The loss of chloroquine (CQ) effectiveness has led to its withdrawal from national policies as a first-line treatment for uncomplicated malaria in several endemic countries, such as the Democratic Republic of Congo (DRC). The K76T mutation on the pfcrt gene has been identified as a marker of CQ resistance and the SVMNT haplotype in codons 72–76 on the same gene has been associated with resistance to amodiaquine (AQ). In the DRC, the prevalence of K76T has decreased from 100% in 2000 to 63.9% in 2014. The purpose of this study was to determine the prevalence of K76T mutations in circulating strains of Plasmodium falciparum, 16 years after CQ withdrawal in the DRC and to investigate the presence of the SVMNT haplotype. In 2017, ten geographical sites across the DRC were selected. Dried blood samples were collected from patients attending health centres. Malaria was first detected by a rapid diagnostic test (RDT) available on site (SD Bioline Malaria Ag Pf or CareStart Malaria Pf) or thick blood smear and then confirmed by a P. falciparum species-specific real-time PCR assay. A pfcrt gene segment containing a fragment that encodes amino acids at positions 72–76 was amplified by conventional PCR before sequencing. A total of 1070 patients were enrolled. Of the 806 PCR-confirmed P. falciparum positive samples, 764 were successfully sequenced. The K76T mutation was detected in 218 samples (28.5%; 95% CI 25.4%–31.9%), mainly (96%) with the CVIET haplotype. Prevalence of CQ resistance marker was unequally distributed across the country, ranging from 1.5% in Fungurume to 89.5% in Katana. The SVMNT haplotype, related to AQ resistance, was not detected. Overall, the frequency of the P. falciparum CQ resistance marker has decreased significantly and no resistance marker to AQ was detected in the DRC in 2017. However, the between regions variability of CQ resistance remains high in the country. Further studies are needed for continuous monitoring of the CQ resistance level for its prospective re-use in malaria management. The absence of the AQ resistance marker is in line with the use of this drug in the current DRC malaria treatment policy.

中文翻译：

---

刚果民主共和国抗疟疾药物耐药性的分子监测：氯喹抗药性高变异性和缺乏氨二醌抗药性

氯喹（CQ）有效性的丧失已导致其从国家政策中退出，成为一些流行国家如刚果民主共和国（DRC）中无并发症疟疾的一线治疗方法。pfcrt基因上的K76T突变已被鉴定为CQ抗性的标志物，同一基因上第72-76位密码子的SVMNT单倍型与对阿莫地喹（AQ）的抗性相关。在刚果（金）中，K76T的患病率从2000年的100％下降到2014年的63.9％。本研究的目的是确定在CRC退出DRC后16年，恶性疟原虫循环株中K76T突变的患病率。调查SVMNT单倍型的存在。2017年，刚果民主共和国选出了十个地理位置。从参加保健中心的患者那里采集干血样品。首先通过现场可用的快速诊断测试（RDT）（SD Bioline疟疾Ag Pf或CareStart疟疾Pf）或浓血涂片检测疟疾，然后通过恶性疟原虫物种特异性实时PCR测定法进行确认。在测序之前，通过常规PCR扩增了一个pfcrt基因区段，该区段包含一个编码72-76位氨基酸的片段。总共招募了1070名患者。在806个PCR确认的恶性疟原虫阳性样品中，成功测序了764个。在218个样本中检测到K76T突变（28.5％； 95％CI 25.4％–31.9％），主要（96％）为CVIET单倍型。CQ抗性标记的流行在全国范围内分布不均，从Fungurume的1.5％到Katana的89.5％。SVMNT单倍型 未检测到与AQ抗性相关的信息。总体而言，恶性疟原虫CQ抗药性标记的频率已显着降低，2017年在刚果民主共和国未发现对AQ的抗药性标记。但是，该国CQ抗药性之间的区域差异仍然很大。需要进行进一步的研究，以持续监测CQ耐药水平，以便将其用于疟疾管理中。在目前的DRC疟疾治疗政策中，缺少AQ抗药性标志与该药的使用相符。需要进行进一步的研究，以持续监测CQ耐药水平，以便将其用于疟疾管理中。在目前的DRC疟疾治疗政策中，缺少AQ抗药性标志与该药的使用相符。需要进行进一步的研究，以持续监测CQ耐药水平，以便将其用于疟疾管理中。在目前的DRC疟疾治疗政策中，缺少AQ抗药性标志与该药的使用相符。