Molecular monitoring of Plasmodium falciparum super-resistance to sulfadoxine-pyrimethamine in Tanzania

作者：Kavishe Reginald A; Kaaya Robert D; Nag Sidsel; Krogsgaard Camilla; Notland Jakob Gin**ak; Kavishe Adellaida A; Ishengoma Deus; Roper Cally; Alifrangis Michael

来源：Malaria Journal, 2016, 15(1): 335.

DOI：10.1186/s12936-016-1387-2

• Plasmodium falciparum
• Sulfadoxine-pyrimethamine
• SP-resistance
• SP-super resistance
• Anti-malarial drugs
• Tanzania
• Drug resistance
• Malaria
• Mutations
• Parasites
• Polymorphisms

Background: Sulfadoxine-pyrimethamine (SP) is recommended for prophylactic treatment of malaria in pregnancy while artemisinin combination therapy is the recommended first-line anti-malarial treatment. Selection of SP resistance is ongoing since SP is readily available in health facilities and in private drug shops in sub-Saharan Africa. This study reports on the prevalence and distribution of Pfdhps mutations A540E and A581G in Tanzania. When found together, these mutations confer high-level SP resistance (sometimes referred to as 'super-resistance'), which is associated with loss in protective efficacy of SP-IPTp.
Methods: DNA samples were extracted from malaria-positive blood samples on filter paper, used malaria rapid diagnostic test strips and whole blood collected from eight sites in seven administrative regions of Tanzania. PCR-RFLP and SSOP-ELISA techniques were used to genotype the A540E and A581G Pfdhps. Data were analysed using SPSS version 18 while Chi square and/or Fischer Exact tests were used to compare prevalence between regions.
Results: A high inter-regional variation of Pfdhps-540E was observed (chi(2) = 76.8, p < 0.001). High inter-regional variation of 581G was observed (FE = 85.3, p < 0.001). Both Tanga and Kagera were found to have the highest levels of SP resistance. A high prevalence of Pfdhps-581G was observed in Tanga (56.6 %) in northeastern Tanzania and in Kagera (20.4 %) in northwestern Tanzania and the 540-581 EG haplotype was found at 54.5 and 19.4 %, respectively. Pfdhps-581G was not detected in Pwani and Lindi regions located south of Tanga region.
Conclusions: Selection of SP super-resistant Pfdhps A581G is highest in northern Tanzania. Variation in distribution of SP resistance is observed across the country: northeastern Tanga region and northwestern Kagera region have highest prevalence of SP super-resistance markers, while in Pwani and Lindi in the southeast the prevalence of super-resistance was zero. More studies should be conducted to understand the factors underlying the remarkable heterogeneity in SP resistance in the country.

• 出版日期2016-6-23
• 单位河北医科大学