotyping of the specific point mutations in the P. falciparum genome was done using the Sanger sequencing method by using the primers sets for Pfcrt , Pfmdr-1 , Pfdhfr , and Pfdhps genes as described previously [ 17 ]. PCR amplicons were sequenced in both directions using the forward and reverse primers for each gene to exclude any base-calling errors that could be obtained during sequencing.…”