Use of molecular beacons to detect an antifolate resistance-associated mutation in Plasmodium falciparum. Antimicrobial Agents Chemother

A PCR-based technique using new fluorescent probes, called molecular beacons, was developed to detect the antifolate resistance-associated S108N point mutation in Plasmodium falciparum. One hundred African clinical isolates were tested by the new method in comparison with the PCR-restriction fragment length polymorphism method. This new molecular technique appears to be a promising tool for epidemiological studies. The spread of chloroquine-resistant Plasmodium falciparum strains in many areas of malaria endemicity has required the use of other drugs for malaria treatment and prophylaxis (3). Pyrimethamine and proguanil, which are specific competitive inhibitors of dihydrofolate reductase (DHFR) (9), are cur-rently given by clinicians in combination with other antimalar-ial agents, such as sulfadoxine, chloroquine, and, recently, atovaquone (11). Because antifolate-resistant P. falciparum strains have been reported since the 1950s, when antifolates were introduced as single antimalarial treatments (14), moni-toring antifolate susceptibility appears to be essential. Durin