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Duan M, Bai Y, Deng S, Ruan Y, Zeng W, Li X, Wang X, Zhao W, Zhao H, Sun K, Zhu W, Wu Y, Miao J, Kyaw MP, Yang Z, Cui L. Different In Vitro Drug Susceptibility Profile of Plasmodium falciparum Isolates from Two Adjacent Areas of Northeast Myanmar and Molecular Markers for Drug Resistance. Trop Med Infect Dis 2022; 7:tropicalmed7120442. [PMID: 36548697 PMCID: PMC9782301 DOI: 10.3390/tropicalmed7120442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/10/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
The Greater Mekong Subregion (GMS) is the epicenter of antimalarial drug resistance. We determined in vitro susceptibilities to 11 drugs of culture-adapted Plasmodium falciparum isolates from adjacent areas (Laiza and Muse) along the China−Myanmar border. Parasites from this region were highly resistant to chloroquine and pyrimethamine but relatively sensitive to other antimalarial drugs. Consistently, the Dd2-like pfcrt mutations were fixed or almost fixed in both parasite populations, and new mutations mediating piperaquine resistance were not identified. Similarly, several mutations related to pfdhfr and pfdhps were also highly prevalent. Despite their geographical proximity, malaria parasites from Laiza showed significantly higher in vitro resistance to artemisinin derivatives, naphthoquine, pyronaridine, lumefantrine, and pyrimethamine than parasites from Muse. Likewise, the pfdhfr N51I, pfdhps A581G, pfmrp1 H785N, and pfk13 F446I mutations were significantly more frequent in Laiza than in Muse (p < 0.05). For the pfmdr1 mutations, Y184F was found only in Laiza (70%), whereas F1226Y was identified only in Muse (31.8%). Parasite isolates from Laiza showed a median RSA value of 5.0%, significantly higher than the 2.4% in Muse. Altogether, P. falciparum parasite populations from neighboring regions in the GMS may diverge substantially in their resistance to several antimalarial drugs. This information about different parasite populations will guide antimalarial treatment policies to effectively manage drug resistance during malaria elimination.
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Affiliation(s)
- Mengxi Duan
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming 650500, China
| | - Yao Bai
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming 650500, China
| | - Shuang Deng
- Department of Pathology, Kunming Medical University, Kunming 650500, China
| | - Yonghua Ruan
- Department of Pathology, Kunming Medical University, Kunming 650500, China
| | - Weilin Zeng
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming 650500, China
| | - Xiaosong Li
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming 650500, China
| | - Xun Wang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming 650500, China
| | - Wei Zhao
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming 650500, China
| | - Hui Zhao
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming 650500, China
| | - Kemin Sun
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming 650500, China
| | - Wenya Zhu
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming 650500, China
| | - Yiman Wu
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming 650500, China
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL 33612, USA
| | | | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming 650500, China
- Correspondence: (Z.Y.); (L.C.); Tel.: +86-871-68225541 (Z.Y.); +1-(813)-974-9606 (L.C.)
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL 33612, USA
- Correspondence: (Z.Y.); (L.C.); Tel.: +86-871-68225541 (Z.Y.); +1-(813)-974-9606 (L.C.)
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Lê HG, Naw H, Kang JM, Võ TC, Myint MK, Htun ZT, Lee J, Yoo WG, Kim TS, Shin HJ, Na BK. Molecular Profiles of Multiple Antimalarial Drug Resistance Markers in Plasmodium falciparum and Plasmodium vivax in the Mandalay Region, Myanmar. Microorganisms 2022; 10:2021. [PMID: 36296297 PMCID: PMC9612053 DOI: 10.3390/microorganisms10102021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/05/2022] [Accepted: 10/08/2022] [Indexed: 09/21/2023] Open
Abstract
Emergence and spreading of antimalarial drug resistant malaria parasites are great hurdles to combating malaria. Although approaches to investigate antimalarial drug resistance status in Myanmar malaria parasites have been made, more expanded studies are necessary to understand the nationwide aspect of antimalarial drug resistance. In the present study, molecular epidemiological analysis for antimalarial drug resistance genes in Plasmodium falciparum and P. vivax from the Mandalay region of Myanmar was performed. Blood samples were collected from patients infected with P. falciparum and P. vivax in four townships around the Mandalay region, Myanmar in 2015. Partial regions flanking major mutations in 11 antimalarial drug resistance genes, including seven genes (pfdhfr, pfdhps, pfmdr-1, pfcrt, pfk13, pfubp-1, and pfcytb) of P. falciparum and four genes (pvdhfr, pvdhps, pvmdr-1, and pvk12) of P. vivax were amplified, sequenced, and overall mutation patterns in these genes were analyzed. Substantial levels of mutations conferring antimalarial drug resistance were detected in both P. falciparum and P. vivax isolated in Mandalay region of Myanmar. Mutations associated with sulfadoxine-pyrimethamine resistance were found in pfdhfr, pfdhps, pvdhfr, and pvdhps of Myanmar P. falciparum and P. vivax with very high frequencies up to 90%. High or moderate levels of mutations were detected in genes such as pfmdr-1, pfcrt, and pvmdr-1 associated with chloroquine resistance. Meanwhile, low frequency mutations or none were found in pfk13, pfubp-1, pfcytb, and pvk12 of the parasites. Overall molecular profiles for antimalarial drug resistance genes in malaria parasites in the Mandalay region suggest that parasite populations in the region have substantial levels of mutations conferring antimalarial drug resistance. Continuous monitoring of mutations linked with antimalarial drug resistance is necessary to provide useful information for policymakers to plan for proper antimalarial drug regimens to control and eliminate malaria in the country.
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Affiliation(s)
- Hương Giang Lê
- Department of Parasitology and Tropical Medicine, Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Korea
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea
| | - Haung Naw
- Department of Parasitology and Tropical Medicine, Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Korea
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea
| | - Jung-Mi Kang
- Department of Parasitology and Tropical Medicine, Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Korea
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea
| | - Tuấn Cường Võ
- Department of Parasitology and Tropical Medicine, Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Korea
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea
| | - Moe Kyaw Myint
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin 05062, Myanmar
| | - Zaw Than Htun
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin 05062, Myanmar
| | - Jinyoung Lee
- Department of Tropical Medicine, Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon 22212, Korea
| | - Won Gi Yoo
- Department of Parasitology and Tropical Medicine, Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Korea
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea
| | - Tong-Soo Kim
- Department of Tropical Medicine, Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon 22212, Korea
| | - Ho-Joon Shin
- Department of Microbiology, Ajou University College of Medicine, Suwon 16499, Korea
| | - Byoung-Kuk Na
- Department of Parasitology and Tropical Medicine, Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Korea
- Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea
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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] [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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Zhao Y, Liu Z, Soe MT, Wang L, Soe TN, Wei H, Than A, Aung PL, Li Y, Zhang X, Hu Y, Wei H, Zhang Y, Burgess J, Siddiqui FA, Menezes L, Wang Q, Kyaw MP, Cao Y, Cui L. Genetic Variations Associated with Drug Resistance Markers in Asymptomatic Plasmodium falciparum Infections in Myanmar. Genes (Basel) 2019; 10:genes10090692. [PMID: 31505774 PMCID: PMC6770986 DOI: 10.3390/genes10090692] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/31/2019] [Accepted: 09/04/2019] [Indexed: 12/30/2022] Open
Abstract
The emergence and spread of drug resistance is a problem hindering malaria elimination in Southeast Asia. In this study, genetic variations in drug resistance markers of Plasmodium falciparum were determined in parasites from asymptomatic populations located in three geographically dispersed townships of Myanmar by PCR and sequencing. Mutations in dihydrofolate reductase (pfdhfr), dihydropteroate synthase (pfdhps), chloroquine resistance transporter (pfcrt), multidrug resistance protein 1 (pfmdr1), multidrug resistance-associated protein 1 (pfmrp1), and Kelch protein 13 (k13) were present in 92.3%, 97.6%, 84.0%, 98.8%, and 68.3% of the parasites, respectively. The pfcrt K76T, pfmdr1 N86Y, pfmdr1 I185K, and pfmrp1 I876V mutations were present in 82.7%, 2.5%, 87.5%, and 59.8% isolates, respectively. The most prevalent haplotypes for pfdhfr, pfdhps, pfcrt and pfmdr1 were 51I/59R/108N/164L, 436A/437G/540E/581A, 74I/75E/76T/220S/271E/326N/356T/371I, and 86N/130E/184Y/185K/1225V, respectively. In addition, 57 isolates had three different point mutations (K191T, F446I, and P574L) and three types of N-terminal insertions (N, NN, NNN) in the k13 gene. In total, 43 distinct haplotypes potentially associated with multidrug resistance were identified. These findings demonstrate a high prevalence of multidrug-resistant P. falciparum in asymptomatic infections from diverse townships in Myanmar, emphasizing the importance of targeting asymptomatic infections to prevent the spread of drug-resistant P.falciparum.
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Affiliation(s)
- Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Ziling Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Myat Thu Soe
- Myanmar Health Network Organization, Yangon 11211, Myanmar.
| | - Lin Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Than Naing Soe
- Department of Public Health, Ministry of Health and Sports, Nay Pyi Taw 15011, Myanmar.
| | - Huanping Wei
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Aye Than
- Myanmar Health Network Organization, Yangon 11211, Myanmar.
| | - Pyae Linn Aung
- Myanmar Health Network Organization, Yangon 11211, Myanmar.
| | - Yuling Li
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Xuexing Zhang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Yubing Hu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Haichao Wei
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Yangminghui Zhang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Jessica Burgess
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA.
| | - Faiza A Siddiqui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA.
| | - Lynette Menezes
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA.
| | - Qinghui Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | | | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang 110122, China.
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA.
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Dokunmu TM, Adjekukor CU, Yakubu OF, Bello AO, Adekoya JO, Akinola O, Amoo EO, Adebayo AH. Asymptomatic malaria infections and Pfmdr1 mutations in an endemic area of Nigeria. Malar J 2019; 18:218. [PMID: 31248414 PMCID: PMC6598231 DOI: 10.1186/s12936-019-2833-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 06/09/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Malaria eradication globally is yet to be achieved and transmission is sustained in many endemic countries. Plasmodium falciparum continues to develop resistance to currently available anti-malarial drugs, posing great problems for malaria elimination. This study evaluates the frequencies of asymptomatic infection and multidrug resistance-1 (mdr-1) gene mutations in parasite isolates, which form the basis for understanding persistently high incidence in South West, Nigeria. METHODS A total of 535 individuals aged from 6 months were screened during the epidemiological survey evaluating asymptomatic transmission. Parasite prevalence was determined by histidine-rich protein II rapid detection kit (RDT) in healthy individuals. Plasmodium falciparum mdr-1 gene mutations were detected by polymerase chain reaction (PCR) followed by restriction enzyme digest and electrophoresis to determine polymorphism in parasite isolates. Sequencing was done to confirm polymorphism. Proportions were compared using Chi-square test at p value < 0.05. RESULTS Malaria parasites were detected by RDT in 204 (38.1%) individuals. Asymptomatic infection was detected in 117 (57.3%) and symptomatic malaria confirmed in 87 individuals (42.6%). Overall, individuals with detectable malaria by RDT was significantly higher in individuals with symptoms, 87 of 197 (44.2%), than asymptomatic persons; 117 of 338 (34.6%), p = 0.02. In a sub-set of 75 isolates, 18(24%) and 14 (18.6%) individuals had Pfmdr1 86Y and 1246Y mutations. CONCLUSIONS There is still high malaria transmission rate in Nigeria with higher incidence of asymptomatic infections. These parasites harbour mutations on Pfmdr1 which contribute to artemisinin partner drug resistance; surveillance strategies to reduce the spread of drug resistance in endemic areas are needed to eliminate the reservoir of malaria parasites that can mitigate the eradication of malaria in Nigeria.
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Affiliation(s)
| | | | - Omolara F Yakubu
- Department of Biochemistry, Covenant University, Ota, 23401, Nigeria
| | - Adetutu O Bello
- Department of Biological Sciences, Covenant University, Ota, 23401, Nigeria
| | - Jarat O Adekoya
- Department of Biological Sciences, Covenant University, Ota, 23401, Nigeria
| | - Olugbenga Akinola
- Department of Pharmacology and Therapeutics, University of Ilorin, Ilorin, 24003, Nigeria
| | - Emmanuel O Amoo
- Demography and Social Statistics Unit, Department of Economics and Development Studies, Covenant University, Ota, 23401, Nigeria
| | - Abiodun H Adebayo
- Department of Biochemistry, Covenant University, Ota, 23401, Nigeria.
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Bai Y, Zhang J, Geng J, Xu S, Deng S, Zeng W, Wang Z, Ngassa Mbenda HG, Zhang J, Li N, Wu Y, Li C, Liu H, Ruan Y, Cao Y, Yang Z, Cui L. Longitudinal surveillance of drug resistance in Plasmodium falciparum isolates from the China-Myanmar border reveals persistent circulation of multidrug resistant parasites. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2018; 8:320-328. [PMID: 29793059 PMCID: PMC6039318 DOI: 10.1016/j.ijpddr.2018.05.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 05/04/2018] [Accepted: 05/13/2018] [Indexed: 11/24/2022]
Abstract
Multidrug-resistant Plasmodium falciparum in the Greater Mekong Subregion of Southeast Asia is a major threat to malaria elimination and requires close surveillance. In this study, we collected 107 longitudinal clinical samples of P. falciparum in 2007–2012 from the malaria hypoendemic region of the China-Myanmar border and measured their in vitro susceptibilities to 10 antimalarial drugs. Overall, parasites had significantly different IC50 values to all the drugs tested as compared to the reference 3D7 strain. Parasites were also genotyped in seven genes that were associated with drug resistance including pfcrt, pfmdr1, pfmrp1, pfdhfr, pfdhps, pfnhe1, and PfK13 genes. Despite withdrawal of chloroquine and antifolates from treating P. falciparum, parasites remained highly resistant to these drugs and mutations in pfcrt, pfdhfr, and pfdhps genes were highly prevalent and almost reached fixation in the study parasite population. Except for pyronaridine, quinine and lumefantrine, all other tested drugs exhibited significant temporal variations at least between some years, but only chloroquine and piperaquine had a clear temporal trend of continuous increase of IC50s. For the pfmrp1 gene, several mutations were associated with altered sensitivity to a number of drugs tested including chloroquine, piperaquine, lumefantrine and dihydroartemisinin. The association of PfK13 mutations with resistance to multiple drugs suggests potential evolution of PfK13 mutations amid multidrug resistance genetic background. Furthermore, network analysis of drug resistance genes indicated that certain haplotypes associated multidrug resistance persisted in these years, albeit there were year-to-year fluctuations of the predominant haplotypes. P. falciparum from China-Myanmar border was followed for in vitro drug sensitivity. Parasites displayed in vitro resistance to several antimalarial drugs. Resistance to chloroquine and piperaquine escalated by years. Genotyping genes associated with drug resistance confirmed in vitro assay results.
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Affiliation(s)
- Yao Bai
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China; Department of Pharmacology, Kunming Medical University, Kunming, China
| | - Jiaqi Zhang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Jinting Geng
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Shiling Xu
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Shuang Deng
- Department of Pathology, Kunming Medical University, Kunming, China
| | - Weilin Zeng
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Zenglei Wang
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA
| | | | - Jie Zhang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Na Li
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China; Department of Pharmacology, Kunming Medical University, Kunming, China
| | - Yanrui Wu
- Department of Cell Biology and Medical Genetics, Kunming Medical University, Kunming, Yunnan Province 650500, China
| | - Cuiying Li
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Huae Liu
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Yonghua Ruan
- Department of Pathology, Kunming Medical University, Kunming, China
| | - Yaming Cao
- Department of Immunology, China Medical University, Shenyang, Liaoning 110122 China
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China.
| | - Liwang Cui
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China; Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA.
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7
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Significant Divergence in Sensitivity to Antimalarial Drugs between Neighboring Plasmodium falciparum Populations along the Eastern Border of Myanmar. Antimicrob Agents Chemother 2017; 61:AAC.01689-16. [PMID: 27919892 DOI: 10.1128/aac.01689-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 11/18/2016] [Indexed: 12/29/2022] Open
Abstract
Malaria parasites in different areas where malaria is endemic display different levels of resistance to antimalarial drugs as the result of varied drug use histories. To provide updated knowledge of drug sensitivities during the malaria elimination phase in Southeast Asia, an epicenter of multidrug resistance, we determined in vitro susceptibilities of culture-adapted Plasmodium falciparum isolates from two eastern border regions (Wa and Kachin) of Myanmar to 10 drugs. Despite their close proximity, the Kachin parasites displayed higher 50% inhibitory concentrations than the Wa parasites to chloroquine, piperaquine, naphthoquine, mefloquine, quinine, pyrimethamine, pyronaridine, lumefantrine, and dihydroartemisinin. Genotyping of genes associated with drug resistance also showed significant differences in the prevalence rates of mutant alleles between the two regions. Particularly, major pfdhfr mutations mediating pyrimethamine resistance and the pfdhps A437G mutation had significantly higher frequencies in the Kachin parasites (P < 0.005). Moreover, when pfdhfr and pfdhps were considered together, the wild-type allele was found only in the Wa samples (22.6%). In addition, the pfmdr1 Y184F mutation reached 38.7% in the Kachin parasites, compared to 9.7% in the Wa parasites, whereas N86Y was only detected in the Wa parasites, at 22.6%. Furthermore, the F446I mutation and all mutations in the propeller domain of the PfK13 gene were significantly more frequent in the Kachin parasites. Collectively, this work demonstrates that even in spatially closely separated regions, parasites can exhibit drastic differences in drug sensitivities and genetic makeups underlying drug resistance, which may reflect regionally different drug histories and genetic drift of these isolated parasite populations.
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Ramani S, Parija SC, Mandal J, Hamide A, Bhat V. Detection of chloroquine and artemisinin resistance molecular markers in Plasmodium falciparum: A hospital based study. Trop Parasitol 2016; 6:69-77. [PMID: 26998436 PMCID: PMC4778185 DOI: 10.4103/2229-5070.175110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Introduction: Emergence of chloroquine (CQ) resistance in Plasmodium falciparum has increased the morbidity and mortality of falciparum malaria worldwide. Artemisinin-based combination therapies are now recommended by the World Health Organization as the first line treatment for falciparum malaria. Numerous molecular markers have been implicated in the CQ and artemisinin resistance. Materials and Methods: A total of 26 confirmed cases of falciparum malaria (by giemsa stained thick and thin smear, quantitative buffy coat, immunochromatographic test, or polymerase chain reaction [PCR]) were included in the study. About 5 ml of ethylenediaminetetraacetic acid blood sample was collected and stored at −20°C till use. Plasmodium DNA was extracted using QIAamp whole blood DNA extraction kit. PCR was done to amplify pfcrt, pfmdr1, pfserca, and pfmrp1 genes and the amplicons obtained were sequenced by Macrogen, Inc., Korea. Single nucleotide polymorphism (SNP) analysis was done using Bio-Edit Sequence Alignment Editor. Results: Out of the four genes targeted, we noted a SNP in the pfcrt gene alone. This SNP (G > T) was noted in the 658th position of the gene, which was seen in 13 patients. The pfmdr1 and pfserca genes were present in 9 and 14 patients respectively. But we could not find any SNPs in these genes. This SNP in pfcrt gene was not significantly associated with any adverse outcome and neither altered disease progression. Conclusion: Presence of a single SNP may not be associated with any adverse clinical outcome. As the sample size was small, we may have not been able to detect any other known or unknown polymorphisms.
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Affiliation(s)
- S Ramani
- Department of Microbiology, Jawaharlal Nehru Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Subhash Chandra Parija
- Department of Microbiology, Jawaharlal Nehru Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Jharna Mandal
- Department of Microbiology, Jawaharlal Nehru Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Abdoul Hamide
- Department of Medicine, Jawaharlal Nehru Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Vishnu Bhat
- Department of Paediatrics, Jawaharlal Nehru Institute of Postgraduate Medical Education and Research, Puducherry, India
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Artemisinin resistance at the China-Myanmar border and association with mutations in the K13 propeller gene. Antimicrob Agents Chemother 2015; 59:6952-9. [PMID: 26324266 DOI: 10.1128/aac.01255-15] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/18/2015] [Indexed: 02/07/2023] Open
Abstract
Artemisinin resistance in Plasmodium falciparum parasites in Southeast Asia is a major concern for malaria control. Its emergence at the China-Myanmar border, where there have been more than 3 decades of artemisinin use, has yet to be investigated. Here, we comprehensively evaluated the potential emergence of artemisinin resistance and antimalarial drug resistance status in P. falciparum using data and parasites from three previous efficacy studies in this region. These efficacy studies of dihydroartemisinin-piperaquine combination and artesunate monotherapy of uncomplicated falciparum malaria in 248 P. falciparum patients showed an overall 28-day adequate clinical and parasitological response of >95% and day 3 parasite-positive rates of 6.3 to 23.1%. Comparison of the 57 K13 sequences (24 and 33 from day 3 parasite-positive and -negative cases, respectively) identified nine point mutations in 38 (66.7%) samples, of which F446I (49.1%) and an N-terminal NN insertion (86.0%) were predominant. K13 propeller mutations collectively, the F446I mutation alone, and the NN insertion all were significantly associated with day 3 parasite positivity. Increased ring-stage survival determined using the ring-stage survival assay (RSA) was highly associated with the K13 mutant genotype. Day 3 parasite-positive isolates had ∼10 times higher ring survival rates than day 3 parasite-negative isolates. Divergent K13 mutations suggested independent evolution of artemisinin resistance. Taken together, this study confirmed multidrug resistance and emergence of artemisinin resistance in P. falciparum at the China-Myanmar border. RSA and K13 mutations are useful phenotypic and molecular markers for monitoring artemisinin resistance.
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10
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Cui L, Mharakurwa S, Ndiaye D, Rathod PK, Rosenthal PJ. Antimalarial Drug Resistance: Literature Review and Activities and Findings of the ICEMR Network. Am J Trop Med Hyg 2015; 93:57-68. [PMID: 26259943 PMCID: PMC4574275 DOI: 10.4269/ajtmh.15-0007] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 04/27/2015] [Indexed: 11/07/2022] Open
Abstract
Antimalarial drugs are key tools for the control and elimination of malaria. Recent decreases in the global malaria burden are likely due, in part, to the deployment of artemisinin-based combination therapies. Therefore, the emergence and potential spread of artemisinin-resistant parasites in southeast Asia and changes in sensitivities to artemisinin partner drugs have raised concerns. In recognition of this urgent threat, the International Centers of Excellence for Malaria Research (ICEMRs) are closely monitoring antimalarial drug efficacy and studying the mechanisms underlying drug resistance. At multiple sentinel sites of the global ICEMR network, research activities include clinical studies to track the efficacies of antimalarial drugs, ex vivo/in vitro assays to measure drug susceptibilities of parasite isolates, and characterization of resistance-mediating parasite polymorphisms. Taken together, these efforts offer an increasingly comprehensive assessment of the efficacies of antimalarial therapies, and enable us to predict the emergence of drug resistance and to guide local antimalarial drug policies. Here we briefly review worldwide antimalarial drug resistance concerns, summarize research activities of the ICEMRs related to drug resistance, and assess the global impacts of the ICEMR programs.
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Affiliation(s)
- Liwang Cui
- *Address correspondence to Liwang Cui, Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA 16802, E-mail: or Philip J. Rosenthal, Department of Medicine, Box 0811, University of California, San Francisco, CA 94110. E-mail:
| | | | | | | | - Philip J. Rosenthal
- *Address correspondence to Liwang Cui, Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA 16802, E-mail: or Philip J. Rosenthal, Department of Medicine, Box 0811, University of California, San Francisco, CA 94110. E-mail:
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11
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Multidrug resistance: an emerging crisis. Interdiscip Perspect Infect Dis 2014; 2014:541340. [PMID: 25140175 PMCID: PMC4124702 DOI: 10.1155/2014/541340] [Citation(s) in RCA: 279] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 07/03/2014] [Indexed: 01/15/2023] Open
Abstract
The resistance among various microbial species (infectious agents) to different antimicrobial drugs has emerged as a cause of public health threat all over the world at a terrifying rate. Due to the pacing advent of new resistance mechanisms and decrease in efficiency of treating common infectious diseases, it results in failure of microbial response to standard treatment, leading to prolonged illness, higher expenditures for health care, and an immense risk of death. Almost all the capable infecting agents (e.g., bacteria, fungi, virus, and parasite) have employed high levels of multidrug resistance (MDR) with enhanced morbidity and mortality; thus, they are referred to as “super bugs.” Although the development of MDR is a natural phenomenon, the inappropriate use of antimicrobial drugs, inadequate sanitary conditions, inappropriate food-handling, and poor infection prevention and control practices contribute to emergence of and encourage the further spread of MDR. Considering the significance of MDR, this paper, emphasizes the problems associated with MDR and the need to understand its significance and mechanisms to combat microbial infections.
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12
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Chen K, Sun L, Lin Y, Fan Q, Zhao Z, Hao M, Feng G, Wu Y, Cui L, Yang Z. Competition between Plasmodium falciparum strains in clinical infections during in vitro culture adaptation. INFECTION GENETICS AND EVOLUTION 2014; 24:105-10. [PMID: 24667050 DOI: 10.1016/j.meegid.2014.03.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 03/09/2014] [Accepted: 03/13/2014] [Indexed: 12/20/2022]
Abstract
We evaluated the dynamics of parasite populations during in vitro culture adaptation in 15 mixed Plasmodium falciparum infections, which were collected from a hypoendemic area near the China-Myanmar border. Allele types at the msp1 block 2 in the initial clinical samples and during subsequent culture were quantified weekly using a quantitative PCR method. All mixed infections carried two allele types based on the msp1 genotyping result. We also genotyped several polymorphic sites in the dhfr, dhps and mdr1 genes on day 0 and day 28, which showed that most of the common sites analyzed were monomorphic. Two of the three clinical samples mixed at dhps 581 remained stable while one changed to wild-type during the culture. During in vitro culture, we observed a gradual loss of parasite populations with 10 of the 15 mixed infections becoming monoclonal by day 28 based on the msp1 allele type. In most cases, the more abundant msp1 allele types in the clinical blood samples at the beginning of culture became the sole or predominant allele types on day 28. These results suggest that some parasites may have growth advantages and the loss of parasite populations during culture adaptation of mixed infections may lead to biased results when comparing the phenotypes such as drug sensitivity of the culture-adapted parasites.
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Affiliation(s)
- Kexuan Chen
- Department of Pathogen Biology and Immunology, Kunming Medical University, Yunnan Province 650500, China
| | - Ling Sun
- Department of Pathogen Biology and Immunology, Kunming Medical University, Yunnan Province 650500, China
| | - Yingxue Lin
- Center for Disease Control and Prevention, Yingjiang, Yunnan Province 679300, China
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning Province, China
| | - Zhenjun Zhao
- Dalian Institute of Biotechnology, Dalian, Liaoning Province, China
| | - Mingming Hao
- Department of Pathogen Biology and Immunology, Kunming Medical University, Yunnan Province 650500, China
| | - Guohua Feng
- Center for Biomedical Engineering Research, Kunming Medical University, Yunnan Province 650500, China
| | - Yanrui Wu
- Department of Cell Biology and Genetics, Kunming Medical University, Yunnan Province 650500, China
| | - Liwang Cui
- Department of Entomology, The Pennsylvania State University, 501 ASI Bldg., University Park, PA 16802, USA.
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Yunnan Province 650500, China.
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Pakalapati D, Garg S, Middha S, Acharya J, Subudhi AK, Boopathi AP, Saxena V, Kochar SK, Kochar DK, Das A. Development and evaluation of a 28S rRNA gene-based nested PCR assay for P. falciparum and P. vivax. Pathog Glob Health 2014; 107:180-8. [PMID: 23816509 DOI: 10.1179/2047773213y.0000000090] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The 28S rRNA gene was amplified and sequenced from P. falciparum and P. vivax isolates collected from northwest India. Based upon the sequence diversity of the Plasmodium 28SrRNA gene in comparison with its human counterpart, various nested polymerase chain reaction (PCR) primers were designed from the 3R region of the 28SrRNA gene and evaluated on field isolates. This is the first report demonstrating the utility of this gene for species-specific diagnosis of malaria for these two species, prevalent in India. The initial evaluation on 363 clinical isolates indicated that, in comparison with microscopy, which showed sensitivity and specificity of 85·39% and 100% respectively, the sensitivity and specificity of the nested PCR assay was found to be 99·08% and 100% respectively. This assay was also successful in detecting mixed infections that are undetected by microscopy. Our results demonstrate the utility of the 28S rRNA gene as a diagnostic target for the detection of the major plasmodial species infecting humans.
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Affiliation(s)
- Deepak Pakalapati
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, Rajasthan, India
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14
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Haque U, Glass GE, Haque W, Islam N, Roy S, Karim J, Noedl H. Antimalarial drug resistance in Bangladesh, 1996–2012. Trans R Soc Trop Med Hyg 2013; 107:745-52. [DOI: 10.1093/trstmh/trt088] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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15
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Jamal S, Periwal V, Scaria V. Predictive modeling of anti-malarial molecules inhibiting apicoplast formation. BMC Bioinformatics 2013; 14:55. [PMID: 23419172 PMCID: PMC3599641 DOI: 10.1186/1471-2105-14-55] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 02/04/2013] [Indexed: 11/13/2022] Open
Abstract
Background Malaria is a major healthcare problem worldwide resulting in an estimated 0.65 million deaths every year. It is caused by the members of the parasite genus Plasmodium. The current therapeutic options for malaria are limited to a few classes of molecules, and are fast shrinking due to the emergence of widespread resistance to drugs in the pathogen. The recent availability of high-throughput phenotypic screen datasets for antimalarial activity offers a possibility to create computational models for bioactivity based on chemical descriptors of molecules with potential to accelerate drug discovery for malaria. Results In the present study, we have used high-throughput screen datasets for the discovery of apicoplast inhibitors of the malarial pathogen as assayed from the delayed death response. We employed machine learning approach and developed computational predictive models to predict the biological activity of new antimalarial compounds. The molecules were further evaluated for common substructures using a Maximum Common Substructure (MCS) based approach. Conclusions We created computational models using state-of-the-art machine learning algorithms. The models were evaluated based on multiple statistical criteria. We found Random Forest based approach provides for better accuracy as assessed from ROC curve analysis. We further evaluated the active molecules using a substructure based approach to identify common substructures enriched in the active set. We argue that the computational models generated could be effectively used to screen large molecular datasets to prioritize them for phenotypic screens, drastically reducing cost while improving the hit rate.
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Affiliation(s)
- Salma Jamal
- CSIR Open Source Drug Discovery Unit, Anusandhan Bhavan, Delhi 110001, India
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16
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Yuan L, Zhao H, Wu L, Li X, Parker D, Xu S, Zhao Y, Feng G, Wang Y, Yan G, Fan Q, Yang Z, Cui L. Plasmodium falciparum populations from northeastern Myanmar display high levels of genetic diversity at multiple antigenic loci. Acta Trop 2013; 125:53-9. [PMID: 23000544 DOI: 10.1016/j.actatropica.2012.09.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 09/07/2012] [Accepted: 09/12/2012] [Indexed: 11/27/2022]
Abstract
Levels of genetic diversity of the malaria parasites and multiclonal infections are correlated with transmission intensity. In order to monitor the effect of strengthened malaria control efforts in recent years at the China-Myanmar border area, we followed the temporal dynamics of genetic diversity of three polymorphic antigenic markers msp1, msp2, and glurp in the Plasmodium falciparum populations. Despite reduced malaria prevalence in the region, parasite populations exhibited high levels of genetic diversity. Genotyping 258 clinical samples collected in four years detected a total of 22 PCR size alleles. Multiclonal infections were detected in 45.7% of the patient samples, giving a minimum multiplicity of infection of 1.41. The majority of alleles experienced significant temporal fluctuations through the years. Haplotype diversity based on the three-locus genotypes ranged from the lowest in 2009 at 0.33 to the highest in 2010 at 0.80. Sequencing of msp1 fragments from 36 random samples of five allele size groups detected 13 different sequences, revealing an additional layer of genetic complexity. This study suggests that despite reduced prevalence of malaria infections in this region, the parasite population size and transmission intensity remained high enough to allow effective genetic recombination of the parasites and continued maintenance of genetic diversity.
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Affiliation(s)
- Lili Yuan
- Department of Parasitology, Kunming Medical University, Kunming, Yunnan Province, China
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17
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Brown T, Smith LS, Oo EKS, Shawng K, Lee TJ, Sullivan D, Beyrer C, Richards AK. Molecular surveillance for drug-resistant Plasmodium falciparum in clinical and subclinical populations from three border regions of Burma/Myanmar: cross-sectional data and a systematic review of resistance studies. Malar J 2012; 11:333. [PMID: 22992214 PMCID: PMC3518194 DOI: 10.1186/1475-2875-11-333] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 08/15/2012] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Confirmation of artemisinin-delayed parasite clearance in Plasmodium falciparum along the Thai-Myanmar border has inspired a global response to contain and monitor drug resistance to avert the disastrous consequences of a potential spread to Africa. However, resistance data from Myanmar are sparse, particularly from high-risk areas where limited health services and decades of displacement create conditions for resistance to spread. Subclinical infections may represent an important reservoir for resistance genes that confer a fitness disadvantage relative to wild-type alleles. This study estimates the prevalence of resistance genotypes in three previously unstudied remote populations in Myanmar and tests the a priori hypothesis that resistance gene prevalence would be higher among isolates collected from subclinical infections than isolates collected from febrile clinical patients. A systematic review of resistance studies is provided for context. METHODS Community health workers in Karen and Kachin States and an area spanning the Indo-Myanmar border collected dried blood spots from 988 febrile clinical patients and 4,591 villagers with subclinical infection participating in routine prevalence surveys. Samples positive for P. falciparum 18 s ribosomal RNA by real-time PCR were genotyped for P. falciparum multidrug resistance protein (pfmdr1) copy number and the pfcrt K76T polymorphism using multiplex real-time PCR. RESULTS Pfmdr1 copy number increase and the pfcrt K76 polymorphism were determined for 173 and 269 isolates, respectively. Mean pfmdr1 copy number was 1.2 (range: 0.7 to 3.7). Pfmdr1 copy number increase was present in 17.5%, 9.6% and 11.1% of isolates from Karen and Kachin States and the Indo-Myanmar border, respectively. Pfmdr1 amplification was more prevalent in subclinical isolates (20.3%) than clinical isolates (6.4%, odds ratio 3.7, 95% confidence interval 1.1 - 12.5). Pfcrt K76T prevalence ranged from 90-100%. CONCLUSIONS Community health workers can contribute to molecular surveillance of drug resistance in remote areas of Myanmar. Marginal and displaced populations under-represented among previous resistance investigations can and should be included in resistance surveillance efforts, particularly once genetic markers of artemisinin-delayed parasite clearance are identified. Subclinical infections may contribute to the epidemiology of drug resistance, but determination of gene amplification from desiccated filter samples requires further validation when DNA concentration is low.
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Affiliation(s)
- Tyler Brown
- Johns Hopkins University School of Medicine, Broadway Research Building, 733 N. Broadway, Suite 147, Baltimore, MD, 21205, USA
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
| | - Linda S Smith
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
| | - Eh Kalu Shwe Oo
- Karen Department of Health and Welfare, PO Box 189, Mae Sot, Tak, 63110, Thailand
| | - Kum Shawng
- Office of the Director of the Health Department, Kachin Baptist Convention 135/Shan Su (South), Myitkyina, Kachin State, Myanmar
| | - Thomas J Lee
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
- School of Medicine, University of California at Los Angeles, 924 Westwood Blvd, Suite 300, Los Angeles, CA, 90024, USA
| | - David Sullivan
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health 615 North Wolfe St, Room E5628, Baltimore, MD, 21205, USA
| | - Chris Beyrer
- Department of Epidemiology Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St., Suite E7152, Baltimore, MD, 21205, USA
| | - Adam K Richards
- Global Health Access Program, 2550 Ninth Street, Ste 111, Berkeley, CA, 94710, USA
- Department of General Internal Medicine and Health Services Research, University of California at Los Angeles, 911 Broxton Ave, Los Angeles, CA, 90025, USA
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Wang Z, Parker D, Meng H, Wu L, Li J, Zhao Z, Zhang R, Fan Q, Wang H, Cui L, Yang Z. In vitro sensitivity of Plasmodium falciparum from China-Myanmar border area to major ACT drugs and polymorphisms in potential target genes. PLoS One 2012; 7:e30927. [PMID: 22701513 PMCID: PMC3365119 DOI: 10.1371/journal.pone.0030927] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 12/25/2011] [Indexed: 01/16/2023] Open
Abstract
Drug resistance has always been one of the most important impediments to global malaria control. Artemisinin resistance has recently been confirmed in the Greater Mekong Subregion (GMS) and efforts for surveillance and containment are intensified. To determine potential mechanisms of artemisinin resistance and monitor the emergence and spread of resistance in other regions of the GMS, we investigated the in vitro sensitivity of 51 culture-adapted parasite isolates from the China-Myanmar border area to four drugs. The 50% inhibitory concentrations (IC₅₀s) of dihydroartemisinin, mefloquine and lumefantrine were clustered in a relatively narrow, 3- to 6-fold range, whereas the IC₅₀ range of artesunate was 12-fold. We assessed the polymorphisms of candidate resistance genes pfcrt, pfmdr1, pfATP6, pfmdr6 and pfMT (a putative metabolite/drug transporter). The K76T mutation in pfcrt reached fixation in the study parasite population, whereas point mutations in pfmdr1 and pfATP6 had low levels of prevalence. In addition, pfmdr1 gene amplification was not detected. None of the mutations in pfmdr1 and pfATP6 was associated significantly with in vitro sensitivity to artemisinin derivatives. The ABC transporter gene pfmdr6 harbored two point mutations, two indels, and number variations in three simple repeats. Only the length variation in a microsatellite repeat appeared associated with altered sensitivity to dihydroartemisinin. The PfMT gene had two point mutations and one codon deletion; the I30N and N496- both reached high levels of prevalence. However, none of the SNPs or haplotypes in PfMT were correlated significantly with resistance to the four tested drugs. Compared with other parasite populations from the GMS, our studies revealed drastically different genotype and drug sensitivity profiles in parasites from the China-Myanmar border area, where artemisinins have been deployed extensively for over 30 years.
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Affiliation(s)
- Zenglei Wang
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Daniel Parker
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Hao Meng
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Parasitology, Kunming Medical University, Kunming, Yunnan, China
| | - Lanou Wu
- Department of Pharmacology, Kunming Medical University, Kunming, Yunnan, China
| | - Jia Li
- Department of Parasitology, Kunming Medical University, Kunming, Yunnan, China
| | - Zhen Zhao
- Department of Parasitology, Kunming Medical University, Kunming, Yunnan, China
| | - Rongping Zhang
- Department of Pharmaceutical Chemistry, Kunming Medical University, Kunming, Yunnan, China
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Haiyan Wang
- Department of Statistics, Kansas State University, Manhattan, Kansas, United States of America
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail: (LC); (ZY)
| | - Zhaoqing Yang
- Department of Parasitology, Kunming Medical University, Kunming, Yunnan, China
- * E-mail: (LC); (ZY)
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