scholarly journals Plasmodium falciparum Genetic Diversity in Continental Equatorial Guinea before and after Introduction of Artemisinin-Based Combination Therapy

2016 ◽  
Vol 61 (1) ◽  
Author(s):  
Mónica Guerra ◽  
Rita Neres ◽  
Patrícia Salgueiro ◽  
Cristina Mendes ◽  
Nicolas Ndong-Mabale ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Drug Resistance ◽  
Plasmodium Falciparum ◽  
Combination Therapy ◽  
Microsatellite Loci ◽  
Point Mutations ◽  
Artemisinin Resistance ◽  
Equatorial Guinea ◽  
Content Type ◽  
Before And After

ABSTRACT Efforts to control malaria may affect malaria parasite genetic variability and drug resistance, the latter of which is associated with genetic events that promote mechanisms to escape drug action. The worldwide spread of drug resistance has been a major obstacle to controlling Plasmodium falciparum malaria, and thus the study of the origin and spread of associated mutations may provide some insights into the prevention of its emergence. This study reports an analysis of P. falciparum genetic diversity, focusing on antimalarial resistance-associated molecular markers in two socioeconomically different villages in mainland Equatorial Guinea. The present study took place 8 years after a previous one, allowing the analysis of results before and after the introduction of an artemisinin-based combination therapy (ACT), i.e., artesunate plus amodiaquine. Genetic diversity was assessed by analysis of the Pfmsp2 gene and neutral microsatellite loci. Pfdhps and Pfdhfr alleles associated with sulfadoxine-pyrimethamine (SP) resistance and flanking microsatellite loci were investigated, and the prevalences of drug resistance-associated point mutations of the Pfcrt, Pfmdr1, Pfdhfr, and Pfdhps genes were estimated. Further, to monitor the use of ACT, we provide the baseline prevalences of K13 propeller mutations and Pfmdr1 copy numbers. After 8 years, noticeable differences occurred in the distribution of genotypes conferring resistance to chloroquine and SP, and the spread of mutated genotypes differed according to the setting. Regarding artemisinin resistance, although mutations reported as being linked to artemisinin resistance were not present at the time, several single nucleotide polymorphisms (SNPs) were observed in the K13 gene, suggesting that closer monitoring should be maintained to prevent the possible spread of artemisinin resistance in Africa.

scholarly journals Surveillance of Artemisinin Resistance in Plasmodium falciparum in India Using the kelch13 Molecular Marker

2015 ◽  
Vol 59 (5) ◽  
pp. 2548-2553 ◽  
Author(s):  
Neelima Mishra ◽  
Surendra Kumar Prajapati ◽  
Kamlesh Kaitholia ◽  
Ram Suresh Bharti ◽  
Bina Srivastava ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Molecular Marker ◽  
Association Studies ◽  
Point Mutations ◽  
Artemisinin Resistance ◽  
Content Type ◽  
Combination Treatments ◽  
The Status ◽  
Genome Association ◽  
Efficacy Studies

ABSTRACTMalaria treatment in Southeast Asia is threatened with the emergence of artemisinin-resistantPlasmodium falciparum. Genome association studies have strongly linked a locus onP. falciparumchromosome 13 to artemisinin resistance, and recently, mutations in the kelch13 propeller region (Pfk-13) were strongly linked to resistance. To date, this information has not been shown in Indian samples.Pfk-13mutations were assessed in samples from efficacy studies of artemisinin combination treatments in India. Samples were PCR amplified and sequenced from codon 427 to 727. Out of 384 samples, nonsynonymous mutations in the propeller region were found in four patients from the northeastern states, but their presence did not correlate with ACT treatment failures. This is the first report ofPfk-13point mutations from India. Further phenotyping and genotyping studies are required to assess the status of artemisinin resistance in this region.

scholarly journals Molecular Epidemiology of Plasmodium falciparum kelch13 Mutations in Senegal Determined by Using Targeted Amplicon Deep Sequencing

2017 ◽  
Vol 61 (3) ◽  
Author(s):  
Eldin Talundzic ◽  
Yaye D. Ndiaye ◽  
Awa B. Deme ◽  
Christian Olsen ◽  
Dhruviben S. Patel ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Plasmodium Falciparum ◽  
Deep Sequencing ◽  
Artemisinin Resistance ◽  
Potential Drug ◽  
Drug Pressure ◽  
Low Frequencies ◽  
Content Type ◽  
Public Health Activity ◽  
Codon Positions

ABSTRACT The emergence of Plasmodium falciparum resistance to artemisinin in Southeast Asia threatens malaria control and elimination activities worldwide. Multiple polymorphisms in the P. falciparum kelch gene found in chromosome 13 (Pfk13) have been associated with artemisinin resistance. Surveillance of potential drug resistance loci within a population that may emerge under increasing drug pressure is an important public health activity. In this context, P. falciparum infections from an observational surveillance study in Senegal were genotyped using targeted amplicon deep sequencing (TADS) for Pfk13 polymorphisms. The results were compared to previously reported Pfk13 polymorphisms from around the world. A total of 22 Pfk13 propeller domain polymorphisms were identified in this study, of which 12 have previously not been reported. Interestingly, of the 10 polymorphisms identified in the present study that were also previously reported, all had a different amino acid substitution at these codon positions. Most of the polymorphisms were present at low frequencies and were confined to single isolates, suggesting they are likely transient polymorphisms that are part of naturally evolving parasite populations. The results of this study underscore the need to identify potential drug resistance loci existing within a population, which may emerge under increasing drug pressure.

scholarly journals Screening for antifolate and artemisinin resistance in Plasmodium falciparum clinical isolates from three hospitals of Eritrea

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 628
Author(s):  
Harriet Natabona Mukhongo ◽  
Johnson Kang'ethe Kinyua ◽  
Yishak Gebrekidan Weldemichael ◽  
Remmy Wekesa Kasili
Keyword(s):  
Drug Resistance ◽  
Plasmodium Falciparum ◽  
Point Mutations ◽  
Artemisinin Resistance ◽  
Pcr Amplification ◽  
Clinical Isolates ◽  
Genetic Mechanism ◽  
Dried Blood Spot ◽  
Nested Polymerase Chain Reaction ◽  
Blood Spot

Background: Antimalarial drug resistance is a major challenge hampering malaria control and elimination. Plasmodium falciparum, the leading causative parasite species, has developed resistance to basically all antimalarials. Continued surveillance of drug resistance using genetic markers provides important molecular data for treatment policies. This study sought to verify the genetic mechanism of resistance to sulfadoxine-pyrimethamine and assess the occurrence of point mutations associated with artemisinin resistance in P. falciparum clinical isolates from Eritrea. Methods: Nineteen dried blood spot samples were collected from patients visiting Adi Quala, Keren and Gash Barka Hospitals, Eritrea. The patients were followed up after receiving treatment with first line artesunate-amodiaquine. Nested polymerase chain reaction and Sanger sequencing techniques were employed to genotype point mutations in the P. falciparum bifunctional dihydrofolate reductase-thymidylate synthase (Pfdhfr, PF3D7_0417200), dihydropteorate synthase (Pfdhps, PF3D7_0810800) and kelch 13 (PfK13, PF3D7_1343700) genes. Results: Eight of nineteen (42%) of the dried blood spot samples were successful for PCR-amplification. Data analyses of the PCR-positive isolates revealed the following point mutations: Pfdhfr N51I in four isolates, C59R in one isolate, S108N in four isolates, a rare non-synonymous substitution V45A in four isolates and Pfdhps K540E in four isolates. No PfK13 point mutations were reported. Conclusions: Pfdhfr C59R and Pfdhps K540E point mutations are reliable markers for the sulfadoxine-pyrimethamine quintuple mutant haplotype combination. These findings highlight first reports in Eritrea, which verify the underlying genetic mechanism of antifolate resistance. Continuous monitoring of the PfK13 marker is recommended.

scholarly journals Polymorphism Analysis of pfmdr1 Gene in Plasmodium falciparum Isolates 11 Years Post-adoption of Artemisinin-based Combination Therapy in Saudi Arabia

2021 ◽  
Author(s):  
Hesham M. Al-Mekhlafi ◽  
Aymen M. Madkhali ◽  
Ahmed A. Abdulhaq ◽  
Wahib M. Atroosh ◽  
Ahmad Hassn Ghzwani ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Plasmodium Falciparum ◽  
Saudi Arabia ◽  
Combination Therapy ◽  
Point Mutations ◽  
Multi Drug Resistance ◽  
Polymorphism Analysis ◽  
Wild Allele ◽  
High Prevalence ◽  
Parasitaemia Level

Abstract A total of 227 Plasmodium falciparum isolates from Jazan region, southwestern Saudi Arabia were amplified for the P. falciparum multi-drug resistance 1 (pfmdr1) gene to detect point mutations 11 years after the introduction of artemisinin-based combination therapy (ACT) in Saudi Arabia. The pfmdr1 86Y mutation was found in 11.5% (26/227) of the isolates while the N86 wild allele was detected in 88.5%. Moreover, 184F point mutations dominated (86.3%) the instances of pfmdr1 polymorphism while no mutation was observed at codons 1034, 1042 and 1246. Three pfmdr1 haplotypes were identified, NFSND (74.9%), NYSND (13.7%) and YFSND (11.4%). Associations of the prevalence of 86Y mutation and YFSND haplotype with participants’ nationality, residency and parasitaemia level were found to be significant (P < 0.05). The findings revealed significant decline in the prevalence of the pfmdr1 86Y mutation in P. falciparum isolates from Jazan region over a decade after the implementation of ACT treatment. Moreover, the high prevalence of the NFSND haplotype might be indicative of the potential emergence of CQ-sensitive but artemether-lumefantrine-resistant P. falciparum strains since the adoption of ACT. Therefore, continuous monitoring of the molecular markers of antimalarial drug resistance in Jazan region is highly recommended.

scholarly journals The Malaria TaqMan Array Card Includes 87 Assays for Plasmodium falciparum Drug Resistance, Identification of Species, and Genotyping in a Single Reaction

2017 ◽  
Vol 61 (5) ◽  
Author(s):  
Suporn Pholwat ◽  
Jie Liu ◽  
Suzanne Stroup ◽  
Shevin T. Jacob ◽  
Patrick Banura ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Plasmodium Falciparum ◽  
Large Scale ◽  
Limit Of Detection ◽  
Artemisinin Resistance ◽  
Clinical Samples ◽  
Content Type ◽  
Antimalarial Resistance ◽  
Resistance Markers ◽  
Taqman Array

ABSTRACT Antimalarial drug resistance exacerbates the global disease burden and complicates eradication efforts. To facilitate the surveillance of resistance markers in countries of malaria endemicity, we developed a suite of TaqMan assays for known resistance markers and compartmentalized them into a single array card (TaqMan array card, TAC). We included 87 assays for species identification, for the detection of Plasmodium falciparum mutations associated with chloroquine, atovaquone, pyrimethamine, sulfadoxine, and artemisinin resistance, and for neutral single nucleotide polymorphism (SNP) genotyping. Assay performance was first optimized using DNA from common laboratory parasite lines and plasmid controls. The limit of detection was 0.1 to 10 pg of DNA and yielded 100% accuracy compared to sequencing. The tool was then evaluated on 87 clinical blood samples from around the world, and the malaria TAC once again achieved 100% accuracy compared to sequencing and in addition detected the presence of mixed infections in clinical samples. With its streamlined protocol and high accuracy, this malaria TAC should be a useful tool for large-scale antimalarial resistance surveillance.

scholarly journals Sustained Ex Vivo Susceptibility of Plasmodium falciparum to Artemisinin Derivatives but Increasing Tolerance to Artemisinin Combination Therapy Partner Quinolines in The Gambia

2017 ◽  
Vol 61 (12) ◽  
Author(s):  
Alfred Amambua-Ngwa ◽  
Joseph Okebe ◽  
Haddijatou Mbye ◽  
Sukai Ceesay ◽  
Fatima El-Fatouri ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Plasmodium Falciparum ◽  
Combination Therapy ◽  
Genomic Sequence ◽  
Sequence Data ◽  
Ex Vivo ◽  
Artemisinin Combination Therapy ◽  
Artemisinin Resistance ◽  
The Gambia ◽  
Microsatellite Variation

ABSTRACT Antimalarial interventions have yielded a significant decline in malaria prevalence in The Gambia, where artemether-lumefantrine (AL) has been used as a first-line antimalarial for a decade. Clinical Plasmodium falciparum isolates collected from 2012 to 2015 were analyzed ex vivo for antimalarial susceptibility and genotyped for drug resistance markers (pfcrt K76T, pfmdr1 codons 86, 184, and 1246, and pfk13) and microsatellite variation. Additionally, allele frequencies of single nucleotide polymorphisms (SNPs) from other drug resistance-associated genes were compared from genomic sequence data sets from 2008 (n = 79) and 2014 (n = 168). No artemisinin resistance-associated pfk13 mutation was found, and only 4% of the isolates tested in 2015 showed significant growth after exposure to dihydroartemisinin. Conversely, the 50% inhibitory concentrations (IC50s) of amodiaquine and lumefantrine increased within this period. pfcrt 76T and pfmdr1 184F mutants remained at a prevalence above 80%. pfcrt 76T was positively associated with higher IC50s to chloroquine. pfmdr1 NYD increased in frequency between 2012 and 2015 due to lumefantrine selection. The TNYD (pfcrt 76T and pfmdr1 NYD wild-type haplotype) also increased in frequency following AL implementation in 2008. These results suggest selection for pfcrt and pfmdr1 genotypes that enable tolerance to lumefantrine. Increased tolerance to lumefantrine calls for sustained chemotherapeutic monitoring in The Gambia to minimize complete artemisinin combination therapy (ACT) failure in the future.

scholarly journals Polymorphism analysis of pfmdr1 gene in Plasmodium falciparum isolates 11 years post-adoption of artemisinin-based combination therapy in Saudi Arabia

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Hesham M. Al-Mekhlafi ◽  
Aymen M. Madkhali ◽  
Ahmed A. Abdulhaq ◽  
Wahib M. Atroosh ◽  
Ahmad Hassn Ghzwani ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Plasmodium Falciparum ◽  
Saudi Arabia ◽  
Combination Therapy ◽  
Point Mutations ◽  
Multi Drug Resistance ◽  
Polymorphism Analysis ◽  
Wild Allele ◽  
High Prevalence ◽  
Parasitaemia Level

AbstractA total of 227 Plasmodium falciparum isolates from Jazan region, southwestern Saudi Arabia were amplified for the P. falciparum multi-drug resistance 1 (pfmdr1) gene to detect point mutations 11 years after the introduction of artemisinin-based combination therapy (ACT) in Saudi Arabia. The pfmdr1 86Y mutation was found in 11.5% (26/227) of the isolates while the N86 wild allele was detected in 88.5%. Moreover, 184F point mutations dominated (86.3%) the instances of pfmdr1 polymorphism while no mutation was observed at codons 1034, 1042 and 1246. Three pfmdr1 haplotypes were identified, NFSND (74.9%), NYSND (13.7%) and YFSND (11.4%). Associations of the prevalence of 86Y mutation and YFSND haplotype with participants’ nationality, residency and parasitaemia level were found to be significant (P < 0.05). The findings revealed significant decline in the prevalence of the pfmdr1 86Y mutation in P. falciparum isolates from Jazan region over a decade after the implementation of ACT treatment. Moreover, the high prevalence of the NFSND haplotype might be indicative of the potential emergence of CQ-sensitive but artemether-lumefantrine-resistant P. falciparum strains since the adoption of ACT. Therefore, continuous monitoring of the molecular markers of antimalarial drug resistance in Jazan region is highly recommended.

scholarly journals Novel K540N Mutation in Plasmodium falciparum Dihydropteroate Synthetase Confers a Lower Level of Sulfa Drug Resistance than Does a K540E Mutation

2011 ◽  
Vol 55 (5) ◽  
pp. 2481-2482 ◽  
Author(s):  
Vanshika Lumb ◽  
Yagya D. Sharma
Keyword(s):  
Drug Resistance ◽  
Plasmodium Falciparum ◽  
Point Mutations ◽  
Drug Resistant ◽  
Sulfa Drug ◽  
Content Type ◽  
E Coli ◽  
Content Model ◽  
Content System ◽  
Drug Resistant Parasite

ABSTRACTSulfadoxine (SDX) and sulfamethoxazole (SMX) each inhibit thePlasmodium falciparumdihydropteroate synthetase (PfDHPS), and certain point mutations in this enzyme yield the drug-resistant parasite. Using a simpleEscherichia colimodel system, we describe here the effect of the recently reported novel K540N mutation in PfDHPS on the level of SDX/SMX resistance. The survival rate of the transformedE. coli(DHPS-deficient strain) under different SDX or SMX concentrations revealed that the K540N mutation confers a lower level of drug resistance than its contemporary K540E mutation. Further, SMX was more effective than SDX in theE. colisystem.

scholarly journals The MSPDBL2 Codon 591 Polymorphism Is Associated with LumefantrineIn VitroDrug Responses in Plasmodium falciparum Isolates from Kilifi, Kenya

2014 ◽  
Vol 59 (3) ◽  
pp. 1770-1775 ◽  
Author(s):  
Lynette Isabella Ochola-Oyier ◽  
John Okombo ◽  
Leah Mwai ◽  
Steven M. Kiara ◽  
Lewa Pole ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Plasmodium Falciparum ◽  
Combination Therapy ◽  
High Frequency ◽  
Artemisinin Combination Therapy ◽  
Resistance Development ◽  
Content Type

ABSTRACTThe mechanisms of drug resistance development in thePlasmodium falciparumparasite to lumefantrine (LUM), commonly used in combination with artemisinin, are still unclear. We assessed the polymorphisms ofPfmspdbl2for associations with LUM activity in a Kenyan population. MSPDBL2 codon 591S was associated with reduced susceptibility to LUM (P= 0.04). The high frequency ofPfmspdbl2codon 591S in Kenya may be driven by the widespread use of lumefantrine in artemisinin combination therapy (Coartem).

scholarly journals A comprehensive analysis of drug resistance molecular markers and Plasmodium falciparum genetic diversity in two malaria endemic sites in Mali

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Seidina A. S. Diakité ◽  
Karim Traoré ◽  
Ibrahim Sanogo ◽  
Taane G. Clark ◽  
Susana Campino ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Drug Resistance ◽  
Plasmodium Falciparum ◽  
Molecular Markers ◽  
Malaria Transmission ◽  
Resistance Gene ◽  
Artemisinin Resistance ◽  
Chloroquine Resistance ◽  
Malaria Control Programme ◽  
Codon Substitution

Abstract Background Drug resistance is one of the greatest challenges of malaria control programme in Mali. Recent advances in next-generation sequencing (NGS) technologies provide new and effective ways of tracking drug-resistant malaria parasites in Africa. The diversity and the prevalence of Plasmodium falciparum drug-resistance molecular markers were assessed in Dangassa and Nioro-du-Sahel in Mali, two sites with distinct malaria transmission patterns. Dangassa has an intense seasonal malaria transmission, whereas Nioro-du-Sahel has an unstable and short seasonal malaria transmission. Methods Up to 270 dried blood spot samples (214 in Dangassa and 56 in Nioro-du-Sahel) were collected from P. falciparum positive patients in 2016. Samples were analysed on the Agena MassARRAY® iPLEX platform. Specific codons were targeted in Pfcrt, Pfmdr1, Pfdhfr, and Pfdhps, Pfarps10, Pfferredoxin, Pfexonuclease and Pfmdr2 genes. The Sanger’s 101-SNPs-barcode method was used to assess the genetic diversity of P. falciparum and to determine the parasite species. Results The Pfcrt_76T chloroquine-resistance genotype was found at a rate of 64.4% in Dangassa and 45.2% in Nioro-du-Sahel (p = 0.025). The Pfdhfr_51I-59R-108N pyrimethamine-resistance genotype was 14.1% and 19.6%, respectively in Dangassa and Nioro-du-Sahel. Mutations in the Pfdhps_S436-A437-K540-A581-613A sulfadoxine-resistance gene was significantly more prevalent in Dangassa as compared to Nioro-du-Sahel (p = 0.035). Up to 17.8% of the isolates from Dangassa vs 7% from Nioro-du-Sahel harboured at least two codon substitutions in this haplotype. The amodiaquine-resistance Pfmdr1_N86Y mutation was identified in only three samples (two in Dangassa and one in Nioro-du-Sahel). The lumefantrine-reduced susceptibility Pfmdr1_Y184F mutation was found in 39.9% and 48.2% of samples in Dangassa and Nioro-du-Sahel, respectively. One piperaquine-resistance Exo_E415G mutation was found in Dangassa, while no artemisinin resistance genetic-background were identified. A high P. falciparum diversity was observed, but no clear genetic aggregation was found at either study sites. Higher multiplicity of infection was observed in Dangassa with both COIL (p = 0.04) and Real McCOIL (p = 0.02) methods relative to Nioro-du-Sahel. Conclusions This study reveals high prevalence of chloroquine and pyrimethamine-resistance markers as well as high codon substitution rate in the sulfadoxine-resistance gene. High genetic diversity of P. falciparum was observed. These observations suggest that the use of artemisinins is relevant in both Dangassa and Nioro-du-Sahel.

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