BACKGROUND: Anti-malarial resistance in @entity3964 remains an obstacle for @entity311 control. Resistance-associated genes were analysed in Brazilian samples over four decades to evaluate the impact of different treatment regimens on the parasite genetic profile. METHODS: Samples were collected on filter paper from @entity1 infected in the Amazon region from 1984 to 2011. DNA was extracted with Chelex   100 and monoinfection confirmed by PCR. SNPs in the pfcrt, pfmdr1, pfdhfr and pfdhps genes were assessed by PCR-RFLP. The pfmdr1 copy number was estimated using real time quantitative PCR with SYBR   Green. Parasite response was assessed ex vivo with seven concentrations of each anti-malarial. @entity1 were treated according to Brazilian guidelines: @entity4807 plus @entity803 or @entity8775 in period 1 and ACT in @entity5394 . RESULTS: All 96 samples presented the pfcrt 76T mutant throughout the assessed periods. In addition, all isolates showed ex vivo @entity503 resistance. The pfmdr1 86Y was detected in 1.5% of samples in period 1, and in 25% in @entity5394 . All samples presented the pfmdr1 1246Y. The analysis of pfmdr1 copy number showed amplification in 37.3% in period 1 and in 42% in @entity5394 . Mutations in pfdhfr were shown as follows: 51I in all samples in period 1 and in 81.2% in @entity5394 ; 59R in 6.4% in @entity5394 . The pfdhfr 108N and the pfdhps 437G were seen in all samples along time; the pfdhps 540E in 93.7% in period 1 and in 75% in @entity5394 . CONCLUSIONS: The 76T mutation associated to @entity503 resistance is still present in the parasite population, although this anti-malarial was withdrawn from the chemotherapy of @entity3964 in Brazil in the mid-1980s. All isolates assayed ex vivo for @entity503 showed resistant phenotype and 76T. No association was observed between pfmdr1 mutations and resistance to @entity4807 , @entity8775 and @entity507 derivatives. Additionally, the pfdhfr 108N mutation was detected in all samples throughout the evaluated periods, demonstrating fixation of the mutant allele in the parasite population. Changes in Brazilian national guidelines for the @entity311 chemotherapy in the last 27 years yielded a discreet genetic impact in the parasite population.

Analysis of polymorphisms in XXXX genes related to drug resistance: a survey over four decades under different treatment policies in Brazil.

@entity1 :: ('9606', 'Species') :: ['Patients', 'patients'] @entity5394 :: ('8864', 'Gene') :: ['period 2'] @entity8775 :: ('MESH:D015767', 'Chemical') :: ['mefloquine'] @entity4807 :: ('MESH:D011803', 'Chemical') :: ['quinine'] @entity507 :: ('MESH:C031327', 'Chemical') :: ['artemisinin'] @entity3964 :: ('5833', 'Species') :: ['P. falciparum', 'Plasmodium falciparum'] @entity311 :: ('MESH:D008288', 'Disease') :: ['malaria'] @entity503 :: ('MESH:D002738', 'Chemical') :: ['chloroquine'] @entity803 :: ('MESH:D013752', 'Chemical') :: ['tetracycline']
@entity3964 :: (5833,Species) :: ['Plasmodium falciparum']
