大湄公河次区域抗疟药物耐药性的分子流行病学：一项观察性研究。

BACKGROUND: The Greater Mekong subregion is a recurrent source of antimalarial drug resistance in Plasmodium falciparum malaria. This study aimed to characterise the extent and spread of resistance across this entire region between 2007 and 2018. METHODS: P falciparum isolates from Myanmar, Thailand, Laos, and Cambodia were obtained from clinical trials and epidemiological studies done between Jan 1, 2007, and Dec 31, 2018, and were genotyped for molecular markers (pfkelch, pfcrt, pfplasmepsin2, and pfmdr1) of antimalarial drug resistance. Genetic relatedness was assessed using microsatellite and single nucleotide polymorphism typing of flanking sequences around target genes. FINDINGS: 10 632 isolates were genotyped. A single long pfkelch Cys580Tyr haplotype (from -50 kb to +31·5 kb) conferring artemisinin resistance (PfPailin) now dominates across the eastern Greater Mekong subregion. Piperaquine resistance associated with pfplasmepsin2 gene amplification and mutations in pfcrt downstream of the Lys76Thr chloroquine resistance locus has also developed. On the Thailand-Myanmar border a different pfkelch Cys580Tyr lineage rose to high frequencies before it was eliminated. Elsewhere in Myanmar the Cys580Tyr allele remains widespread at low allele frequencies. Meanwhile a single artemisinin-resistant pfkelch Phe446Ile haplotype has spread across Myanmar. Despite intense use of dihydroartemisinin-piperaquine in Kayin state, eastern Myanmar, both in treatment and mass drug administrations, no selection of piperaquine resistance markers was observed. pfmdr1 amplification, a marker of resistance to mefloquine, remains at low prevalence across the entire region. INTERPRETATION: Artemisinin resistance in P falciparum is now prevalent across the Greater Mekong subregion. In the eastern Greater Mekong subregion a multidrug resistant P falciparum lineage (PfPailin) dominates. In Myanmar a long pfkelch Phe446Ile haplotype has spread widely but, by contrast with the eastern Greater Mekong subregion, there is no indication of artemisinin combination therapy (ACT) partner drug resistance from genotyping known markers, and no evidence of spread of ACT resistant P falciparum from the east to the west. There is still a window of opportunity to prevent global spread of ACT resistance. FUNDING: Thailand Science Research and Innovation, Initiative 5%, Expertise France, Wellcome Trust.

背景：大湄公河次区域是恶性疟原虫对青蒿素类药物耐药性的反复出现的来源。本研究旨在描述 2007 年至 2018 年期间整个区域耐药性的程度和传播范围。

方法：从 2007 年 1 月 1 日至 2018 年 12 月 31 日期间进行的临床试验和流行病学研究中获得来自缅甸、泰国、老挝和柬埔寨的恶性疟原虫分离株，并对其进行抗疟药物耐药性的分子标记（pfkelch、pfcrt、pfplasmepsin2 和 pfmdr1）基因分型。使用侧翼目标基因序列的微卫星和单核苷酸多态性分型评估遗传相关性。

结果：对 10632 个分离株进行了基因分型。一种单一的长 pfkelch Cys580Tyr 单倍型（从-50 kb 到+31.5 kb），赋予对青蒿素的耐药性（PfPailin），现在在大湄公河次区域东部占据主导地位。与 pfplasmepsin2 基因扩增和位于 Lys76Thr 氯喹耐药位点下游的 pfcrt 突变相关的哌喹耐药性也已出现。在泰国-缅甸边境，另一种 pfkelch Cys580Tyr 谱系在被消除之前曾高频出现。在缅甸其他地方，Cys580Tyr 等位基因仍然广泛存在，但等位基因频率较低。与此同时，一种单一的对青蒿素耐药的 pfkelch Phe446Ile 单倍型已在整个缅甸传播。尽管在缅甸东部的克耶邦（Kayin state）大量使用二氢青蒿素-哌喹进行治疗和大规模药物管理，但在观察到对哌喹耐药性标记物的选择。pfmdr1 扩增，一种对甲氟喹耐药的标志物，在整个地区的流行率仍然很低。

解释：恶性疟原虫对青蒿素的耐药性现已在大湄公河次区域普遍存在。在大湄公河次区域东部，一种多药耐药的恶性疟原虫谱系（PfPailin）占据主导地位。在缅甸，一种长的 pfkelch Phe446Ile 单倍型已广泛传播，但与大湄公河次区域东部不同的是，从已知标记物的基因分型来看，没有表明对青蒿素联合疗法（ACT）联合用药的耐药性，也没有证据表明来自东部的对 ACT 耐药的恶性疟原虫传播到西部。现在仍有机会防止 ACT 耐药性在全球范围内传播。

资金：泰国科学研究和创新、倡议 5%、法国专家、惠康信托基金会。