scholarly journals No Polymorphism inPlasmodium falciparum K13Propeller Gene in Clinical Isolates from Kolkata, India

2015 ◽  
Vol 2015 ◽  
pp. 1-4 ◽  
Author(s):  
Moytrey Chatterjee ◽  
Swagata Ganguly ◽  
Pabitra Saha ◽  
Biswabandhu Bankura ◽  
Nandita Basu ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Molecular Markers ◽  
Artemisinin Resistance ◽  
Drug Regimen ◽  
Clinical Isolates ◽  
Wild Genotype ◽  
Emergence Of Resistance ◽  
Sulphadoxine Pyrimethamine

Molecular markers associated with artemisinin resistance inPlasmodium falciparumare yet to be well defined. Recent studies showed that polymorphisms inK13gene are associated with artemisinin resistance. The present study was designed to know the pattern of polymorphisms in propeller region ofK13gene among the clinical isolates collected from urban Kolkata after five years of ACT implementation. We collected 59 clinical isolates from urban Kolkata and sequenced propeller region ofK13gene in 51 isolates successfully. We did not find any mutation in any isolate. All patients responded to the ACT, a combination of artesunate + sulphadoxine-pyrimethamine. The drug regimen is still effective in the study area and there is no sign of emergence of resistance against artemisinin as evidenced by wild genotype ofK13gene in all isolates studied.

scholarly journals Plasmodium falciparum Malaria Parasites in Ghana Show Signatures of Balancing Selection at Artemisinin Resistance Predisposing Background Genes

2021 ◽  
Vol 17 ◽  
pp. 117693432199964
Author(s):  
Kwesi Z Tandoh ◽  
Lucas Amenga-Etego ◽  
Neils B Quashie ◽  
Gordon Awandare ◽  
Michael Wilson ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Molecular Markers ◽  
Falciparum Malaria ◽  
Early Warning ◽  
Balancing Selection ◽  
Artemisinin Resistance ◽  
Plasmodium Falciparum Malaria ◽  
Clinical Isolates ◽  
Malaria Parasites ◽  
Molecular Surveillance

Sub-Saharan Africa is courting the risk of artemisinin resistance (ARTr) emerging in Plasmodium falciparum malaria parasites. Current molecular surveillance efforts for ARTr have been built on the utility of P. falciparum kelch13 ( pfk13) validated molecular markers. However, whether these molecular markers will serve the purpose of early detection of artemisinin-resistant parasites in Ghana is hinged on a pfk13 dependent evolution. Here, we tested the hypothesis that the background pfk13 genome may be present before the pfk13 ARTr-conferring variant(s) is selected and that signatures of balancing selection on these genomic loci may serve as an early warning signal of ARTr. We analyzed 12 198 single nucleotide polymorphisms (SNPs) in Ghanaian clinical isolates in the Pf3K MalariaGEN dataset that passed a stringent filtering regimen. We identified signatures of balancing selection in 2 genes (phosphatidylinositol 4-kinase and chloroquine resistance transporter) previously reported as background loci for ARTr. These genes showed statistically significant and high positive values for Tajima’s D, Fu and Li’s F, and Fu and Li’s D. This indicates that the biodiversity required to establish a pfk13 background genome may have been primed in clinical isolates of P. falciparum from Ghana as of 2010. Despite the absence of ARTr in Ghana to date, our finding supports the current use of pfk13 for molecular surveillance of ARTr in Ghana and highlights the potential utility of monitoring malaria parasite populations for balancing selection in ARTr precursor background genes as early warning molecular signatures for the emergence of ARTr.

scholarly journals Surveillance of genetic markers associated with Plasmodium falciparum resistance to artemisinin-based combination therapy in Pakistan, 2018-2019

2020 ◽  
Author(s):  
Abdul Qader Khan ◽  
Leyre Pernaute-Lau ◽  
Aamer Ali Khattak ◽  
Sanna Luijcx ◽  
Berit Aydin-Schmidt ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Molecular Markers ◽  
Southeast Asia ◽  
Treatment Guidelines ◽  
Treatment Guideline ◽  
Artemisinin Resistance ◽  
Chloroquine Resistance ◽  
Close Monitoring ◽  
Malaria Surveillance ◽  
Current Prevalence

Abstract Background: The spread of artemisinin resistance in the Greater Mekong Subregion of Southeast Asia poses a significant threat for current anti-malarial treatment guidelines globally. The aim of this study was to assess the current prevalence of molecular markers of drug resistance in Plasmodium falciparum in the four provinces with the highest malaria burden in Pakistan, after introducing artemether-lumefantrine as first line treatment in 2017.Methods: Samples were collected during routine malaria surveillance in Punjab, Sindh, Baluchistan, and Khyber Pakhtunkhwa provinces of Pakistan between January 2018 and February 2019. P. falciparum infections were confirmed by rapid diagnostic test or microscopy. P. falciparum positive isolates (n = 179) were screened by Sanger sequencing for single nucleotide polymorphisms (SNPs) in the P. falciparum kelch 13 (pfk13) propeller domain and in P. falciparum coronin (pfcoronin). SNPs in P. falciparum multidrug resistance 1 (pfmdr1) N86Y, Y184F, D1246Y and P. falciparum chloroquine resistance transporter (pfcrt) K76T were genotyped by PCR-restriction fragment length polymorphism. Results: No artemisinin resistance associated SNPs were identified in the pfk13 propeller domain or in pfcoronin. The pfmdr1 N86, 184F, D1246 and pfcrt K76 alleles associated with reduced lumefantrine sensitivity were present in 83.8% (150/179), 16.9% (29/172), 100.0% (173/173), and 8.4% (15/179) of all infections, respectively. The chloroquine resistance associated pfcrt 76T allele was present in 98.3% (176/179) of infections.Conclusion: This study provides an update on the current prevalence of molecular markers associated with reduced sensitivity to artemether and/or lumefantrine in P. falciparum, including a first baseline assessment of polymorphisms in pfcoronin. No mutations associated with artemisinin resistance were observed in pfk13 or pfcoronin. However, the prevalence of the pfmdr1 N86 and D1246 alleles, that have been associated with decreased susceptibility to lumefantrine, remain high. Although clinical and molecular data suggest that the current malaria treatment guideline for P. falciparum are presently effective in Pakistan, close monitoring for artemisinin and lumefantrine resistance will be critical to ensure early detection and enhanced containment of emerging ACT resistance spreading across from Southeast Asia.

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 Detection of chloroquine and artemisinin resistance molecular markers in Plasmodium falciparum: A hospital based study

2016 ◽  
Vol 6 (1) ◽  
pp. 69 ◽  
Author(s):  
SubhashChandra Parija ◽  
S Ramani ◽  
Jharna Mandal ◽  
Abdoul Hamide ◽  
Vishnu Bhat
Keyword(s):  
Plasmodium Falciparum ◽  
Molecular Markers ◽  
Artemisinin Resistance

scholarly journals Clinical and in vitro resistance of Plasmodium falciparum to artesunate-amodiaquine in Cambodia

2020 ◽  
Author(s):  
Melissa Mairet-Khedim ◽  
Rithea Leang ◽  
Camille Marmai ◽  
Nimol Khim ◽  
Saorin Kim ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Molecular Markers ◽  
Falciparum Malaria ◽  
Artemisinin Resistance ◽  
Plasmodium Falciparum Malaria ◽  
Open Label ◽  
Parasite Survival ◽  
Adults And Children

Abstract Background Artesunate-amodiaquine is a potential therapy for uncomplicated malaria in Cambodia. Methods Between September 2016 and January 2017, artesunate-amodiaquine efficacy and safety were evaluated in a prospective, open-label, single-arm observational study at health centers in Mondulkiri, Pursat and Siem Reap Provinces, Cambodia. Adults and children with microscopically-confirmed Plasmodium falciparum malaria received oral artesunate-amodiaquine once daily for three days plus single-dose primaquine, with follow-up on Days 7, 14, 21 and 28. The primary outcome was Day-28 PCR-adjusted adequate clinical and parasitological response (ACPR). An amodiaquine parasite survival assay (AQSA) was developed and applied to whole genome sequencing results to evaluate potential amodiaquine resistance molecular markers. Results In 63 patients, Day-28 PCR-adjusted ACPR was 81.0% (95% confidence interval [CI], 68.9–88.7). Day 3 parasite positivity rate was 44.4% (28/63; 95%CI, 31.9–57.5). All 63 isolates had the K13(C580Y) marker for artemisinin resistance; 79.4% (50/63) had Pfpm2 amplification. The AQSA resistance phenotype (≥45% parasite survival) was expressed in 36.5% (23/63) of isolates and was significantly associated with treatment failure (P = 0.0020). Pfmdr1 mutant haplotypes were N86/184F/D1246 and Pfcrt was CVIET or CVIDT at positions 72–76. Additional Pfcrt mutations were not associated with amodiaquine resistance, but the G353V mutant allele was associated with ACPR compared to Pfmdr1 haplotypes harboring F1068L or S784L/R945P mutations (P = 0.030 and P = 0.0004, respectively). Conclusions For uncomplicated falciparum malaria in Cambodia, artesunate-amodiaquine had inadequate efficacy owing to amodiaquine-resistant P. falciparum. Amodiaquine resistance was not associated with previously identified molecular markers.

scholarly journals Genetic Architecture and Dynamics of PfKelch13’s Propeller Domain in Plasmodium Falciparum Clinical Isolates Collected in Senegal.

2021 ◽  
Author(s):  
Mariama Pouye ◽  
Gora Diop ◽  
celine Derbois ◽  
Babacar Mbengue ◽  
oumar Ka ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Artemisinin Resistance ◽  
Clinical Isolates ◽  
Health Concern ◽  
Gene Marker ◽  
Resistance Mutations ◽  
Malaria Epidemiology ◽  
Strategic Plans ◽  
Transmission Area

Abstract Plasmodium resistance to Artemisinin Combination-based Therapies (ACT) in Southeast Asia is a major public health concern that is sporadically appearing in Africa. Senegal has shifted from malaria control to elimination plans. Given notable progresses obtained through robust strategic plans, it is still crucial to assess genetic variability of the Plasmodium falciparum artemisinin resistance gene marker Kelch13 (PfKelch13) in circulating field isolates. We here report an analysis of PfKelch13-propeller polymorphism in clinical isolates collected nine years after ACT introduction in five Senegalese regions with different malaria transmission settings. Sequencing of PfKelch13-propeller domain from 280 clinical isolates reveals that 16% (45/280) of the parasite population harbored variants. Dynamics of PfKelch13 variants reveals emerging, persistent but also disappearing mutations over time. In addition to the malaria epidemiology, our survey also shows the dynamics of PfKelch13 variants in different malaria transmission settings in Senegal. Despite the absence of PfKelch13 associated artemisinin resistance mutations, a shift from 86% to 68% of PfKelch13WT was observed when comparing parasites collected prior vs. post ACT intensive usage in Dakar a low malaria transmission area. All together, our data confirms the need to closely monitor PfKelch13 polymorphism to anticipate and or prevent emergence of P. falciparum resistance in Senegal.

scholarly journals Monitoring of efficacy, tolerability and safety of artemether–lumefantrine and artesunate–amodiaquine for the treatment of uncomplicated Plasmodium falciparum malaria in Lambaréné, Gabon: an open-label clinical trial

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Bayode R. Adegbite ◽  
Jean R. Edoa ◽  
Yabo J. Honkpehedji ◽  
Frejus J. Zinsou ◽  
Jean C. Dejon-Agobe ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Drug Resistance ◽  
Plasmodium Falciparum ◽  
Molecular Markers ◽  
Uncomplicated Malaria ◽  
Artemisinin Resistance ◽  
Public Health Problem ◽  
World Health ◽  
Major Public Health Problem ◽  
Open Label

Abstract Background Malaria remains a major public health problem, affecting mainly low-and middle-income countries. The management of this parasitic disease is challenged by ever increasing drug resistance. This study, investigated the therapeutic efficacy, tolerability and safety of artemether–lumefantrine (AL) and artesunate–amodiaquine (AS–AQ), used as first-line drugs to treat uncomplicated malaria in Lambaréné, Gabon. Methods A non-randomized clinical trial was conducted between October 2017 and March 2018 to assess safety, clinical and parasitological efficacy of fixed-doses of AL and AS–AQ administered to treat uncomplicated Plasmodium falciparum malaria in children aged from 6 months to 12 years. After 50 children were treated with AL, another 50 children received ASAQ. The 2009 World Health Organization protocol for monitoring of the efficacy of anti‑malarial drugs was followed. Molecular markers msp1 and msp2 were used to differentiate recrudescence and reinfection. For the investigation of artemisinin resistant markers, gene mutations in Pfk13 were screened. Results Per-protocol analysis on day 28 showed a PCR corrected cure rate of 97% (95% CI 86–100) and 95% (95% CI 84–99) for AL and AS–AQ, respectively. The most frequent adverse event in both groups was asthenia. No mutations in the kelch-13 gene associated with artemisinin resistance were identified. All participants had completed microscopic parasite clearance by day 3 post-treatment. Conclusion This study showed that AL and AS–AQ remain efficacious, well-tolerated, and are safe to treat uncomplicated malaria in children from Lambaréné. However, a regular monitoring of efficacy and a study of molecular markers of drug resistance to artemisinin in field isolates is essential. Trial registration ANZCTR, ACTRN12616001600437. Registered 18 November, http://www.anzctr.org.au/TrialSearch.aspx?searchTxt=ACTRN12616001600437p&isBasic=True

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