title: Prevalence of crt and mdr-1 mutations in Plasmodium falciparum isolates from Grande Comore island after withdrawal of chloroquine.
abstract: In Comoros, the widespread of chloroquine (CQ)-resistant Plasmodium falciparum populations was a major obstacle to malaria control, which led to the official withdrawal of CQ in 2004. Continuous monitoring of CQ-resistant markers of the P. falciparum CQ resistant transporter (pfcrt) and the P. falciparum multiple drug resistance 1 (pfmdr-1) is necessary inder to obtain first-hand information on CQ susceptibility of parasite populations in the field. The objective of this study is to assess the prevalence and evolution of CQ-resistance in the P. falciparum populations on the Comoros' Grande Comore island after withdrawal of CQ.
  
  
  
  A total of 207 P. falciparum clinical isolates were collected from the island, including 118 samples from 2006 to 2007 and 89 samples from 2013 to 2014. Nucleotide substitutions in the pfcrt and pfmdr-1 genes linked to CQ response in parasite isolates were assessed using nested PCR and DNA sequencing.
  
  
  
  From the pfcrt gene segment sequenced, we detected C72S, M74I, N75E, and K76T substitutions in the parasite isolates collected from both 2006-2007 to 2013-2014 periods. Significant decline of pfcrt resistant alleles at C72S (42.6 to 6.9 %), M74I (39.1 to 14.9 %), N75E (63.5 to 18.3 %), and K76T (72.2 to 19.5 %) from 2006-2007 to 2013-2014 were observed, and the frequency of pfcrt wild type allele was significantly increased from 19.1 % in 2006-2007 to 75.8 % in 2013-2014. Sequence analysis of pfmdr-1 also detected point mutations at codons N86Y, Y184F, and D1246Y, but not S1034C and N1042D, in the isolates collected from both examined periods. An increasing trend in the prevalence of the pfmdr-1 wild type allele (NYD, 4.3 % in 2006-2007; and 28.7 % in 2013-2014), and a decreasing trend for pfmdr-1 N86Y mutation (87.0 % in 2006-2007; and 40.2 % in 2013-2014) were observed in our samples.
  
  
  
  The present data indicate that the prevalence and patterns of mutant pfcrt and pfmdr-1 dramatically decreased in the Grande Comore isolates from 2006 to 2014, suggesting that the CQ-sensitive P. falciparum strains have returned after the withdrawal of CQ. The data also suggests that the parasites with wild type pfcrt/pfdmr-1 genes may have growth and/or transmission advantages over the mutant parasites. The information obtained from this study will be useful for developing and updating anti-malarial treatment policy in Grande Comore island.
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Huang
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China.
authors.forename: Changsheng
authors.initials: C
authors.lastname: Deng
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Wang
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yang
authors.affiliation: School of Medicine, Jinan University, Guangzhou, 510632, Guangdong, People's Republic of China.
authors.forename: Shiguang
authors.initials: S
authors.lastname: Huang
authors.affiliation: Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.|State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, 361005, Fujian, People's Republic of China.
authors.forename: Xin-Zhuan
authors.initials: XZ
authors.lastname: Su
authors.affiliation: The First Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China.
authors.forename: Yajun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Guangdong Newsouth Artepharm Co., Ltd, Guangzhou, 510405, Guangdong, People's Republic of China.
authors.forename: Longhua
authors.initials: L
authors.lastname: Pan
authors.affiliation: Guangdong Newsouth Artepharm Co., Ltd, Guangzhou, 510405, Guangdong, People's Republic of China.
authors.forename: Guoming
authors.initials: G
authors.lastname: Li
authors.affiliation: Guangdong Newsouth Artepharm Co., Ltd, Guangzhou, 510405, Guangdong, People's Republic of China.
authors.forename: Di
authors.initials: D
authors.lastname: Li
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China.
authors.forename: Hongying
authors.initials: H
authors.lastname: Zhang
authors.affiliation: National Malaria Control Programme, BP 500, Moroni, Union of Comoros.
authors.forename: Afane
authors.initials: A
authors.lastname: Bacar
authors.affiliation: National Malaria Control Programme, BP 500, Moroni, Union of Comoros.
authors.forename: Kamal Said
authors.initials: KS
authors.lastname: Abdallah
authors.affiliation: National Malaria Control Programme, BP 500, Moroni, Union of Comoros.
authors.forename: Rachad
authors.initials: R
authors.lastname: Attoumane
authors.affiliation: Ministry of Health Comoros, BP 403, Moroni, Union of Comoros.
authors.forename: Ahamada M S A
authors.initials: AM
authors.lastname: Mliva
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China.
authors.forename: Shaoqin
authors.initials: S
authors.lastname: Zheng
authors.affiliation: Research Institute of Tropical Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Xu
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, Guangdong, People's Republic of China.
authors.forename: Fangli
authors.initials: F
authors.lastname: Lu
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China. gyz111@hotmail.com.
authors.forename: Yezhi
authors.initials: Y
authors.lastname: Guan
authors.affiliation: Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China. songjpgz@sina.com.
authors.forename: Jianping
authors.initials: J
authors.lastname: Song
mesh_terms: D000328:Adult; D019943:Amino Acid Substitution; D000962:Antimalarials / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D002738:Chloroquine / Q000494:pharmacology*; D017507:Comoros / Q000453:epidemiology; D004363:Drug Utilization; D005260:Female; D006801:Humans; D016778:Malaria, Falciparum / Q000453:epidemiology* / Q000469:parasitology; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics*; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics*; D020125:Mutation, Missense; D010963:Plasmodium falciparum / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D015995:Prevalence; D015800:Protozoan Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D000962:Antimalarials; D002738:Chloroquine; D026901:Membrane Transport Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D015800:Protozoan Proteins; C513498:Mdr1 protein, Plasmodium falciparum; C416369:PfCRT protein, Plasmodium falciparum
keywords: Chloroquine resistance; Comoros; Plasmodium falciparum; pfcrt; pfmdr-1