Atlanta Research and Education Foundation, Atlanta, GA, USA.
Malaria Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA.
Malar J. 2018 Feb 20;17(1):84. doi: 10.1186/s12936-018-2233-5.
Artemisinin-based combination therapy is the first-line anti-malarial treatment for uncomplicated Plasmodium falciparum infection in Angola. To date, the prevalence of polymorphisms in the pfk13 gene, associated with artemisinin resistance, and pfmdr1, associated with lumefantrine resistance, have not been systematically studied in Angola.
DNA was isolated from pretreatment and late treatment failure dried blood spots collected during the 2015 round of therapeutic efficacy studies in Benguela, Lunda Sul, and Zaire Provinces in Angola. The pfk13 propeller domain and pfmdr1 gene were sequenced and analysed for polymorphisms. Pfmdr1 copy number variation was assessed using a real-time PCR method. The association between pfmdr1 and pfk13 mutations and treatment failure was investigated.
The majority of pretreatment (99%, 466/469) and all late treatment failure (100%, 50/50) samples were wild type for pfk13. Three of the pretreatment samples (1%) carried the A578S mutation commonly observed in Africa and not associated with artemisinin resistance. All 543 pretreatment and day of late treatment failure samples successfully analysed for pfmdr1 copy number variation carried one copy of pfmdr1. The NYD haplotype was the predominant pfmdr1 haplotype, present in 63% (308/491) of pretreatment samples, followed by NFD, which was present in 32% (157/491) of pretreatment samples. The pfmdr1 N86 allele was overrepresented in day of late treatment failure samples from participants receiving artemether-lumefantrine (p value 0.03).
The pretreatment parasites in patients participating in therapeutic efficacy studies in 2015 in Angola's three sentinel sites showed genetic evidence of susceptibility to artemisinins, consistent with clinical outcome data showing greater than 99% day 3 clearance rates. The lack of increased pfmdr1 copy number is consistent with previous reports from sub-Saharan Africa. Although pfmdr1 NYD and NFD haplotypes were overrepresented in artemether-lumefantrine late treatment failure samples, their role as markers of resistance was unclear given that these haplotypes were also present in the majority of successfully treated patients in the artemether-lumefantrine treatment arms.
在安哥拉，青蒿素为基础的联合疗法是治疗无并发症恶性疟原虫感染的一线抗疟药物。迄今为止，与青蒿素耐药相关的 pfk13 基因和与咯萘啶耐药相关的 pfmdr1 基因的多态性尚未在安哥拉进行系统研究。
从 2015 年在安哥拉本格拉、南隆达和扎伊尔省进行的疗效研究中采集的治疗前和晚期治疗失败的干血斑中提取 DNA。对 pfk13 推进器结构域和 pfmdr1 基因进行测序和分析，以确定多态性。采用实时 PCR 方法评估 pfmdr1 拷贝数变异。研究了 pfmdr1 和 pfk13 突变与治疗失败之间的关系。
大多数治疗前（99%，466/469）和所有晚期治疗失败（100%，50/50）样本 pfk13 均为野生型。有 3 个治疗前样本（1%）携带常见于非洲且与青蒿素耐药无关的 A578S 突变。所有 543 个治疗前和晚期治疗失败日样本均成功分析了 pfmdr1 拷贝数变异，携带一个 pfmdr1 拷贝。NYD 单倍型是 pfmdr1 单倍型的主要类型，存在于 63%（308/491）的治疗前样本中，其次是 NFD，存在于 32%（157/491）的治疗前样本中。在接受青蒿琥酯-咯萘啶治疗的晚期治疗失败日样本中，pfmdr1 N86 等位基因的比例过高（p 值 0.03）。
2015 年在安哥拉三个哨点参加疗效研究的患者的治疗前寄生虫对青蒿素具有遗传证据表明敏感性，与临床结果数据显示 99%以上的第 3 天清除率一致。pfmdr1 拷贝数增加的缺乏与来自撒哈拉以南非洲的先前报告一致。尽管 pfmdr1 NYD 和 NFD 单倍型在青蒿琥酯-咯萘啶治疗失败的晚期样本中占优势，但由于这些单倍型也存在于青蒿琥酯-咯萘啶治疗组中大多数成功治疗的患者中，因此它们作为耐药标志物的作用尚不清楚。
