DataSheet_1_In vitro susceptibility profile of Plasmodium falciparum clinical isolates from Ghana to antimalarial drugs and polymorphisms in resistance markers.pdf

Drug resistance in Plasmodium falciparum compromises the effectiveness of antimalarial therapy. This study aimed to evaluate the extent of drug resistance in parasites obtained from international travelers returning from Ghana to guide the management of malaria cases. Eighty-two clinical parasite isolates were obtained from patients returning from Ghana in 2016–2018, of which 29 were adapted to continuous in vitro culture. Their geometric mean IC50 values to a panel of 11 antimalarial drugs, assessed using the standard SYBR Green-I drug sensitivity assay, were 2.1, 3.8, 1.0, 2.7, 17.2, 4.6, 8.3, 8.3, 19.6, 55.1, and 11,555 nM for artemether, artesunate, dihydroartemisinin, lumefantrine, mefloquine, piperaquine, naphthoquine, pyronaridine, chloroquine, quinine, and pyrimethamine, respectively. Except for chloroquine and pyrimethamine, the IC50 values for other tested drugs were below the resistance threshold. The mean ring-stage survival assay value was 0.8%, with four isolates exceeding 1%. The mean piperaquine survival assay value was 2.1%, all below 10%. Mutations associated with chloroquine resistance (pfcrt K76T and pfmdr1 N86Y) were scarce, consistent with the discontinuation of chloroquine a decade ago. Instead, the pfmdr1 86N-184F-1246D haplotype was predominant, suggesting selection by the extensive use of artemether-lumefantrine. No mutations in the pfk13 propeller domain were detected. The pfdhfr/pfdhps quadruple mutant IRNGK associated with resistance to sulfadoxine-pyrimethamine reached an 82% prevalence. In addition, five isolates had pfgch1 gene amplification but, intriguingly, increased susceptibilities to pyrimethamine. This study showed that parasites originating from Ghana were susceptible to artemisinins and the partner drugs of artemisinin-based combination therapies. Genotyping drug resistance genes identified the signature of selection by artemether-lumefantrine. Parasites showed substantial levels of resistance to the antifolate drugs. Continuous resistance surveillance is necessary to guide timely changes in drug policy.

恶性疟原虫（Plasmodium falciparum）的耐药性会削弱抗疟治疗的有效性。本研究旨在评估从加纳归国的国际旅行者体内分离的疟原虫的耐药程度，以指导疟疾病例的临床诊疗。本研究于2016至2018年间，从加纳归国的患者体内分离得到82株临床疟原虫分离株，其中29株可适应持续体外培养体系。采用标准SYBR Green-I药物敏感性试验检测后，11种抗疟药物的几何平均半数抑制浓度（IC50）依次为：蒿甲醚2.1 nM、青蒿琥酯3.8 nM、双氢青蒿素1.0 nM、苯芴醇2.7 nM、甲氟喹17.2 nM、哌喹4.6 nM、萘喹8.3 nM、咯萘啶8.3 nM、氯喹19.6 nM、奎宁55.1 nM、乙胺嘧啶11555 nM。除氯喹与乙胺嘧啶外，其余受试药物的IC50值均低于耐药阈值。环状体存活试验的平均检测值为0.8%，其中4株分离株的数值超过1%。哌喹存活试验的平均检测值为2.1%，所有分离株均低于10%。与氯喹耐药相关的突变（pfcrt K76T与pfmdr1 N86Y）较为罕见，这与十年前氯喹的停用政策相一致。与之相反，pfmdr1 86N-184F-1246D单倍型为优势单倍型，提示其受到了蒿甲醚-苯芴醇广泛使用的选择压力。未检测到pfk13基因螺旋桨结构域的突变。与磺胺多辛-乙胺嘧啶耐药相关的pfdhfr/pfdhps四重突变体IRNGK的检出率达到82%。此外，有5株分离株存在pfgch1基因扩增，但令人意外的是，这些分离株对乙胺嘧啶的敏感性反而升高。本研究表明，源自加纳的疟原虫对青蒿素类药物以及青蒿素联合疗法的配伍药物均敏感。耐药基因分型结果揭示了蒿甲醚-苯芴醇的药物选择压力特征。疟原虫对抗叶酸类药物表现出显著的耐药水平。持续开展耐药监测对于及时调整抗疟药物政策具有重要指导意义。