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来自高、低疟疾传播地区的无并发症恶性疟原虫临床分离株在埃塞俄比亚西部显示出明显的 pfcrt 和 pfmdr1 多态性。

Clinical isolates of uncomplicated falciparum malaria from high and low malaria transmission areas show distinct pfcrt and pfmdr1 polymorphisms in western Ethiopia.

机构信息

Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.

Medical Research Council Unit the Gambia, London School of Hygiene and Tropical Medicine, Banjul, Gambia.

出版信息

Malar J. 2023 Jun 3;22(1):171. doi: 10.1186/s12936-023-04602-6.

DOI:10.1186/s12936-023-04602-6

PMID:37270589

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10239113/

Abstract

BACKGROUND

Pfcrt gene has been associated with chloroquine resistance and the pfmdr1 gene can alter malaria parasite susceptibility to lumefantrine, mefloquine, and chloroquine. In the absence of chloroquine (CQ) and extensive use of artemether-lumefantrine (AL) from 2004 to 2020 to treat uncomplicated falciparum malaria, pfcrt haplotype, and pfmdr1 single nucleotide polymorphisms (SNPs) were determined in two sites of West Ethiopia with a gradient of malaria transmission.

METHODS

230 microscopically confirmed P. falciparum isolates were collected from Assosa (high transmission area) and Gida Ayana (low transmission area) sites, of which 225 of them tested positive by PCR. High-Resolution Melting Assay (HRM) was used to determine the prevalence of pfcrt haplotypes and pfmdr1 SNPs. Furthermore, the pfmdr1 gene copy number (CNV) was determined using real-time PCR. A P-value of less or equal to 0.05 was considered significant.

RESULTS

Of the 225 samples, 95.5%, 94.4%, 86.7%, 91.1%, and 94.2% were successfully genotyped with HRM for pfcrt haplotype, pfmdr1-86, pfmdr1-184, pfmdr1-1042 and pfmdr1-1246, respectively. The mutant pfcrt haplotypes were detected among 33.5% (52/155) and 80% (48/60) of isolates collected from the Assosa and Gida Ayana sites, respectively. Plasmodium falciparum with chloroquine-resistant haplotypes was more prevalent in the Gida Ayana area compared with the Assosa area (COR = 8.4, P = 0.00). Pfmdr1-N86Y wild type and 184F mutations were found in 79.8% (166/208) and 73.4% (146/199) samples, respectively. No single mutation was observed at the pfmdr1-1042 locus; however, 89.6% (190/212) of parasites in West Ethiopia carry the wild-type D1246Y variants. Eight pfmdr1 haplotypes at codons N86Y-Y184F-D1246Y were identified with the dominant NFD 61% (122/200). There was no difference in the distribution of pfmdr1 SNPs, haplotypes, and CNV between the two study sites (P > 0.05).

CONCLUSION

Plasmodium falciparum with the pfcrt wild-type haplotype was prevalent in high malaria transmission site than in low transmission area. The NFD haplotype was the predominant haplotype of the N86Y-Y184F-D1246Y. A continuous investigation is needed to closely monitor the changes in the pfmdr1 SNPs, which are associated with the selection of parasite populations by ACT.

摘要

背景

Pfcrt 基因与氯喹耐药性有关，pfmdr1 基因可以改变疟原虫对青蒿琥酯、甲氟喹和氯喹的敏感性。在缺乏氯喹（CQ）和 2004 年至 2020 年广泛使用青蒿琥酯-咯萘啶（AL）治疗无并发症恶性疟原虫疟疾的情况下，在埃塞俄比亚西部两个疟疾传播梯度的地点确定了 pfcrt 单倍型和 pfmdr1 单核苷酸多态性（SNP）。

方法

从 Assosa（高传播区）和 Gida Ayana（低传播区）采集了 230 例经显微镜确认的 P. falciparum 感染样本，其中 225 例通过 PCR 检测呈阳性。高分辨率熔解曲线分析（HRM）用于确定 pfcrt 单倍型和 pfmdr1 SNPs 的流行率。此外，使用实时 PCR 确定 pfmdr1 基因拷贝数（CNV）。P 值≤0.05 被认为具有统计学意义。

结果

在 225 个样本中，95.5%、94.4%、86.7%、91.1%和 94.2%的样本成功地进行了 HRM 基因分型，分别用于 pfcrt 单倍型、pfmdr1-86、pfmdr1-184、pfmdr1-1042 和 pfmdr1-1246。在 Assosa 和 Gida Ayana 两个地点采集的样本中，分别有 33.5%（52/155）和 80%（48/60）的疟原虫携带突变的 pfcrt 单倍型。与 Assosa 地区相比，Gida Ayana 地区的氯喹耐药性疟原虫 pfcrt 单倍型更为常见（COR=8.4，P=0.00）。Pfmdr1-N86Y 野生型和 184F 突变分别在 79.8%（166/208）和 73.4%（146/199）的样本中发现。pfmdr1-1042 位点未发现单个突变；然而，西埃塞俄比亚的 89.6%（190/212）的寄生虫携带野生型 D1246Y 变体。在密码子 N86Y-Y184F-D1246Y 处鉴定出 8 种 pfmdr1 单倍型，优势单倍型为 NFD 61%（122/200）。两个研究地点的 pfmdr1 SNPs、单倍型和 CNV 分布无差异（P＞0.05）。