云南边境地区氯喹及与青蒿琥酯伍用治疗前后恶性疟原虫pfcrt 和pfmdr1抗药性有关基因点突变的变化特征

目的　了解氯喹单用及与青蒿琥脂伍用治疗恶性疟前后 ,pfcrt和 pfmdr1抗药性有关基因的点突变变化特征。　 方法　使用PCR RFLP技术检测基因点突变。　结果　氯喹及与青蒿琥脂伍用治疗前后的所有样本都发现有恶性疟原虫pfcrt基因氨基酸编码 76突变为苏氨酸的特征。但是 ,氯喹治疗前 ,5 0 % pfmdr1基因氨基酸编码 86为天冬酰氨酸 (野生型 ) ,而剩余的 5 0 %为野生型和突变型 (苏氨酸 )的特征。氯喹治疗后 ,在 18个复燃的病例中 ,83 .3 %的 pfmdr1基因 86位点为野生型 ,剩余的 16.7%是混合型。氯喹与青蒿琥脂伍用治疗前 ,3个样本携带混合型基因型 ,剩余的 (86% )为野生型 ,但治疗后 ,所有样本只携带野生型。　结论　这些结果可能支持这样的假说 :pfcrt基因突变起主导作用 ,但 pfmdr1基因突变增强了氯喹抗药性的效果。

CHANGES ON POINT MUTATIONS OF pfmdr1- T86N AND pfcrt-T76K GENE IN PRE- AND POST-TREATMENT OF CHLOROQUINE AND ARTESUNATE IN BORDER AREAS

Objective To assess chloroquine (CQ) monotherapy and chloroquine+artesunate (CQ+ART) combined regimen in falciparum infection and characterized the isolates for pfcrt (76 K>T ) and pfmdr 1 (86 N>T ) changes. Methods Using PCR-RFLPs examined pfcrt and pfmdr 1 point mutations. Results Before and after CQ/CQ+AT treatment, mutant pfcrt 76 T was harboured by all (100%) samples, and no changes. However, before CQ treatment, 50% of these pre-treatment samples carried wild type pfmdr 1 86 N while the remaining 50% had mixed (86 N/T ) genotypes. After CQ treatment, 83.3% (15) of these 18 recrudescent samples had pfmdr 1 86 N and the remaining 16.7% (3/18) carried 86 N/T mixed genotypes. Before CQ+ART treatment, 3 of these pre-treatment samples had mixed mutant and wild type pfmdr 1, the rest (86%) had wild type only. Of the CQ+ART treatment failures, all these samples carried wild type pfmdr 1. Conclusion This demonstrates the supremacy of pfcrt codon 76 mutation and support the view that changes in this gene may be the primary determinant of CQ resistance.