肯尼亚基苏木县尼亚永地区与不同抗疟药物耐药性相关的疟原虫基因突变流行情况。

Prevalence of mutations in Plasmodium falciparum genes associated with resistance to different antimalarial drugs in Nyando, Kisumu County in Kenya.

机构信息

Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya; Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya.

Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya.

出版信息

Infect Genet Evol. 2020 Mar;78:104121. doi: 10.1016/j.meegid.2019.104121. Epub 2019 Nov 19.

DOI:10.1016/j.meegid.2019.104121

PMID:31756512

Abstract

Resistance to the mainstay antimalarial drugs is a major concern in the control of malaria. Delayed Plasmodium falciparum parasite clearance has been associated with Single Nucleotide Polymorphisms (SNPs) in the kelch propeller region (K13). However, SNPs in the Pf-adaptor protein complex 2 mu subunit (Pfap2-mu), Pfcrt and Pfmdr1 are possible markers associated with multi-drug resistance. Here, we explored the prevalence of SNPs in the K13, Pfap2-mu, Pfcrt, and Pfmdr1 in 94 dried blood spot field isolates collected from children aged below 12 years infected with P. falciparum during a cross-sectional study. The samples were collected in 2015 during the peak malaria transmission season in the Nyando region of Western Kenya before treatment with Artemether-Lumefantrine, the first-line artemisinin-based combination therapy (ACT) in Kenya. However, 47 of the 94 samples had recurrent parasitemia and were interrogated for the presence of the SNPs in K13 and Pfap2-mu. We used PCR amplification and sequencing to evaluate specific regions of K13 (codons 432-702), Pfap2-mu (codons 1-350), Pfmdr1 (codons 86, 1034-1246), and Pfcrt (codons 72-76) gene(s). The majority of parasites harbored the wild type K13 sequence. However, we found a unique non-synonymous W611S change. In silico studies on the impact of the W611S predicted structural changes in the overall topology of the K13 protein. Of the 47 samples analyzed for SNPs in the Pfap2-mu gene, 14 (29%) had S160 N/T mutation. The CVIET haplotype associated with CQ resistance in the Pfcrt yielded a 7.44% (7/94), while CVMNK haplotype was at 92.56%. Mutations in the Pfmdr1 region were detected only in three samples (3/94; 3.19%) at codon D1246Y. Our data suggest that parasites in the western part of Kenya harbor the wildtype strains. However, the detection of the unique SNP in K13 and Pfap2-mu linked with ACT delayed parasite clearance may suggest slow filtering of ACT-resistant parasites.

摘要

抗疟药的主要药物的耐药性是疟疾控制的主要关注点。疟原虫清除延迟与kelch 推进器区域（K13）的单核苷酸多态性（SNP）有关。然而，Pf-adaptor 蛋白复合物 2 mu 亚基（Pfap2-mu）、Pfcrt 和 Pfmdr1 中的 SNP 可能是与多药耐药性相关的标记物。在这里，我们在 94 个从感染恶性疟原虫的 12 岁以下儿童中采集的干血斑现场分离株中研究了 K13、Pfap2-mu、Pfcrt 和 Pfmdr1 中的 SNP 流行情况。这些样本是 2015 年在肯尼亚西部 Nyando 地区疟疾传播高峰期采集的，当时使用了青蒿琥酯-咯萘啶，这是肯尼亚的一线青蒿素为基础的联合治疗（ACT）。然而，94 个样本中有 47 个出现了复发性寄生虫血症，并对 K13 和 Pfap2-mu 中 SNP 的存在进行了检测。我们使用 PCR 扩增和测序来评估 K13（密码子 432-702）、Pfap2-mu（密码子 1-350）、Pfmdr1（密码子 86、1034-1246）和 Pfcrt（密码子 72-76）基因的特定区域。大多数寄生虫携带野生型 K13 序列。然而，我们发现了一个独特的非同义 W611S 变化。对 W611S 预测的 K13 蛋白整体拓扑结构变化的计算机模拟研究。在对 Pfap2-mu 基因中的 SNP 进行分析的 47 个样本中，有 14 个（29%）存在 S160N/T 突变。与 CQ 耐药性相关的 CVIET 单倍型在 Pfcrt 中产生了 7.44%（7/94），而 CVMNK 单倍型为 92.56%。在 Pfmdr1 区域只检测到三个样本（3/94；3.19%）中的 D1246Y 密码子突变。我们的数据表明，肯尼亚西部的寄生虫携带野生型菌株。然而，K13 和 Pfap2-mu 中与 ACT 相关的延迟寄生虫清除的独特 SNP 的检测可能表明 ACT 耐药性寄生虫的过滤缓慢。