title: Emergence of sulfadoxine-pyrimethamine resistance in Indian isolates of Plasmodium falciparum in the last two decades.
abstract: Genotyping the sulfadoxine-pyrimethamine (SP) genes will help in identifying the genes under drug selection and the emergence of resistance in dhfr and dhps genes. India is an important hotspot for studying malaria due to the immense climatic diversity prevalent in the country. The central and eastern parts of the country are most vulnerable sites where malaria cases are reported throughout the year. From different regions of the country 173 field isolates were genotyped at various loci in dhfr and dhps genes collected between 1994 and 2013. This encompasses the period before antimalarial resistance emerged and the period after the use of combination therapy was made mandatory in the country. We observed the rise of resistant SP alleles from very low frequencies (in the year 1994) to steadily rising (in the year 2000) and maintaining this increasing trend subsequently (in the year 2013) as shown by the sequence analysis of dhfr and dhps genes. This study assessed the prevalence of mutations in dhfr and dhps genes associated with SP resistance in samples indicative of increase in resistance levels of Plasmodium falciparum to SP even after the change in malaria treatment policy in the country.
authors: National Institute of Malaria Research, Sector-8 Dwarka, New Delhi 110077, India.
authors: Amit
authors: A
authors: Kumar
authors: National Institute of Malaria Research, Sector-8 Dwarka, New Delhi 110077, India.
authors: Romilla
authors: R
authors: Moirangthem
authors: Department of Biotechnology, Chaudhary Devi Lal University, Haryana 125055, India.
authors: Suresh Kumar
authors: SK
authors: Gahlawat
authors: Department of Pediatrics, Lady Hardinge Medical College and Kalawati Saran Children's Hospital, New Delhi-110001, India.
authors: Jagdish
authors: J
authors: Chandra
authors: National Institute of Malaria Research, Sector-8 Dwarka, New Delhi 110077, India.
authors: Purva
authors: P
authors: Gupta
authors: National Institute of Malaria Research, Sector-8 Dwarka, New Delhi 110077, India.
authors: Neena
authors: N
authors: Valecha
authors: National Institute of Malaria Research, Sector-8 Dwarka, New Delhi 110077, India.
authors: Anup
authors: A
authors: Anvikar
authors: National Institute of Malaria Research, Sector-8 Dwarka, New Delhi 110077, India. Electronic address: vineetas_2000@yahoo.com.
authors: Vineeta
authors: V
authors: Singh
mesh_terms: D000962:Antimalarials / Q000494:pharmacology*; D004094:Dihydropteroate Synthase / Q000235:genetics; D004338:Drug Combinations; D004351:Drug Resistance / Q000235:genetics*; D006801:Humans; D007194:India; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000469:parasitology*; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D015995:Prevalence; D015800:Protozoan Proteins / Q000235:genetics; D011739:Pyrimethamine / Q000494:pharmacology*; D013413:Sulfadoxine / Q000494:pharmacology*; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics
chemical_list: D000962:Antimalarials; D004338:Drug Combinations; D015800:Protozoan Proteins; C001205:fanasil, pyrimethamine drug combination; D013413:Sulfadoxine; D013762:Tetrahydrofolate Dehydrogenase; D004094:Dihydropteroate Synthase; D011739:Pyrimethamine
keywords: Drug resistance; Mutations; P. falciparum; dhfr and dhps genes