title: Molecular evidence of increased resistance to anti-folate drugs in Plasmodium falciparum in North-East India: a signal for potential failure of artemisinin plus sulphadoxine-pyrimethamine combination therapy.
abstract: North-east India, being a corridor to South-east Asia, is believed to play an important role in transmitting drug resistant Plasmodium falciparum malaria to India and South Asia. North-east India was the first place in India to record the emergence of drug resistance to chloroquine as well as sulphadoxine/pyrimethamine. Presently chloroquine resistance is widespread all over the North-east India and resistance to other anti-malarials is increasing. In this study both in vivo therapeutic efficacy and molecular assays were used to screen the spectrum of drug resistance to chloroquine and sulphadoxine/pyrimethamine in the circulating P. falciparum strains. A total of 220 P. falciparum positives subjects were enrolled in the study for therapeutic assessment of chloroquine and sulphadoxine/pyrimethamine and assessment of point mutations conferring resistances to these drugs were carried out by genotyping the isolates following standard methods. Overall clinical failures in sulphadoxine/pyrimethamine and chloroquine were found 12.6 and 69.5% respectively, while overall treatment failures recorded were 13.7 and 81.5% in the two arms. Nearly all (99.0%) the isolates had mutant pfcrt genotype (76 T), while 68% had mutant pfmdr-1 genotype (86 Y). Mutation in dhps 437 codon was the most prevalent one while dhfr codon 108 showed 100% mutation. A total of 23 unique haplotypes at the dhps locus and 7 at dhfr locus were found while dhps-dhfr combined loci revealed 49 unique haplotypes. Prevalence of double, triple and quadruple mutations were common while 1 haplotype was found with all five mutated codons (F/AGEGS/T) at dhps locus. Detection of quadruple mutants (51 I/59 R/108 N/164 L) in the present study, earlier recorded from Car Nicobar Island, India only, indicates the presence of high levels of resistance to sulphadoxine/pyrimethamine in north-east India. Associations between resistant haplotypes and the clinical outcomes and emerging resistance in sulphadoxine/pyrimethamine in relation to the efficacy of the currently used artemisinin combination therapy are discussed.
authors.affiliation: Regional Medical Research Centre, NE Region (ICMR), Dibrugarh, Assam, India.
authors.forename: Pradyumna Kishore
authors.initials: PK
authors.lastname: Mohapatra
authors.affiliation: Regional Medical Research Centre, NE Region (ICMR), Dibrugarh, Assam, India.
authors.forename: Devojit Kumar
authors.initials: DK
authors.lastname: Sarma
authors.affiliation: Regional Medical Research Centre, NE Region (ICMR), Dibrugarh, Assam, India; National Institute for Research in Environmental Health (ICMR), Kamla Nehru Hospital Building, Gandhi Medical College Campus, Bhopal, Madhya Pradesh, India.
authors.forename: Anil
authors.initials: A
authors.lastname: Prakash
authors.affiliation: Regional Medical Research Centre, NE Region (ICMR), Dibrugarh, Assam, India.
authors.forename: Khukumoni
authors.initials: K
authors.lastname: Bora
authors.affiliation: Regional Medical Research Centre, NE Region (ICMR), Dibrugarh, Assam, India.
authors.forename: Md Atique
authors.initials: MA
authors.lastname: Ahmed
authors.affiliation: Regional Medical Research Centre, NE Region (ICMR), Dibrugarh, Assam, India.
authors.forename: Bibhas
authors.initials: B
authors.lastname: Sarma
authors.affiliation: Regional Medical Research Centre, NE Region (ICMR), Dibrugarh, Assam, India.
authors.forename: Basanta Kumar
authors.initials: BK
authors.lastname: Goswami
authors.affiliation: Regional Medical Research Centre, NE Region (ICMR), Dibrugarh, Assam, India.
authors.forename: Dibya Ranjan
authors.initials: DR
authors.lastname: Bhattacharyya
authors.affiliation: Regional Medical Research Centre, NE Region (ICMR), Dibrugarh, Assam, India.
authors.forename: Jagadish
authors.initials: J
authors.lastname: Mahanta
mesh_terms: D000293:Adolescent; D000328:Adult; D000962:Antimalarials / Q000627:therapeutic use*; D037621:Artemisinins / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D002738:Chloroquine / Q000627:therapeutic use; D003062:Codon; D004338:Drug Combinations; D004351:Drug Resistance / Q000235:genetics*; D004359:Drug Therapy, Combination; D005260:Female; D006239:Haplotypes; D006801:Humans; D007194:India / Q000453:epidemiology; D016778:Malaria, Falciparum / Q000188:drug therapy* / Q000453:epidemiology / Q000469:parasitology; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics; D008875:Middle Aged; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics; D009154:Mutation; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D015800:Protozoan Proteins / Q000235:genetics; D011739:Pyrimethamine / Q000627:therapeutic use*; D013413:Sulfadoxine / Q000627:therapeutic use*
chemical_list: D000962:Antimalarials; D037621:Artemisinins; D002738:Chloroquine; D003062:Codon; D004338:Drug Combinations; D026901:Membrane Transport Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D015800:Protozoan Proteins; D011739:Pyrimethamine; D013413:Sulfadoxine; C513498:Mdr1 protein, Plasmodium falciparum; C416369:PfCRT protein, Plasmodium falciparum; C001205:fanasil, pyrimethamine drug combination; C031327:artemisinin