scholarly journals Molecular surveillance of anti-malarial drug resistance in Democratic Republic of Congo: high variability of chloroquinoresistance and lack of amodiaquinoresistance

2020 ◽  
Author(s):  
Doudou M. Yobi ◽  
Nadine K. Kayiba ◽  
Dieudonné M. Mvumbi ◽  
Raphael Boreux ◽  
Pius Z. Kabututu ◽  
...  
Keyword(s):  
Continuous Monitoring ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Gene Segment ◽  
Resistance Marker ◽  
Pcr Assay ◽  
Resistance Level ◽  
Molecular Surveillance ◽  
Republic Of Congo ◽  
Species Specific

Abstract Background: The loss of chloroquine (CQ) effectiveness has led to its withdrawal from national policies as a first-line treatment for uncomplicated malaria in several endemic countries, such as the Democratic Republic of Congo (DRC). The K76T mutation on the pfcrt gene has been identified as a marker of CQ resistance and the SVMNT haplotype in codons 72–76 on the same gene has been associated with resistance to amodiaquine (AQ). In the DRC, the prevalence of K76T has decreased from 100% in 2000 to 63.9% in 2014. The purpose of this study was to determine the prevalence of K76T mutations in circulating strains of Plasmodium falciparum, sixteen years after CQ withdrawal in the DRC and to investigate the presence of the SVMNT haplotype. Methods : In 2017, ten geographical sites across the DRC were selected. Dried blood samples were collected from patients attending health centres. Malaria was first detected by a rapid diagnostic test (RDT) available on site (SD Bioline Malaria Ag Pf or CareStart Malaria Pf) or thick blood smear and then confirmed by a P. falciparum species-specific real-time PCR assay. A pfcrt gene segment containing a fragment that encodes amino acids at positions 72-76 was amplified by conventional PCR before sequencing. Results: A total of 1070 patients were enrolled. Of the 806 PCR-confirmed P. falciparum positive samples, 764 were successfully sequenced. The K76T mutation was detected in 218 samples (28.5%; 95% CI: 25.4%–31.9%), mainly (96%) with the CVIET haplotype. Prevalence of CQ resistance marker was unequally distributed across the country, ranging from 1.5% in Fungurume to 89.5% in Katana. The SVMNT haplotype, related to AQ resistance, was not detected. Conclusion: Overall, the frequency of the P. falciparum CQ resistance marker has decreased significantly and no resistance marker to AQ was detected in the DRC in 2017. However, the between regions variability of CQ resistance remains high in the country. Further studies are needed for continuous monitoring of the CQ resistance level for its prospective re-use in malaria management. The absence of the AQ resistance marker is in line with the use of this drug in the current DRC malaria treatment policy.

scholarly journals Molecular surveillance of antimalarial drug resistance in Democratic Republic of Congo: high variability of chloroquinoresistance and lack of amodiaquinoresistance

2020 ◽  
Author(s):  
Doudou Malekita Yobi ◽  
Nadine Kalenda Kayiba ◽  
Dieudonné Makaba Mvumbi ◽  
Raphael Boreux ◽  
Pius Zakayi Kabututu ◽  
...  
Keyword(s):  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Gene Segment ◽  
Resistance Marker ◽  
Antimalarial Drug Resistance ◽  
Resistance Level ◽  
Molecular Surveillance ◽  
Republic Of Congo ◽  
Pfcrt Gene ◽  
Species Specific

Abstract Background The loss of chloroquine (CQ) effectiveness has led to its withdrawal from national policies as first-line treatment for uncomplicated malaria in several endemic countries such as in the Democratic Republic of Congo (DRC). The K76T mutation on the pfcrt gene has been identified as a marker of CQ resistance and the SVMNT haplotype in codons 72–76 on the same gene has been associated with resistance to amodiaquine (AQ). In DRC, the prevalence of K76T has decreased from 100% in 2000 to 63.9% in 2014. The purpose of the study was to determine the prevalence of K76T mutations in P. falciparum circulating strains, sixteen years after CQ withdrawal in DRC and to investigate the presence of SVMNT haplotype. Methods In 2017, ten geographical sites across DRC were selected. Dried blood samples were collected from patients attending health centers. Malaria was first detected by rapid diagnostic test (RDT) available on site (SD Bioline malaria Ag Pf or CareStart Malaria Pf) or thick blood smear and then confirmed by a P. falciparum species-specific real-time PCR assay. A pfcrt gene segment containing a fragment that encodes amino acids at positions 72-76 was amplified by conventional PCR before sequencing. Results A total of 1070 patients were enrolled. Of the 806 PCR-confirmed P. falciparum positive samples, 764 were successfully sequenced. The K76T mutation was detected in 218 (28.5%; 95% CI: 25.4% – 31.9%) samples, mainly (96%) with the CVIET haplotype. The CQ resistance prevalence was unequally distributed across the country ranging from 1.5% in Fungurume to 89.5% in Katana. The SVMNT haplotype, related to AQ resistance, was not detected. Conclusion Overall, the frequency of P. falciparum CQ resistance marker has decreased significantly and no resistance marker to AQ was detected in DRC in 2017. However, the between regions variability of CQ resistance remains high in the country. Further studies are needed for a continuous monitoring of the CQ resistance level for a prospective re-use in malaria management. The absence of AQ resistance is in line with the use of this drug in the current DRC malaria treatment policy.

scholarly journals Molecular surveillance of antimalarial drug resistance in the Democratic Republic of Congo: high variability of chloroquinoresistance and lack of amodiaquinoresistance

2020 ◽  
Author(s):  
Doudou Malekita Yobi ◽  
Nadine Kalenda Kayiba ◽  
Dieudonné Makaba Mvumbi ◽  
Raphael Boreux ◽  
Pius Zakayi Kabututu ◽  
...  
Keyword(s):  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Gene Segment ◽  
Resistance Marker ◽  
Antimalarial Drug Resistance ◽  
Resistance Level ◽  
Molecular Surveillance ◽  
Republic Of Congo ◽  
Pfcrt Gene ◽  
Species Specific

Abstract Background The loss of chloroquine (CQ) effectiveness has led to its withdrawal from national policies as a first-line treatment for uncomplicated malaria in several endemic countries, such as the Democratic Republic of Congo (DRC). The K76T mutation on the pfcrt gene has been identified as a marker of CQ resistance and the SVMNT haplotype in codons 72–76 on the same gene has been associated with resistance to amodiaquine (AQ). In the DRC, the prevalence of K76T has decreased from 100% in 2000 to 63.9% in 2014. The purpose of this study was to determine the prevalence of K76T mutations in circulating strains of P. falciparum , sixteen years after CQ withdrawal in the DRC and to investigate the presence of the SVMNT haplotype. Methods In 2017, ten geographical sites across the DRC were selected. Dried blood samples were collected from patients attending health centres. Malaria was first detected by a rapid diagnostic test (RDT) available on site (SD Bioline Malaria Ag P.f or CareStart Malaria Pf ) or thick blood smear and then confirmed by a P. falciparum species-specific real-time PCR assay. A pfcrt gene segment containing a fragment that encodes amino acids at positions 72-76 was amplified by conventional PCR before sequencing. Results A total of 1070 patients were enrolled. Of the 806 PCR-confirmed P. falciparum positive samples, 764 were successfully sequenced. The K76T mutation was detected in 218 samples (28.5%; 95% CI: 25.4%–31.9%), mainly (96%) with the CVIET haplotype. Prevalence of CQ resistance marker was unequally distributed across the country, ranging from 1.5% in Fungurume to 89.5% in Katana. The SVMNT haplotype, related to AQ resistance, was not detected. Conclusion Overall, the frequency of the P. falciparum CQ resistance marker has decreased significantly and no resistance marker to AQ was detected in the DRC in 2017. However, the between regions variability of CQ resistance remains high in the country. Further studies are needed for continuous monitoring of the CQ resistance level for its prospective re-use in malaria management. The absence of the AQ resistance marker is in line with the use of this drug in the current DRC malaria treatment policy.

scholarly journals Molecular surveillance of antimalarial drug resistance in Democratic Republic of Congo: high variability of chloroquinoresistance and lack of amodiaquinoresistance

2019 ◽  
Author(s):  
Doudou Malekita Yobi ◽  
Nadine Kalenda Kayiba ◽  
Dieudonné Makaba Mvumbi ◽  
Raphael Boreux ◽  
Pius Zakayi Kabututu ◽  
...  
Keyword(s):  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Gene Segment ◽  
Resistance Rate ◽  
Antimalarial Drug Resistance ◽  
Resistance Level ◽  
Molecular Surveillance ◽  
Republic Of Congo ◽  
Pfcrt Gene ◽  
Species Specific

Abstract Background The loss of chloroquine (CQ) effectiveness has led to its withdrawal from national policies as first-line treatment for uncomplicated malaria in several endemic countries such as in the Democratic Republic of Congo (DRC). The K76T mutation on the pfcrt gene has been identified as a marker of CQ resistance and the SVMNT haplotype in codons 72–76 on the same gene has been associated with resistance to amodiaquine (AQ). In DRC, the prevalence of K76T has decreased from 100% in 2000 to 63.9% in 2014. The purpose of the study was to determine the prevalence of K76T mutations in P. falciparum circulating strains, sixteen years after CQ withdrawal in DRC and to investigate the presence of SVMNT haplotype. Methods In 2017, ten geographical sites across DRC were selected. Dried blood samples were collected from patients attending health centers. Malaria was first detected by rapid diagnostic test (RDT) available on site (SD Bioline malaria Ag Pf or CareStart Malaria Pf) or thick blood smear and then confirmed by a P. falciparum species-specific real-time PCR assay. A pfcrt gene segment containing a fragment that encodes amino acids at positions 72-76 was amplified by conventional PCR before sequencing. Results A total of 1070 patients were enrolled. Of the 806 PCR-confirmed P. falciparum positive samples, 764 were successfully sequenced. The K76T mutation was detected in 218 (28.5%; IC95%: 25.4% – 31.9%) samples, mainly (96%) with the CVIET haplotype. The CQ resistance prevalence was unequally distributed across the country ranging from 1.5% in Fungurume to 89.5% in Katana. The SVMNT haplotype, related to AQ resistance, was not detected. Conclusion Overall, the P. falciparum CQ resistance rate has decreased significantly and no resistance marker to AQ was detected in DRC in 2017. However, the between regions variability of CQ resistance remains high in the country. Further studies are needed for a continuous monitoring of the CQ resistance level for a prospective re-use in malaria management. The absence of AQ resistance is in line with the use of this drug in the current DRC malaria treatment policy.

scholarly journals Molecular surveillance of Plasmodium falciparum resistance to artemisinin-based combination therapies in the Democratic Republic of Congo

PLoS ONE ◽  
2017 ◽  
Vol 12 (6) ◽  
pp. e0179142 ◽  
Author(s):  
Dieudonné Makaba Mvumbi ◽  
Thierry Lengu Bobanga ◽  
Jean-Marie Ntumba Kayembe ◽  
Georges Lelo Mvumbi ◽  
Hippolyte Nani-Tuma Situakibanza ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Combination Therapies ◽  
Molecular Surveillance ◽  
Republic Of Congo

scholarly journals Assessment of Molecular Markers of Anti-malarial Drug Resistance in Pfk13-propeller, Pfcrt and Pfmdr1 Genes in Plasmodium Falciparum Isolated From Patients Returning for Malaria Retreatment in Democratic Republic of Congo 

2020 ◽  
Author(s):  
Doudou Malekita Yobi ◽  
Nadine K. Kayiba ◽  
Dieudonné M. Mvumbi ◽  
Raphael Boreux ◽  
Pius Z. Kabututu ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Molecular Markers ◽  
Real Time ◽  
Real Time Pcr ◽  
Copy Number ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
First Line ◽  
Pcr Assay ◽  
Republic Of Congo

Abstract BackgroundThe Democratic Republic of Congo (DRC) malaria treatment policy recommends two first-line artemisinin-based combination therapies (ACTs) for the treatment of uncomplicated malaria: Artesunate-amodiaquine (ASAQ) and Artemether-lumefantrine (AL). This study investigated resistance to the ACTs currently in use in DRC through molecular markers in pfk13, pfcrt and pfmdr1 genes in Plasmodium falciparum isolated from patients returning for malaria retreatment. MethodsFrom November 2018 to November 2019, dried blood spots were taken from patients returning to health structures for fever within 28 days after an initial malaria treatment in 6 sentinel sites of National Malaria Control Programme (NMCP) across DRC. The new episode of malaria was first detected by a rapid diagnostic test (RDT) and then confirmed by a real-time PCR assay. Fragments of interest in pfk13 and pfcrt genes were amplified by conventional PCR before sequencing and Pfmdr1 gene copy number was determined by a TaqMan real-time PCR assay. ResultsOut of 474 enrolled patients, 364 (76.8%) were confirmed positive by PCR for P. falciparum. Of the 325 P. falciparum isolates successfully sequenced in pfk13-propeller gene, 7 (2.2%) carried non-synonymous (NS) mutations among which 3 previously reported (N498I, N554K and A557S) and 4 not yet reported (F506L, E507V, D516E and G538S). Of the 335 isolates successfully sequenced in pfcrt gene, 139 (41.5%) harbored the K76T mutation known to be associated with CQ resistance. The SVMNT haplotype associated with resistance to AQ has not been found. None of the isolates carried increased copy number of pfmdr1 gene among the 322 P. falciparum isolates successfully analyzed.ConclusionNo molecular marker known to date as associated with resistance to first-line ACTs in use was detected in P. falciparum isolated in patients returning for retreatment. Regular monitoring through in vivo drug efficacy and molecular studies must continue to ensure the effectiveness of the treatment of malaria in DRC.

scholarly journals Assessment of Plasmodium falciparum anti-malarial drug resistance markers in pfk13-propeller, pfcrt and pfmdr1 genes in isolates from treatment failure patients in Democratic Republic of Congo, 2018–2019

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Doudou M. Yobi ◽  
Nadine K. Kayiba ◽  
Dieudonné M. Mvumbi ◽  
Raphael Boreux ◽  
Pius Z. Kabututu ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Treatment Failure ◽  
Real Time Pcr ◽  
Copy Number ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Malaria Treatment ◽  
First Line ◽  
Pcr Assay ◽  
Republic Of Congo

Abstract Background The national policy for malaria treatment of the Democratic Republic of Congo recommends two first-line artemisinin-based combinations for the treatment of uncomplicated malaria: artesunate-amodiaquine and artemether-lumefantrine. This study investigated the presence of markers associated with resistance to the current first-line artemisinin-based combination therapy (ACT) in isolates of Plasmodium falciparum from treatment failure patients in the Democratic Republic of Congo. Methods From November 2018 to November 2019, dried blood spots were taken from patients returning to health centres for fever within 28 days after an initial malaria treatment in six sentinel sites of the National Malaria Control Programme across Democratic Republic of Congo. The new episode of malaria was first detected by a rapid diagnostic test and then confirmed by a real-time PCR assay to define treatment failure. Fragments of interest in pfk13 and pfcrt genes were amplified by conventional PCR before sequencing and the Pfmdr1 gene copy number was determined by a TaqMan real-time PCR assay. Results Out of 474 enrolled patients, 364 (76.8%) were confirmed positive by PCR for a new episode of P. falciparum malaria, thus considered as treatment failure. Of the 325 P. falciparum isolates obtained from 364 P. falciparum-positive patients and successfully sequenced in the pfk13-propeller gene, 7 (2.2%) isolates carried non-synonymous mutations, among which 3 have been previously reported (N498I, N554K and A557S) and 4 had not yet been reported (F506L, E507V, D516E and G538S). Of the 335 isolates successfully sequenced in the pfcrt gene, 139 (41.5%) harboured the K76T mutation known to be associated with chloroquine resistance. The SVMNT haplotype associated with resistance to amodiaquine was not found. None of the isolates carried an increased copy number of the pfmdr1 gene among the 322 P. falciparum isolates successfully analysed. Conclusion No molecular markers currently known to be associated with resistance to the first-line ACT in use were detected in isolates of P. falciparum from treatment failure patients. Regular monitoring through in vivo drug efficacy and molecular studies must continue to ensure the effectiveness of malaria treatment in Democratic Republic of Congo.

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