Plasmodium falciparum and Dihydrofolate Reductase I164L Mutations in Africa

摘要: The paper by Ochong et al. modifies the real-time PCR method we published previously and applies it to samples from Malawi, Zambia, Thailand (2, 7). These authors bring up several criticisms of original technique, welcome this opportunity clarify concerns about method. We would also like comment on some their conclusions. The primary criticism our assay mutations dihydrofolate reductase at position 164 (DHFR-164) is that there was nonspecific binding probes. have reported phenomenon (1), which evident describing MGB probe (see Fig. 4 in reference 5). However, background does not interfere with assay's discriminating ability as long proper controls (standard curves both wild-type mutant DNA concentrations similar clinical samples) are included (1, 2). In addition, performance dependent machine, reagents, even batch (1). Thus, should be reoptimized when adapted different conditions. Overall, find modified a successful adaptation new lab. incompletely validated. For example, did determine its sensitivity specificity running gold standard allele-specific same samples. Also, address possibility whole-genome amplification changes frequencies haplotypes sample. There much stronger body evidence supporting emergence DHFR-164L mutation Africa than suggested paper. recently confirmed existence Malawi heteroduplex tracking direct sequencing (4). Furthermore, subsequent report Lynch found 14% southwestern Uganda collected 2005 (6). Previously, 2002, had been prevalence 1.25% Kanungu (3). This suggests may emerging regionally Africa. Finally, important note all studies use patients enrolled were sampled represent general population. small differences between study sites expected.