Analysis of gene mutations involved in chloroquine resistance in Plasmodium faIdparum parasites isolated from patients in the southwest of Saudi Arabia

ABSTRACT

Chloroquine has been the drug of choice for the treatment of malaria for many decades. We aimed to examine the molecular basis of chloroquine resistance among Plasmodium falciparum isolates from the southwestern region of Saudi Arabia by analyzing the K76T and N86Y mutations in the PfCRT and PfMDR1 genes, respectively. P falciparum-infected blood spot samples [n=121] were collected on filter papers. DMA was extracted and fragments from the above genes were amplified using nested PCR. The amplicons were digested by Apol enzyme and sequenced. Of the 121 samples, 95 and 112 samples could be amplified for PfCRT K76T and PfMDR1 N86Y mutations, respectively. All of the samples amplified for the PfCRT K76T mutation were undigestible by Apol, suggesting the presence of the K76T mutation. For the PfMDR1 N86Y mutation, 65/109 samples [59.6%] were digestible when treated with Apol in a pattern, suggestive of the presence of the investigated wild allele [N86]. However, 44/109 samples [40.4%] were digestible by Apol, suggesting the presence of the mutated allele [Y] at position 86. DMA sequencing confirmed these results. Surprisingly, all isolates exhibited the mutated allele at codon 76 [K76T] of PfCRT. However, the mutated mutant allele at codon 86 [N86Y] of PfMDR1 was found in 40.4% of the samples studied. To our knowledge, this is the first study that has investigated the existence of the mutation in the PfMDR1 gene in the country. This study will contribute to the development of new strategies for therapeutic intervention against malaria in Saudi Arabia