Molecular surveillance of Plasmodium falciparum drug resistance in the Republic of Congo: four and nine years after the introduction of artemisinin-based combination therapy

Malaria Journal

Research

Felix Koukouikila-Koussounda¹  Mandingha K. Etoka-Beka¹  Francine Ntoumi²  Thirumalaisamy P. Velavan³  Christian N. Nguetse⁴  Kossiwa Clarisse Kokou⁴  Charles Nchotebah Nkonganyi⁴  Sankarganesh Jeyaraj⁴ 

[1] Fondation Congolaise pour la Recherche Médicale (FCRM), Brazzaville, Republic of Congo;Fondation Congolaise pour la Recherche Médicale (FCRM), Brazzaville, Republic of Congo;Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany;Fondation Congolaise pour la Recherche Médicale (FCRM), Brazzaville, Republic of Congo;Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany;Duy Tan University, Da Nang, Vietnam;Vietnamese-German Centre for Medical Research, Hanoi, Vietnam;Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany;

关键词: Malaria;    Plasmodium falciparum;    Pfcrt;    Pfmdr1;    Pfatp6;    Pfk13;    Anti-malarial resistance;    ACT;    Republic of Congo;   

DOI  :  10.1186/s12936-017-1816-x

 received in 2017-02-16, accepted in 2017-04-09,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundResistance to anti-malarial drugs hinders efforts on malaria elimination and eradication. Following the global spread of chloroquine-resistant parasites, the Republic of Congo adopted artemisinin-based combination therapy (ACT) in 2006 as a first-line treatment for uncomplicated malaria. To assess the impacts after implementation of ACT, a molecular surveillance for anti-malarial drug resistance was conducted in Congo 4 and 9 years after the introduction of ACT.MethodsBlood samples of 431 febrile children aged 1–10 years were utilized from two previous studies conducted in 2010 (N = 311) and 2015 (N = 120). All samples were screened for malaria parasites using nested PCR. Direct sequencing was used to determine the frequency distribution of genetic variants in the anti-malarial drug-resistant Plasmodium falciparum genes (Pfcrt, Pfmdr1, Pfatp6, Pfk13) in malaria-positive isolates.ResultsOne-hundred and nineteen (N = 70 from 2010 and N = 49 from 2015) samples were positive for P. falciparum. A relative decrease in the proportion of chloroquine-resistant haplotype (CVIET) from 100% in 2005, 1 year before the introduction and implementation of ACT in 2006, to 98% in 2010 to 71% in 2015 was observed. Regarding the multidrug transporter gene, a considerable reduction in the frequency of the mutations N86Y (from 73 to 27%) and D1246Y (from 22 to 0%) was observed. However, the prevalence of the Y184F mutation remained stable (49% in 2010 compared to 54% in 2015). Isolates carrying the Pfatp6 H243Y was 25% in 2010 and this frequency was reduced to null in 2015. None of the parasites harboured the Pfk13 mutations associated with prolonged artemisinin clearance in Southeast Asia. Nevertheless, 13 new Pfk13 variants are reported among the investigated isolates.ConclusionThe implementation of ACT has led to the decline in prevalence of chloroquine-resistant parasites in the Republic of Congo. However, the constant prevalence of the PfMDR1 Y184F mutation, associated with lumefantrine susceptibility, indicate a selective drug pressure still exists. Taken together, this study could serve as the basis for epidemiological studies monitoring the distribution of molecular markers of artemisinin resistance in the Republic of Congo.

【 授权许可】

CC BY   
© The Author(s) 2017