Biochemistry and Molecular Biology Unit, Department of Basic Sciences, School of Medicine, University of Kinshasa, BP 190 KIN XI, Kinshasa, DR Congo.
Malar J. 2013 Dec 20;12:459. doi: 10.1186/1475-2875-12-459.
In 2001, the World Health Organization (WHO) has recommended the use of artemisinin-based combination therapy (ACT) as the first-line treatment of uncomplicated malaria cases, as monotherapies had become ineffective in many parts of the world. As a result, the Democratic Republic of Congo (DRC) withdrew chloroquine (CQ) from its malaria treatment policy in 2002 and an artesunate (AS)-amodiaquine (AQ) combination became the ACT of choice in DRC in 2005. AQ-resistance (AQR) has been reported in several parts of the world and mutations in codons 72-76 of the Plasmodium falciparum chloroquine-resistance transporter (pfcrt) gene have been strongly correlated with resistance, especially mutations encoding the SVMNT haplotype. This haplotype was first identified in Southeast Asia and South America but was recently reported in two African countries neighbouring DRC. These facts raised two questions: the first about the evolution of CQ resistance (CQR) in DRC and the second about the presence of the SVMNT haplotype, which would compromise the use of AQ as a partner drug for ACT.
A total of 213 thick blood films were randomly collected in 2010 from a paediatric clinic in Kinshasa, DRC. Microscopy controls and real-time polymerase chain reaction (RT-PCR) were performed for Plasmodium species identification. Haplotypes of the pfcrt gene were determined by sequencing.
The K76T mutation was detected in 145 out of 198 P. falciparum-positive samples (73.2%). In these 145 resistant strains, only the CVIET haplotype was detected.
This study is the first to assess the molecular markers of resistance to CQ and AQ after the introduction of ACT in DRC. The results suggest first that CQR is decreasing, as wild-type pfcrt haplotypes were found in only 26.8% of the samples and secondly that the SVMNT haplotype is not yet present in Kinshasa, suggesting that AQ remains valid as a partner drug for ACT in this region.
2001 年，世界卫生组织（WHO）建议使用青蒿素为基础的联合疗法（ACT）作为治疗无并发症疟疾的一线治疗方法，因为单药疗法在世界许多地方已经失效。因此，刚果民主共和国（DRC）于 2002 年从其疟疾治疗政策中撤出了氯喹（CQ），而青蒿琥酯-阿莫地喹（AS-AQ）组合成为 2005 年 DRC 的首选 ACT。在世界上的几个地区已经报道了 AQ 耐药性（AQR），并且疟原虫氯喹耐药转运蛋白（pfcrt）基因 72-76 密码子的突变与耐药性密切相关，特别是编码 SVMNT 单倍型的突变。这种单倍型最初在东南亚和南美洲被发现，但最近在与 DRC 接壤的两个非洲国家被报道。这些事实提出了两个问题：第一个是 DRC 中 CQ 耐药性（CQR）的演变，第二个是 SVMNT 单倍型的存在，这将危及 AQ 作为 ACT 联合用药的使用。
2010 年，从 DRC 金沙萨的一家儿科诊所随机采集了 213 份厚血涂片。进行了显微镜检查对照和实时聚合酶链反应（RT-PCR）以鉴定疟原虫种。通过测序确定了 pfcrt 基因的单倍型。
在 198 个疟原虫阳性样本中的 145 个（73.2%）中检测到 K76T 突变。在这些 145 株耐药株中，仅检测到 CVIET 单倍型。
这项研究是在 DRC 引入 ACT 后首次评估 CQ 和 AQ 耐药的分子标记物。结果表明，首先 CQR 正在下降，因为只有 26.8%的样本中发现了野生型 pfcrt 单倍型，其次 SVMNT 单倍型尚未在金沙萨出现，这表明在该地区 AQ 仍然是 ACT 的有效联合用药。
