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Prevalence of Plasmodium falciparum parasites resistant to sulfadoxine/pyrimethamine in pregnant women in Yaoundé, Cameroon: emergence of highly resistant pfdhfr / pfdhps alleles

2015; Oxford University Press; Volume: 70; Issue: 9 Linguagem: Inglês

10.1093/jac/dkv160

1460-2091

Pamela Chauvin, Sandie Ménard, Xavier Iriart, Sandrine E. Nsango, Majoline T. Tchioffo, Luc Abate, Parfait Awono‐Ambene, Isabelle Morlais, Antoine Berry,

Research on Leishmaniasis Studies

To determine, 6 years after the adoption of intermittent preventive treatment of pregnant women with sulfadoxine/pyrimethamine (IPTp-SP) in Cameroon, (i) the polymorphism and prevalence of Plasmodium falciparum dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) gene mutations associated with sulfadoxine/pyrimethamine resistance and (ii) the consequences of sulfadoxine/pyrimethamine use in the selection of pfdhfr/pfdhps alleles. pfdhfr and pfdhps genes from P. falciparum isolates collected in Yaoundé (Cameroon) from pregnant women with symptomatic malaria before taking IPTp-SP [SP− group (control) (n = 51)] or afterwards [SP+ group (n = 49)] were sequenced. The pfdhfr N51I, C59R, S108N triple mutant had a prevalence close to 100% (96/100) and no mutations at codons 50 and 164 were detected in either of the groups. The most frequent pfdhps mutation was A437G with a prevalence of 76.5% (39/51) in the SP− group, which was significantly higher in pregnant women who took sulfadoxine/pyrimethamine [95.9% (47/49)] (P = 0.012). Our study confirmed the presence of the pfdhps K540E mutation in Cameroon, but it remained rare. The prevalence of pfdhps A581G and A613S mutations had increased [5.9% (3/51) and 11.8% (6/51) in the control group, respectively] since the last studies in 2005. Surprisingly, the new pfdhps I431V mutation was detected, at a prevalence of 9.8% (5/51), and was found to be associated with other pfdhfr/pfdhps alleles to form an octuple N51I, C59R, S108N/I431V, S436A, A437G, A581G, A613S mutant. Significant changes were found in pfdhps polymorphism. In particular, we observed several parasites carrying eight mutations in pfdhfr/pfdhps genes, which are very susceptible to having a high level of resistance to sulfadoxine/pyrimethamine.