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Ex vivo Sensitivity Profile of Plasmodium falciparum Clinical Isolates to a Panel of Antimalarial Drugs in Ghana 13 Years After National Policy Change

Authors Ofori MF, Kploanyi EE, Mensah BA, Dickson EK, Kyei-Baafour E, Gyabaa S, Tetteh M, Koram KA, Abuaku BK, Ghansah A

Received 3 December 2020

Accepted for publication 9 January 2021

Published 28 January 2021 Volume 2021:14 Pages 267—276


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 2

Editor who approved publication: Professor Suresh Antony

Michael Fokuo Ofori,1,* Emma E Kploanyi,1 Benedicta A Mensah,2 Emmanuel K Dickson,1 Eric Kyei-Baafour,1 Sampson Gyabaa,3 Mary Tetteh,4 Kwadwo A Koram,2 Benjamin K Abuaku,2,* Anita Ghansah1,5,*

1Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana; 2Epidemiology Department, Noguchi Memorial Institute for Medical Research,University of Ghana, Legon, Accra, Ghana; 3Ewim Polyclinic, Ghana Health Service, Cape Coast, Ghana; 4Begoro District Hospital, Ghana Health Service, Begoro, Ghana; 5Parasitology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana

*These authors contributed equally to this work

Correspondence: Michael Fokuo Ofori
Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Post Office Box LG581, Legon, Ghana
Tel +233 244 715975
Fax +233 302 502182

Purpose: Malaria continues to be a major health issue globally with almost 85% of the global burden and deaths borne by sub-Saharan Africa and India. Although the current artemisinin derived combination therapies in Ghana are still efficacious against the Plasmodium falciparum (Pf) parasite, compounding evidence of artemisinin and amodiaquine resistance establish the need for a full, up-to-date understanding and monitoring of antimalarial resistance to provide evidence for planning control strategies.
Materials and Methods: The study was cross-sectional and was conducted during the peak malaria transmission seasons of 2015, 2016, and 2017 in two ecological zones of Ghana. Study participants included children aged 6 months to 14 years. Using ex vivo 4,6-diamidino-2-phenylindole (DAPI) drug sensitivity assay, 330 Pf isolates were used to investigate susceptibility to five antimalarial drugs: chloroquine (CQ), amodiaquine (AMD) dihydroartemisinin (DHA), artesunate (ART) and mefloquine (MFQ).
Results: The pooled geometric mean IC50S (GMIC50) of the five drugs against the parasites from Cape Coast and Begoro were 15.5, 42.4, 18.9, 4.6 and 27.3nM for CQ, AMD, DHA, ART, and MFQ, respectively. The GMIC50 values for CQ (p< 0.001), ART (p< 0.011) and DHA (p< 0.018) were significantly higher for Cape Coast isolates as compared to Begoro isolates. However, GMIC50 estimates for MFQ (p< 0.022) were significantly higher for Begoro isolates. Positive correlations were found between each pair of drugs with the weakest found between MFQ and DHA (r = 0.34;p< 0.001), and the strongest between ART and DHA (r =0.66; p< 0.001).
Conclusion: The parasites showed reduced sensitivities to three (AMD, DHA and MFQ) out of the five drugs assessed. The study also demonstrated the continual return of chloroquine-sensitive parasites after 13 years of its withdrawal as the first-line drug for the treatment of uncomplicated malaria in Ghana. The ex vivo DAPI assay is a reliable method for assessing antimalarial drug sensitivities of Pf field isolates under field settings.

Keywords: malaria, Plasmodium falciparum, anti-malarial drugs, field isolates, DAPI, uncomplicated malaria

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