Scientific Reports (May 2021)

Artemisinin combination therapy fails even in the absence of Plasmodium falciparum kelch13 gene polymorphism in Central India

  • Sabyasachi Das,
  • Amrita Kar,
  • Subhankar Manna,
  • Samaresh Mandal,
  • Sayantani Mandal,
  • Subhasis Das,
  • Bhaskar Saha,
  • Amiya Kumar Hati

DOI
https://doi.org/10.1038/s41598-021-89295-0
Journal volume & issue
Vol. 11, no. 1
pp. 1 – 12

Abstract

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Abstract Artemisinin is the frontline fast-acting anti-malarial against P. falciparum. Emergence and spread of resistant parasite in eastern-India poses a threat to national malaria control programs. Therefore, the objective of our study is to evaluate the artesunate-sulfadoxine-pyrimethamine efficacy in Central India. 180 monoclonal P. falciparum-infected patients received standard ASSP therapy during August 2015–January 2017, soon after diagnosis and monitored over next 42-days. Artemisinin-resistance was assessed through in-vivo parasite clearance half-life (PC1/2), ex-vivo ring-stage survivability (RSA), and genome analysis of kelch13 and other candidate gene (pfcrt, pfmdr1, pfatpase 6, pfdhfr and pfdhps). Of 180 P. falciparum positive patients, 9.5% showed increased PC1/2 (> 5.5 h), among them eleven isolates (6.1%) showed reduced sensitivity to RSA. In 4.4% of cases, parasites were not cleared by 72 h and showed prolonged PC1/2(5.6 h) (P < 0.005) along with significantly higher RSA (2.2%) than cured patients (0.4%). None of day-3 positive isolates contained the pfkelch13 mutation implicated in artemisinin resistance. Parasite recrudescence was observed in 5.6% patients, which was associated with triple dhfr–dhps (A16 I 51 R 59 N 108I164–S436 G 437K540 G 581 T 613 ) combination mutation. Emergence of reduced sensitivity to artesunate-sulfadoxine-pyrimethamine, in central India highlighted the risk toward spread of resistant parasite across different parts of India. Day-3 positive parasite, featuring the phenotype of artemisinin-resistance without pfkelch13 mutation, suggested kelch13-independent artemisinin-resistance.