在尼日利亚采用青蒿素为基础的联合疗法 11 年后，恶性疟原虫抗青蒿素基因无突变。

Absence of Plasmodium falciparum artemisinin resistance gene mutations eleven years after the adoption of artemisinin-based combination therapy in Nigeria.

机构信息

Institute for Tropical Medicine, Tübingen, Germany.

Department of Pharmaceutical Microbiology and Biotechnology, Nnamdi Azikiwe University, Awka, Nigeria.

出版信息

Malar J. 2021 Nov 10;20(1):434. doi: 10.1186/s12936-021-03968-9.

DOI:10.1186/s12936-021-03968-9

PMID:34758836

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC8579633/

Abstract

BACKGROUND

The occurrence of artemisinin resistance (ART)-associated polymorphism of Plasmodium falciparum K13-propeller (pfk13) gene before and after the introduction of artemisinin-based combination therapy (ACT) in two regions of Nigeria was investigated in this study. Regular surveillance is necessary to make a definite conclusion on the emergence and pattern of possible resistance to ART.

METHODS

This cross-sectional study was carried out in the Southwestern and Southeastern geopolitical zones of Nigeria. A total of 150, 217, and 475 participants were enrolled for the study in the Southwest (2004_Group A), Southwest (2015_Group B), and southeast (2015_Group C), respectively. Blood samples were collected from the study participants for DNA extraction and a nested PCR for P. falciparum identification. Samples that were positive for P. falciparum were genotyped for the pfk13 gene using the Sanger sequencing method. The single nucleotide polymorphisms were analysed using the Bioedit software.

RESULTS

A total of 116, 125, and 83 samples were positive for P. falciparum, respectively for the samples collected from the Southwest (2004 and 2015) and southeast (2015). Parasite DNA samples collected from febrile children in 2004 (Group A; n = 71) and 2015 (Group B; n = 73) in Osogbo Western Nigeria and 2015_Group C (n = 36) in southeast Nigeria were sequenced successfully. This study did not observe mutations associated with the in vitro resistance in southeast Asia, such as Y493H, R539T, I543T, and C580Y. Two new polymorphisms V520A and V581I were observed in two samples collected in Osogbo, Southwest Nigeria. These two mutations occurred in the year 2004 (Group A) before the introduction of ACT. Six mutations were identified in 17% of the samples collected in southeast Nigeria. One of these mutations (D547G) was non-synonymous, while the remaining (V510V, R515R, Q613Q, E688E, and N458N) were synonymous. Also, one (2%) heterozygote allele was identified at codon 458 in the 2015 (Group C) samples.

CONCLUSIONS

None of the mutations observed in this study were previously validated to be associated with ART resistance. These results, therefore, suggest that artemisinin is likely to remain highly effective in treating malaria in the study areas that are malarious zone.

摘要

背景

本研究调查了在尼日利亚两个地区引入青蒿素为基础的联合疗法（ACT）前后，恶性疟原虫 K13-螺旋桨（pfk13）基因与青蒿素耐药相关的多态性。为了明确可能出现的抗青蒿素耐药性的出现和模式，有必要进行定期监测。

方法

本横断面研究在尼日利亚西南部和东南部的两个地理政治区域进行。分别在西南部（2004_Group A）、西南部（2015_Group B）和东南部（2015_Group C）招募了 150、217 和 475 名参与者进行研究。从研究参与者采集血样进行 DNA 提取和巢式 PCR 鉴定恶性疟原虫。对 Pfk13 基因进行基因分型，使用 Sanger 测序法对 Pfk13 基因进行基因分型。使用 Bioedit 软件分析单核苷酸多态性。

结果

从西南部（2004 年和 2015 年）和东南部（2015 年）采集的发热儿童寄生虫 DNA 样本中，分别有 116、125 和 83 个样本对恶性疟原虫呈阳性。2004 年（Group A；n=71）和 2015 年（Group B；n=73）在奥索博西部尼日利亚和 2015_Group C（n=36）在东南部尼日利亚采集的样本成功进行了测序。本研究未观察到与体外抗药性相关的突变，如 Y493H、R539T、I543T 和 C580Y。在奥索博西南部采集的两个样本中观察到两个新的突变 V520A 和 V581I。这两个突变发生在 ACT 引入之前的 2004 年（Group A）。在东南部尼日利亚采集的 17%的样本中鉴定出 6 个突变。其中一个突变（D547G）是非同义突变，而其余（V510V、R515R、Q613Q、E688E 和 N458N）是同义突变。此外，在 2015 年（Group C）的样本中还鉴定出一个（2%）杂合子等位基因在 458 密码子。