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Wu Y, Soe MT, Aung PL, Zhao L, Zeng W, Menezes L, Yang Z, Kyaw MP, Cui L. Efficacy of artemether-lumefantrine for treating uncomplicated Plasmodium falciparum cases and molecular surveillance of drug resistance genes in Western Myanmar. Malar J 2020; 19:304. [PMID: 32854686 PMCID: PMC7450958 DOI: 10.1186/s12936-020-03376-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 08/14/2020] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Currently, artemisinin-based combination therapy (ACT) is the first-line anti-malarial treatment in malaria-endemic areas. However, resistance in Plasmodium falciparum to artemisinin-based combinations emerging in the Greater Mekong Sub-region is a major problem hindering malaria elimination. To continuously monitor the potential spread of ACT-resistant parasites, this study assessed the efficacy of artemether-lumefantrine (AL) for falciparum malaria in western Myanmar. METHODS Ninety-five patients with malaria symptoms from Paletwa Township, Chin State, Myanmar were screened for P. falciparum infections in 2015. After excluding six patients with a parasite density below 100 or over 150,000/µL, 41 P. falciparum patients were treated with AL and followed for 28 days. Molecular markers associated with resistance to 4-amino-quinoline drugs (pfcrt and pfmdr1), antifolate drugs (pfdhps and pfdhfr) and artemisinin (pfk13) were genotyped to determine the prevalence of mutations associated with anti-malarial drug resistance. RESULTS For the 41 P. falciparum patients (27 children and 14 adults), the 28-day AL therapeutic efficacy was 100%, but five cases (12.2%) were parasite positive on day 3 by microscopy. For the pfk13 gene, the frequency of NN insert after the position 136 was 100% in the day-3 parasite-positive group as compared to 50.0% in the day-3 parasite-negative group, albeit the difference was not statistically significant (P = 0.113). The pfk13 K189T mutation (10.0%) was found in Myanmar for the first time. The pfcrt K76T and A220S mutations were all fixed in the parasite population. In pfmdr1, the Y184F mutation was present in 23.3% of the parasite population, and found in both day-3 parasite-positive and -negative parasites. The G968A mutation of pfmdr1 gene was first reported in Myanmar. Prevalence of all the mutations in pfdhfr and pfdhps genes assessed was over 70%, with the exception of the pfdhps A581G mutation, which was 3.3%. CONCLUSIONS AL remained highly efficacious in western Myanmar. Pfk13 mutations associated with artemisinin resistance were not found. The high prevalence of mutations in pfcrt, pfdhfr and pfdhps suggests high-degree resistance to chloroquine and antifolate drugs. The pfmdr1 N86/184F/D1246 haplotype associated with selection by AL in Africa reached > 20% in this study. The detection of > 10% patients who were day-3 parasite-positive after AL treatment emphasizes the necessity of continuously monitoring ACT efficacy in western Myanmar.
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Affiliation(s)
- Yanrui Wu
- Department of Cell Biology & Genetics, Kunming Medical University, Kunming, China
| | - Myat Thut Soe
- Myanmar Health Network Organization, Yangon, Myanmar
| | | | - Luyi Zhao
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Weilin Zeng
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Lynette Menezes
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China.
| | - Myat Phone Kyaw
- Myanmar Health Network Organization, Yangon, Myanmar.
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China.
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
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Pathak A, Mårtensson A, Gawariker S, Sharma A, Diwan V, Purohit M, Ursing J. Stable high frequencies of sulfadoxine-pyrimethamine resistance associated mutations and absence of K13 mutations in Plasmodium falciparum 3 and 4 years after the introduction of artesunate plus sulfadoxine-pyrimethamine in Ujjain, Madhya Pradesh, India. Malar J 2020; 19:290. [PMID: 32795288 PMCID: PMC7427725 DOI: 10.1186/s12936-020-03274-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 05/29/2020] [Indexed: 11/27/2022] Open
Abstract
Background Artesunate plus sulfadoxine–pyrimethamine (ASP) is first-line treatment for uncomplicated Plasmodium falciparum malaria in most of India, except for six North-eastern provinces where treatment failure rates were high. In Ujjain, central India, the frequency of mutations associated with increased drug tolerance, but not overt resistance to sulfadoxine and pyrimethamine were 9% and > 80%, respectively, in 2009 and 2010, just prior to the introduction of ASP. The frequency of drug resistance associated mutations in Ujjain in 2015–2016 after 3–4 years of ASP use, are reported. Methods Blood samples from patients with P. falciparum mono-infection verified by microscopy were collected on filter-paper at all nine major pathology laboratories in Ujjain city. Codons pfdhfr 16–185, pfdhps 436–632 and K13 407–689 were identified by sequencing. Pfcrt K76T and pfmdr1 N86Y were identified by restriction fragment length polymorphism. Results Sulfadoxine–pyrimethamine resistance-associated pfdhfr 108 N and 59R alleles were found in 100/104 (96%) and 87/91 (96%) samples, respectively. Pfdhps 437G was found in 10/105 (10%) samples. Double mutant pfdhfr 59R + 108 N were found in 75/81 (93%) samples. Triple mutant pfdhfr 59R + 108 N and pfdhps 437G were found in 6/78 (8%) samples. Chloroquine-resistance-associated pfcrt 76T was found in 102/102 (100%). Pfmdr1 N86 and 86Y were identified in 83/115 (72%) and 32/115 (28%) samples, respectively. Conclusion The frequency of P. falciparum with reduced susceptibility to sulfadoxine–pyrimethamine remained high, but did not appear to have increased significantly since the introduction of ASP. No polymorphisms in K13 associated with decreased artemisinin susceptibility were found. ASP probably remained effective, supporting continued ASP use.
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Affiliation(s)
- Ashish Pathak
- Department of Pediatrics, R D Gardi Medical College, Surasa, 456010, Ujjain, India.,Department of Women and Children's Health, International Maternal and Child Health Unit, Uppsala University, 751 85, Uppsala, Sweden.,Global Health-Health Systems and Policy: Medicines, Focusing Antibiotics, Department of Global Public Health, Karolinska Institutet, Tomtebodavägen 18A, 171 77, Stockholm, Sweden
| | - Andreas Mårtensson
- Department of Women and Children's Health, International Maternal and Child Health Unit, Uppsala University, 751 85, Uppsala, Sweden
| | - Sudhir Gawariker
- Department of Medicine, R D Gardi Medical College, Surasa, 456010, Ujjain, India
| | - Ashish Sharma
- Department of Medicine, R D Gardi Medical College, Surasa, 456010, Ujjain, India
| | - Vishal Diwan
- Department of Women and Children's Health, International Maternal and Child Health Unit, Uppsala University, 751 85, Uppsala, Sweden.,Public Health & Environment in R D Gardi Medical College, Ujjain, India
| | - Manju Purohit
- Global Health-Health Systems and Policy: Medicines, Focusing Antibiotics, Department of Global Public Health, Karolinska Institutet, Tomtebodavägen 18A, 171 77, Stockholm, Sweden.,Department of Pathology, R D Gardi Medical College, Surasa, 456010, Ujjain, India
| | - Johan Ursing
- Department of Infectious Diseases, Danderyd Hospital, Stockholm, Sweden. .,Department of Clinical Sciences, Karolinska Institutet, Danderyd Hospital, Stockholm, Sweden.
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Tornyigah B, Coppée R, Houze P, Kusi KA, Adu B, Quakyi I, Coleman N, Mama A, Deloron P, Anang AK, Clain J, Tahar R, Ofori MF, Tuikue Ndam N. Effect of Drug Pressure on Promoting the Emergence of Antimalarial-Resistant Parasites among Pregnant Women in Ghana. Antimicrob Agents Chemother 2020; 64:e02029-19. [PMID: 32179528 DOI: 10.1128/AAC.02029-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 03/08/2020] [Indexed: 11/20/2022] Open
Abstract
The continuous spread of antimalarial drug resistance is a threat to current chemotherapy efficacy. Therefore, characterizing the genetic diversity of drug resistance markers is needed to follow treatment effectiveness and further update control strategies. Here, we genotyped Plasmodium falciparum resistance gene markers associated with sulfadoxine-pyrimethamine (SP) and artemisinin-based combination therapy (ACT) in isolates from pregnant women in Ghana. The prevalence of the septuple IRN I- A/FG K GS/T pfdhfr/pfdhps haplotypes, including the pfdhps A581G and A613S/T mutations, was high at delivery among post-SP treatment isolates (18.2%) compared to those of first antenatal care (before initiation of intermittent preventive treatment of malaria in pregnancy with sulfadoxine-pyrimethamine [IPTp-SP]; 6.1%; P = 0.03). Regarding the pfk13 marker gene, two nonsynonymous mutations (N458D and A481C) were detected at positions previously related to artemisinin resistance in isolates from Southeast Asia. These mutations were predicted in silico to alter the stability of the pfk13 propeller-encoding domain. Overall, these findings highlight the need for intensified monitoring and surveillance of additional mutations associated with increased SP resistance as well as emergence of resistance against artemisinin derivatives.
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Sugaram R, Suwannasin K, Kunasol C, Mathema VB, Day NPJ, Sudathip P, Prempree P, Dondorp AM, Imwong M. Molecular characterization of Plasmodium falciparum antifolate resistance markers in Thailand between 2008 and 2016. Malar J 2020; 19:107. [PMID: 32127009 PMCID: PMC7055081 DOI: 10.1186/s12936-020-03176-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/22/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Resistance to anti-malarials is a major threat to the control and elimination of malaria. Sulfadoxine-pyrimethamine (SP) anti-malarial treatment was used as a national policy for treatment of uncomplicated falciparum malaria in Thailand from 1973 to 1990. In order to determine whether withdrawal of this antifolate drug has led to restoration of SP sensitivity, the prevalence of genetic markers of SP resistance was assessed in historical Thai samples. METHODS Plasmodium falciparum DNA was collected from the Thailand-Myanmar, Thailand-Malaysia and Thailand-Cambodia borders during 2008-2016 (N = 233). Semi-nested PCR and nucleotide sequencing were used to assess mutations in Plasmodium falciparum dihydrofolate reductase (pfdhfr), P. falciparum dihydropteroate synthase (pfdhps). Gene amplification of Plasmodium falcipaurm GTP cyclohydrolase-1 (pfgch1) was assessed by quantitative real-time PCR. The association between pfdhfr/pfdhps mutations and pfgch1 copy numbers were evaluated. RESULTS Mutations in pfdhfr/pfdhsp and pfgch1 copy number fluctuated overtime through the study period. Altogether, 14 unique pfdhfr-pdfhps haplotypes collectively containing quadruple to octuple mutations were identified. High variation in pfdhfr-pfdhps haplotypes and a high proportion of pfgch1 multiple copy number (51% (73/146)) were observed on the Thailand-Myanmar border compared to other parts of Thailand. Overall, the prevalence of septuple mutations was observed for pfdhfr-pfdhps haplotypes. In particular, the prevalence of pfdhfr-pfdhps, septuple mutation was observed in the Thailand-Myanmar (50%, 73/146) and Thailand-Cambodia (65%, 26/40) border. In Thailand-Malaysia border, majority of the pfdhfr-pfdhps haplotypes transaction from quadruple (90%, 9/10) to quintuple (65%, 24/37) during 2008-2016. Within the pfdhfr-pfdhps haplotypes, during 2008-2013 the pfdhps A/S436F mutation was observed only in Thailand-Myanmar border (9%, 10/107), while it was not identified later. In general, significant correlation was observed between the prevalence of pfdhfr I164L (ϕ = 0.213, p-value = 0.001) or pfdhps K540E/N (ϕ = 0.399, p-value ≤ 0.001) mutations and pfgch1 gene amplification. CONCLUSIONS Despite withdrawal of SP as anti-malarial treatment for 17 years, the border regions of Thailand continue to display high prevalence of antifolate and anti-sulfonamide resistance markers in falciparum malaria. Significant association between pfgch1 amplification and pfdhfr (I164L) or pfdhps (K540E) resistance markers were observed, suggesting a compensatory mutation.
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Affiliation(s)
- Rungniran Sugaram
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd., Bangkok, 10400, Thailand
- Division of Vector Borne Diseases, Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand
| | - Kanokon Suwannasin
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Chanon Kunasol
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Vivek Bhakta Mathema
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nicholas P J Day
- Division of Vector Borne Diseases, Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand
- Centre for Tropical Medicine, Churchill Hospital, Oxford, UK
| | - Prayuth Sudathip
- Division of Vector Borne Diseases, Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand
| | - Preecha Prempree
- Division of Vector Borne Diseases, Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand
| | - Arjen M Dondorp
- Division of Vector Borne Diseases, Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand
- Centre for Tropical Medicine, Churchill Hospital, Oxford, UK
| | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd., Bangkok, 10400, Thailand.
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Smith-Aguasca R, Gupta H, Uberegui E, Maquina M, Saute F, Paaijmans KP, Mayor A, Huijben S. Mosquitoes as a feasible sentinel group for anti-malarial resistance surveillance by Next Generation Sequencing of Plasmodium falciparum. Malar J 2019; 18:351. [PMID: 31623623 PMCID: PMC6796398 DOI: 10.1186/s12936-019-2946-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 09/03/2019] [Indexed: 12/19/2022] Open
Abstract
Background Plasmodium falciparum drug resistance surveillance is key to successful disease control and eradication. Contemporary methods that only allow determination of prevalence of resistance are expensive, time consuming and require ethical considerations. A newer method involving Next Generation Sequencing (NGS) permits obtaining frequency of resistance while allowing to detect minority variants in mixed infections. Here, NGS was tested for P. falciparum resistance marker detection in mosquito samples as a feasible and suitable alternative for molecular resistance surveillance. Anopheles funestus were collected in southern Mozambique using CDC light traps and manual collections. DNA was extracted from either whole mosquito, head-thorax and abdomen separately or pools of five mosquitoes. These samples were screened for P. falciparum and if positive for k13, pfcrt, pfmdr1, pfdhps and pfdhfr mutations related to anti-malarial drug resistance with Sanger sequencing and NGS. Results Among the 846 samples screened for P. falciparum, 122 were positive by 18S ssrDNA qPCR with an infection rate of 23.6%. No mutations were observed for k13 and pfcrt72-76 and almost zero for pfmdr86, but quintuple pfdhfr/pfdhps mutations were near fixation and about half of the isolates contained the pfmdr184F polymorphism. Similar allele frequencies of resistance markers were estimated with NGS in comparison with the prevalence of markers obtained with the gold standard Sanger sequencing. Conclusions Pooled deep sequencing of P. falciparum isolates extracted from mosquitoes is a promising, efficient and cost-effective method to quantify allele frequencies at population level which allows to detect known and unknown markers of resistance in single and mixed infections in a timelier manner. Using mosquitoes as sentinel group and focusing on allele frequency opposed to prevalence, permits active surveillance across a more homogeneous geographical range.
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Affiliation(s)
- Rebecca Smith-Aguasca
- ISGlobal, Hospital Clínic - Universitat de Barcelona, 08036, Barcelona, Spain.,Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ, 85287-1701, USA
| | - Himanshu Gupta
- ISGlobal, Hospital Clínic - Universitat de Barcelona, 08036, Barcelona, Spain
| | - Estefania Uberegui
- ISGlobal, Hospital Clínic - Universitat de Barcelona, 08036, Barcelona, Spain
| | - Mara Maquina
- Centro de Investigação em Saúde da Manhiça (CISM), 1929, Manhiça, Mozambique
| | - Francisco Saute
- Centro de Investigação em Saúde da Manhiça (CISM), 1929, Manhiça, Mozambique
| | - Krijn P Paaijmans
- ISGlobal, Hospital Clínic - Universitat de Barcelona, 08036, Barcelona, Spain.,Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ, 85287-1701, USA.,Centro de Investigação em Saúde da Manhiça (CISM), 1929, Manhiça, Mozambique.,The Biodesign Center for Immunotherapy, Vaccines and Virotherapy, Arizona State University, Tempe, AZ, 85287-1701, USA
| | - Alfredo Mayor
- ISGlobal, Hospital Clínic - Universitat de Barcelona, 08036, Barcelona, Spain.,Centro de Investigação em Saúde da Manhiça (CISM), 1929, Manhiça, Mozambique
| | - Silvie Huijben
- ISGlobal, Hospital Clínic - Universitat de Barcelona, 08036, Barcelona, Spain. .,Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ, 85287-1701, USA.
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Zhou R, Yang C, Li S, Zhao Y, Liu Y, Qian D, Wang H, Lu D, Zhang H, Huang F. Molecular Surveillance of Drug Resistance of Plasmodium falciparum Isolates Imported from Angola in Henan Province, China. Antimicrob Agents Chemother 2019; 63:e00552-19. [PMID: 31358591 DOI: 10.1128/AAC.00552-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 07/22/2019] [Indexed: 11/20/2022] Open
Abstract
Angola was the main origin country for the imported malaria in Henan Province, China. Antimalarial drug resistance has posed a threat to the control and elimination of malaria. Several molecular markers were confirmed to be associated with the antimalarial drug resistance, such as pfcrt, pfmdr1, pfdhfr, pfdhps, and K13. This study evaluated the drug resistance of the 180 imported Plasmodium falciparum isolates from Angola via nested PCR using Sanger sequencing. The prevalences of pfcrt C72V73M74N75K76, pfmdr1 N86Y184S1034N1042D1246, pfdhfr A16N51C59S108D139I164, and pfdhps S436A437A476K540A581 were 69.4%, 59.9%, 1.3% and 6.3%, respectively. Three nonsynonymous (A578S, M579I, and Q613E) and one synonymous (R471R) mutation of K13 were found, the prevalences of which were 2.5% and 1.3%, respectively. The single nucleotide polymorphisms (SNPs) in pfcrt, pfmdr1, pfdhfr, and pfdhps were generally shown as multiple mutations. The mutant prevalence of pfcrt reduced gradually, but pfdhfr and pfdhps still showed high mutant prevalence, while pfmdr1 was relatively low. The mutation of the K13 gene was rare. Molecular surveillance of artemisinin (ART) resistance will be used as a tool to evaluate the real-time efficacy of the artemisinin-based combination therapies (ACTs) and the ART resistance situation.
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Nag S, Ursing J, Rodrigues A, Crespo M, Krogsgaard C, Lund O, Aarestrup FM, Alifrangis M, Kofoed PE. Proof of concept: used malaria rapid diagnostic tests applied for parallel sequencing for surveillance of molecular markers of anti-malarial resistance in Bissau, Guinea-Bissau during 2014-2017. Malar J 2019; 18:252. [PMID: 31349834 DOI: 10.1186/s12936-019-2894-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 07/23/2019] [Indexed: 01/17/2023] Open
Abstract
Background Large-scale surveillance of molecular markers of anti-malarial drug resistance is an attractive method of resistance monitoring, to complement therapeutic efficacy studies in settings where the latter are logistically challenging. Methods Between 2014 and 2017, this study sampled malaria rapid diagnostic tests (RDTs), used in routine clinical care, from two health centres in Bissau, Guinea-Bissau. In order to obtain epidemiological insights, RDTs were collected together with patient data on age and sex. A subset of positive RDTs from one of the two sites (n = 2184) were tested for Plasmodium DNA content. Those testing positive for Plasmodium DNA by PCR (n = 1390) were used for library preparation, custom designed dual indexing and next generation Miseq targeted sequencing of Plasmodium falciparum genes pfcrt, pfmdr1, pfdhfr, pfdhps and pfk13. Results The study found a high frequency of the pfmdr1 codon 86N at 88–97%, a significant decrease of the pfcrt wildtype CVMNK haplotype and elevated levels of the pfdhfr/pfdhps quadruple mutant ranging from 33 to 51% between 2014 and 2017. No polymorphisms indicating artemisinin tolerance were discovered. The demographic data indicate a large proportion of young adults (66%, interquartile range 11–28 years) presenting with P. falciparum infections. While a total of 5532 gene fragments were successfully analysed on a single Illumina Miseq flow cell, PCR-positivity from the library preparation varied considerably from 13 to 87% for different amplicons. Furthermore, pre-screening of samples for Plasmodium DNA content proved necessary prior to library preparation. Conclusions This study serves as a proof of concept for using leftover clinical material (used RDTs) for large-scale molecular surveillance, encompassing the inherent complications regarding to methodology and analysis when doing so. Factors such as RDT storage prior to DNA extraction and parasitaemia of the infection are likely to have an effect on whether or not parasite DNA can be successfully analysed, and are considered part of the reason the data yield is suboptimal. However, given the necessity of molecular surveillance of anti-malarial resistance in settings where poor infrastructure, poor economy, lack of educated staff and even surges of political instability remain major obstacles to performing clinical studies, obtaining the necessary data from used RDTs, despite suboptimal output, becomes a feasible, affordable and hence a justifiable method. Electronic supplementary material The online version of this article (10.1186/s12936-019-2894-8) contains supplementary material, which is available to authorized users.
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Xu C, Sun H, Wei Q, Li J, Xiao T, Kong X, Wang Y, Zhao G, Wang L, Liu G, Yan G, Huang B, Yin K. Mutation Profile of pfdhfr and pfdhps in Plasmodium falciparum among Returned Chinese Migrant Workers from Africa. Antimicrob Agents Chemother 2019; 63:e01927-18. [PMID: 30803964 DOI: 10.1128/AAC.01927-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 02/17/2019] [Indexed: 01/29/2023] Open
Abstract
We evaluated markers of sulfadoxine-pyrimethamine (SP) resistance in Plasmodium falciparum among 254 returned migrant workers in China from Africa from 2013 to 2016. High prevalences of pfdhfr (97.2%) and pfdhps (96.5%) mutations were observed. The partially resistant genotype was homogeneously distributed in Africa with a modestly high prevalence (48%), whereas the super resistant genotype was only found in West Africa with a very low frequency (1.2%). The findings provided baseline data about the molecular markers of SP resistance.
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Jovel IT, Björkman A, Roper C, Mårtensson A, Ursing J. Unexpected selections of Plasmodium falciparum polymorphisms in previously treatment-naïve areas after monthly presumptive administration of three different anti-malarial drugs in Liberia 1976-78. Malar J 2017; 16:113. [PMID: 28288632 PMCID: PMC5347173 DOI: 10.1186/s12936-017-1747-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 02/21/2017] [Indexed: 01/08/2023] Open
Abstract
Background To assess the effect on malaria prevalence, village specific monthly administrations of pyrimethamine, chlorproguanil, chloroquine or placebo were given to children in four previously treatment-naïve Liberian villages, 1976–78. Plasmodium falciparum in vivo resistance developed to pyrimethamine only. Selection of molecular markers of P. falciparum resistance after 2 years of treatment are reported. Methods Blood samples were collected from 191 study children in a survey in 1978. Polymorphisms in pfcrt, pfmdr1, pfdhfr, pfdhps, pfmrp1 and pfnhe1 genes were determined using PCR-based methods. Results Pfcrt 72–76 CVIET was found in one chloroquine village sample, all remaining samples had pfcrt CVMNK. Pfmdr1 N86 prevalence was 100%. A pfmdr1 T1069ACT→ACG synonymous polymorphism was found in 30% of chloroquine village samples and 3% of other samples (P = 0.008). Variations in pfnhe1 block I were found in all except the chloroquine treated village (P < 0.001). Resistance associated pfdhfr 108N prevalence was 2% in the pyrimethamine village compared to 45–65% elsewhere, including the placebo village (P = 0.001). Conclusions Chloroquine treatment possibly resulted in the development of pfcrt 72–76 CVIET. Selection of pfmdr1 T1069ACG and a pfnhe1 block 1 genotypes indicates that chloroquine treatment exerted a selective pressure on P. falciparum. Pyrimethamine resistance associated pfdhfr 108N was present prior to the introduction of any drug. Decreased pfdhfr 108N frequency concurrent with development of pyrimethamine resistance suggests a non-pfdhfr polymorphisms mediated resistance mechanism. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1747-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Irina T Jovel
- Malaria Research, Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
| | - Anders Björkman
- Malaria Research, Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Cally Roper
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Andreas Mårtensson
- Department of Women's and Children's Health, International Maternal and Child Health Unit, Uppsala University, Uppsala, Sweden
| | - Johan Ursing
- Malaria Research, Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Department of Infectious Diseases, Danderyds Hospital, Stockholm, Sweden
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Kaingona-Daniel EPS, Gomes LR, Gama BE, Almeida-de-Oliveira NK, Fortes F, Ménard D, Daniel-Ribeiro CT, Ferreira-da-Cruz MDF. Low-grade sulfadoxine-pyrimethamine resistance in Plasmodium falciparum parasites from Lubango, Angola. Malar J 2016; 15:309. [PMID: 27267365 PMCID: PMC4895897 DOI: 10.1186/s12936-016-1358-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 05/24/2016] [Indexed: 11/10/2022] Open
Abstract
Background Malaria is a major parasitic disease, affecting millions of people in endemic areas. Plasmodium falciparum parasites are responsible for the most severe cases and its resistance to anti-malarial drugs is notorious. This is a possible obstacle to the effectiveness of intermittent preventive treatment (IPT) based on sulfadoxine–pyrimethamine (SP) cures administrated to pregnant women (IPTp) during their pregnancy. As this intervention is recommended in Angola since 2006, it has assessed, in this country, the molecular profiles in P. falciparumdhfr and dhps, two polymorphic genes associated to pyrimethamine and sulfadoxine resistance, respectively. Methods Blood samples from 52 falciparum patients were collected in Lubango, Angola and pfdhfr and pfdhps polymorphisms were analysed using nested-PCR and DNA sequencing. Results In the pfdhfr gene, the 108N mutation was almost fixed (98 %), followed by 59R (63 %), 51I (46 %), 50R and 164L (2 %, respectively). No 16V/S mutations were found. The most common double mutant genotype was CNRN (59 + 108; 46 %), followed by CICN (51 + 108; 29 %) whereas IRN (51 + 59 + 108; 15 %), CNRNVL (59 + 108 + 164; 2 %) and RICN (50 + 51 + 108; 2 %) triple mutant genotypes were detected. Investigations of the pfdhps gene showed that the 437G mutation was the most prevalent (97 %). Only two and one samples disclosed the 540E (7 %) and the 436A (3 %), respectively. Single mutant SGKAA (437; 86 %) was higher than SGEAA (437 + 540; 7 %) or AGKAA (436 + 437; 3 %) double mutants genotypes. No polymorphism was detected at codons 581G and 613T/S. Combining pfdhfr and pfdhps alleles two triple mutant haplotypes (double mutant in dhfr and single mutant in dhps) were observed: the ACICNVI/SGKAA in 14 (56 %) samples and the ACNRNVI/SGKAA in five (20 %) samples. One quadruple mutant haplotype was detected (ACIRNVI/SGKAA) in six (24 %) P. falciparum samples. No quintuple pfdhfr–pfdhps mutant was noted. Conclusion pfdhfr and pfdhps gene mutations in isolates from Lubango are suggestive of a low-grade SP resistance and IPT for pregnant women and infant based on SP treatment could be effective. Routine molecular studies targeting polymorphism in these two genes need to be routinely conducted at country level.
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Affiliation(s)
- Elsa P S Kaingona-Daniel
- Laboratório de Pesquisa em Malária-Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal) Fiocruz, Rio de Janeiro, Brazil.,Hospital Central Dr. António Agostinho Neto, Lubango, Angola.,Health Progress and Investigation Network of the Portuguese-Speaking Countries Community (RIDESMal/CPLP), Lisbon, Portugal
| | - Larissa Rodrigues Gomes
- Laboratório de Pesquisa em Malária-Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal) Fiocruz, Rio de Janeiro, Brazil.,Health Progress and Investigation Network of the Portuguese-Speaking Countries Community (RIDESMal/CPLP), Lisbon, Portugal
| | - Bianca E Gama
- Laboratório de Pesquisa em Malária-Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Laboratory of Oncovirology, Instituto Nacional de Câncer, Rio de Janeiro, Brazil
| | - Natália K Almeida-de-Oliveira
- Laboratório de Pesquisa em Malária-Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal) Fiocruz, Rio de Janeiro, Brazil.,Health Progress and Investigation Network of the Portuguese-Speaking Countries Community (RIDESMal/CPLP), Lisbon, Portugal
| | - Filomeno Fortes
- Angolan National Malaria Control Programme, National Institute of Public Health, Luanda, Angola.,Health Progress and Investigation Network of the Portuguese-Speaking Countries Community (RIDESMal/CPLP), Lisbon, Portugal
| | - Didier Ménard
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Cláudio Tadeu Daniel-Ribeiro
- Laboratório de Pesquisa em Malária-Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil.,Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal) Fiocruz, Rio de Janeiro, Brazil.,Health Progress and Investigation Network of the Portuguese-Speaking Countries Community (RIDESMal/CPLP), Lisbon, Portugal
| | - Maria de Fátima Ferreira-da-Cruz
- Laboratório de Pesquisa em Malária-Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro, Brazil. .,Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal) Fiocruz, Rio de Janeiro, Brazil. .,Health Progress and Investigation Network of the Portuguese-Speaking Countries Community (RIDESMal/CPLP), Lisbon, Portugal.
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Okombo J, Kamau AW, Marsh K, Sutherland CJ, Ochola-Oyier LI. Temporal trends in prevalence of Plasmodium falciparum drug resistance alleles over two decades of changing antimalarial policy in coastal Kenya. Int J Parasitol Drugs Drug Resist 2014; 4:152-63. [PMID: 25516825 DOI: 10.1016/j.ijpddr.2014.07.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/16/2014] [Accepted: 07/17/2014] [Indexed: 12/17/2022]
Abstract
Genomic changes in malaria parasites over 2 decades of drug pressure were assessed. Chloroquine-sensitive and antifolate-resistant parasite populations rose over time. Steady increases in pfmdr1_N86 and D1246 alleles noted after chloroquine removal. Chloroquine-sensitive parasites 15 years after its removal are highly heterogeneous. Temporal genomic data helps audit the efficacy of withdrawn drugs and those in use.
Molecular surveillance of drug resistance markers through time provides crucial information on genomic adaptations, especially in parasite populations exposed to changing drug pressures. To assess temporal trends of established genotypes associated with tolerance to clinically important antimalarials used in Kenya over the last two decades, we sequenced a region of the pfcrt locus encompassing codons 72–76 of the Plasmodium falciparum chloroquine resistance transporter, full-length pfmdr1 – encoding multi-drug resistance protein, P-glycoprotein homolog (Pgh1) and pfdhfr encoding dihydrofolate reductase, in 485 archived Plasmodium falciparum positive blood samples collected in coastal Kenya at four different time points between 1995 and 2013. Microsatellite loci were also analyzed to compare the genetic backgrounds of parasite populations circulating before and after the withdrawal of chloroquine and sulfadoxine/pyrimethamine. Our results reveal a significant increase in the prevalence of the pfcrt K76 wild-type allele between 1995 and 2013 from 38% to 81.7% (p < 0.0001). In contrast, we noted a significant decline in wild-type pfdhfr S108 allele (p < 0.0001) culminating in complete absence of this allele in 2013. We also observed a significant increase in the prevalence of the wild-type pfmdr1 N86/Y184/D1246 haplotype from 14.6% in 1995 to 66.0% in 2013 (p < 0.0001) and a corresponding decline of the mutant pfmdr1 86Y/184Y/1246Y allele from 36.4% to 0% in 19 years (p < 0.0001). We also show extensive genetic heterogeneity among the chloroquine-sensitive parasites before and after the withdrawal of the drug in contrast to a selective sweep around the triple mutant pfdhfr allele, leading to a mono-allelic population at this locus. These findings highlight the importance of continual surveillance and characterization of parasite genotypes as indicators of the therapeutic efficacy of antimalarials, particularly in the context of changes in malaria treatment policy.
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Geiger C, Compaore G, Coulibaly B, Sie A, Dittmer M, Sanchez C, Lanzer M, Jänisch T. Substantial increase in mutations in the genes pfdhfr and pfdhps puts sulphadoxine-pyrimethamine-based intermittent preventive treatment for malaria at risk in Burkina Faso. Trop Med Int Health 2014; 19:690-697. [PMID: 24674355 DOI: 10.1111/tmi.12305] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Sulphadoxine-pyrimethamine (SP) is widely used as intermittent preventive treatment (IPT) for malaria in pregnant women in Sub-Saharan Africa. There are reports of wide-spread SP resistance in countries where SP had once been used as a first-line treatment. It is unclear whether the development of SP resistance also affects countries where SP is mainly used in the context of IPT, as is the case in Burkina Faso. To assess the efficacy of SP-based IPT, we monitored the prevalence of SP conferring genetic mutations in the genes dhfr and dhps in Plasmodium falciparum populations in a rural area of Burkina Faso over a period of 13 years. METHODS Molecular epidemiological study consisted of six consecutive cross-sectional surveys of rainy and dry seasons (2009-2012). Data from the rainy season in 2000 served as a baseline. Mutations in dhfr and dhps associated with SP resistance were analysed by pyrosequencing in 861 parasite-positive samples. RESULTS The prevalence of the SP resistance conferring triple dhfr mutation 51I, 59R, 108N increased from 1.3% in the rainy season of 2000 to 35.3% in 2009, and 54.3% in 2011 (P ≤ 0.001). Comparing rainy and dry seasons, we observed an increasing step-like pattern with higher prevalence of the dhfr triple mutant in the respective dry season compared with the preceding rainy season. The proportion of the dhps 437Gly mutation in the rainy season of 2000 was 53.2% and subsequently increased to 77.6% in 2009 (P ≤ 0.001). CONCLUSION The increase in molecular markers linked with SP resistance jeopardises the efficacy of IPTp and the planned IPTi interventions in Burkina Faso, calling for careful monitoring of genotypic resistance markers and in vivo validation of IPT efficacy.
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Affiliation(s)
- Carolin Geiger
- Department for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | | | | | - Ali Sie
- Centre de Recherche en Santé à Nouna, Nouna, Burkina Faso
| | - Martin Dittmer
- Department for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Cecilia Sanchez
- Department for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Michael Lanzer
- Department for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Thomas Jänisch
- Department for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
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Moussiliou A, De Tove YSS, Doritchamou J, Luty AJF, Massougbodji A, Alifrangis M, Deloron P, Ndam NT. High rates of parasite recrudescence following intermittent preventive treatment with sulphadoxine-pyrimethamine during pregnancy in Benin. Malar J 2013; 12:195. [PMID: 23758883 PMCID: PMC3686599 DOI: 10.1186/1475-2875-12-195] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 06/04/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Despite widespread parasite resistance to sulphadoxine-pyrimethamine (SP) its use for intermittent preventative treatment during pregnancy remains the policy in Benin and throughout most of sub-Saharan Africa. METHODS In a prospective study, 982 pregnant women were recruited in Benin and followed until delivery. The prevalence of point mutations in the pfdhfr and pfdhps genes associated with Plasmodium falciparum resistance to SP during consecutive antenatal visits was determined. Parasites clearance among women infected at SP intake was assessed by microscopy and PCR. Association between the persistence of parasites and malaria consequences, were investigated. Recurrent parasites were genotyped to identify recrudescences from re-infections. RESULTS The prevalence of pfdhfr/pfdhps quadruple mutants (triple pfdhfr + single pfdhps) was consistently above 80% while quintuple and sextuple mutants remained low. Importantly the higly mutated parasites apparently never included the two key mutations, pfdhfr 164 L or pfdhps 540E. Based on PCR results, SP failed to clear existing parasitaemia in half (48%) of the women who were infected at IPTp schedule. The frequency of recrudescence reached 76% after the second dose. Women with persistent parasitaemia had an increased prevalence of anaemia (P = 0.03). CONCLUSION The data presented here, highlight the inability of SP to ensure optimal antiplasmodial protection in late pregnancy, and invite urgent consideration of an alternative drug or strategy.
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Affiliation(s)
- Azizath Moussiliou
- Institut de Recherche pour le Développement, UMR216 Mère et enfant face aux infections tropicales, Faculté des sciences biologiques et pharmaceutiques, 4, avenue de l’observatoire, Paris 75006, France
- Faculté de Pharmacie, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75270, France
- Centre d’Etude et de Recherche sur le Paludisme associé à la Grossesse et à l’Enfance, Faculté des Science de Santé, Université d’Abomey-Calavi, Cotonou 01 BP 188, Benin
| | - Yolande Sissinto-Savi De Tove
- Centre d’Etude et de Recherche sur le Paludisme associé à la Grossesse et à l’Enfance, Faculté des Science de Santé, Université d’Abomey-Calavi, Cotonou 01 BP 188, Benin
| | - Justin Doritchamou
- Institut de Recherche pour le Développement, UMR216 Mère et enfant face aux infections tropicales, Faculté des sciences biologiques et pharmaceutiques, 4, avenue de l’observatoire, Paris 75006, France
- Faculté de Pharmacie, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75270, France
- Centre d’Etude et de Recherche sur le Paludisme associé à la Grossesse et à l’Enfance, Faculté des Science de Santé, Université d’Abomey-Calavi, Cotonou 01 BP 188, Benin
| | - Adrian JF Luty
- Institut de Recherche pour le Développement, UMR216 Mère et enfant face aux infections tropicales, Faculté des sciences biologiques et pharmaceutiques, 4, avenue de l’observatoire, Paris 75006, France
- Faculté de Pharmacie, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75270, France
| | - Achille Massougbodji
- Centre d’Etude et de Recherche sur le Paludisme associé à la Grossesse et à l’Enfance, Faculté des Science de Santé, Université d’Abomey-Calavi, Cotonou 01 BP 188, Benin
| | - Michael Alifrangis
- Department of International Health, Immunology and Microbiology, Centre for Medical Parasitology Faculty of Health, Medical Sciences, University of Copenhagen, Copenhagen K 1014, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen K 1014, Denmark
| | - Philippe Deloron
- Institut de Recherche pour le Développement, UMR216 Mère et enfant face aux infections tropicales, Faculté des sciences biologiques et pharmaceutiques, 4, avenue de l’observatoire, Paris 75006, France
- Faculté de Pharmacie, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75270, France
| | - Nicaise Tuikue Ndam
- Institut de Recherche pour le Développement, UMR216 Mère et enfant face aux infections tropicales, Faculté des sciences biologiques et pharmaceutiques, 4, avenue de l’observatoire, Paris 75006, France
- Faculté de Pharmacie, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75270, France
- Centre d’Etude et de Recherche sur le Paludisme associé à la Grossesse et à l’Enfance, Faculté des Science de Santé, Université d’Abomey-Calavi, Cotonou 01 BP 188, Benin
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Ako BA, Offianan AT, Johansson M, Penali LK, Nguetta SPA, Sibley CH. Molecular analysis of markers associated with chloroquine and sulfadoxine/pyrimethamine resistance in Plasmodium falciparum malaria parasites from southeastern Côte-d'Ivoire by the time of Artemisinin-based Combination Therapy adoption in 2005. Infect Drug Resist 2012; 5:113-20. [PMID: 22904636 PMCID: PMC3418069 DOI: 10.2147/idr.s31409] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Artemisin-based combination therapies became the recommended therapy in Côte-d'Ivoire in 2005, but both chloroquine (CQ) and sulfadoxine/pyrimethamine (SP) have been heavily used for many decades. Despite this long history, little is known about the geographical distribution of drug resistance-conferring genotypes outside the capital city of Abidjan. In this work, we compared the prevalence of drug-resistant genotypes in Bonoua, an urban area, and Samo, a rural agricultural area, in southeastern Côte-d'Ivoire, about 59 km from Abidjan. PATIENTS AND METHODS Samples were collected from symptomatic patients in both sites during the rainy season in 2005. Genomic DNA was isolated and codons associated with resistance to CQ and SP were analyzed: pfcrt codons Cys-72-Ser, Val-73-Val, Met-74-Ile, Arg-75-Glu, Lys-76-Thr; pfdhfr codons Ala-16-Val, Arg-51-Ile, Cys-59-Arg, Ser-108-Arg/Thr, and Ile-164-Leu; pfdhps codons Ser-436-Ala, Ala-437-Gly, Lys-540-Glu, Ala-581-Gly, and Ala-613-Thr/Ser. RESULTS A limited number of genotypes were found in Bonoua compared with Samo. In both sites, the triple-mutant allele CVIET of pfcrt predominated: 100% in Bonoua and 86.2% in Samo. The wild-type allele, NCSI of pfdhfr, was common - 50% in Bonoua and 38.7% in Samo - but the triple-mutant IRNI and double-mutant NRNI were also frequent (IRNI, 32.6% in Bonoua and 19.4% in Samo; NRNI, 15.2% in Bonoua and 9.7% in Samo). In Samo, a wide range of different genotypes of Pfdhps was observed, with alleles carrying the Gly-437 codon fixed in Bonoua and comprising 73% of the isolates in Samo. CONCLUSION Although these two sites are only 8 km apart, they belonged to very different ecological environments. The overall prevalence of alleles of single-nucleotide polymorphisms associated with resistance to CQ and SP in both locations was among the highest of the region by 2005, although the more rural site showed a more diverse set of alleles and mixed infections. Continued surveillance of these markers will be a useful tool for drug policy, as both CQ and SP are still frequently used years after withdrawal, and SP is recommended by the World Health Organization for intermittent preventive therapy for pregnant women and infants. Data analyzed herein are among the first to be generated during the year of artemisin-based combination-therapy introduction in Côte-d'Ivoire and could be of some interest for malaria policy-makers.
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Affiliation(s)
- Berenger Aristide Ako
- Department of Malariology, Institut Pasteur de Côte-d'Ivoire, Abidjan, Côte d'Ivoire
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