中国寄生虫学与寄生虫病杂志

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2015年河南省输入性恶性疟原虫Pfcrt基因的多态性分析

周瑞敏1,王轶楠2,钱丹1,李素华1,刘颖1,杨成运1,赵玉玲1,许汴利1,张红卫1*   

  1. 1 河南省疾病预防控制中心,郑州450016;2漯河医学高等专科学校,漯河462000
  • 出版日期:2016-10-30 发布日期:2016-11-09

Analysis of Pfcrt Gene Polymorphism in Imported Falciparum Malaria Cases in Henan Province in 2015

ZHOU Rui-min1,WANG Yi-nan2,QIAN Dan1,LI Su-hua1,LIU Ying1,YANG Cheng-yun1,ZHAO Yu-ling1,XU Bian-li1,ZHANG Hong-wei1*   

  1. 1 Henan Centre for Disease Control and Prevention, Zhengzhou 450016, China;2 Luohe Medical College, Luohe 462000, China
  • Online:2016-10-30 Published:2016-11-09

摘要: 目的 对河南省2015年输入性恶性疟患者血样的恶性疟原虫氯喹抗性转运蛋白(Plasmodium falciparum chloroquine resistant transporter,Pfcrt)基因进行检测,分析其基因多态性。 方法 采集河南省2015年132例输入性恶性疟患者的血样,并收集患者相关信息。提取患者血样中恶性疟原虫基因组DNA,采用已有的Pfcrt基因序列引物,进行巢式PCR扩增,扩增产物经ApolⅠ酶切和测序,分析输入性恶性疟原虫Pfcrt基因多态性及其分布情况。 结果 132例输入性恶性疟患者以男性青壮年为主,均为自非洲19个国家的劳务返乡人员,其中以西非居多,占38.6%(51/132),其他依次为中非(占26.5%,35/132)、南非(25.0%,33/132),东非(占8.3%,11/132)和北非(占1.5%,2/132)。患者血样DNA经巢式PCR扩增,均获得约145 bp的特异性片段。扩增产物经ApolⅠ酶切,66.7%(88/132)患者血样的扩增产物被完全酶切,出现114 bp和31 bp两个片段;32.6%(43/132)不能被酶切,仅出现145 bp单个片段;0.8%(1/132)则酶切不完全,产生145 bp、114 bp和31 bp等3个片段。测序结果显示,132份患者血样的扩增产物经测序获得的Pfcrt基因序列,与氯喹敏感株3D7序列比对,其中43份血样(占32.6%)的Pfcrt基因序列编码的74、75和76位氨基酸碱基由ATG、AAT和AAA突变为ATT、GAA和ACA,即M74I、N75E和K76T,为突变型(CVIET);1份血样(占0.8%)的Pfcrt基因序列编码的74~76位氨基酸碱基则突变为ATG/T、A/GAA/T和AA/CA,为混合型(CVM/I、N/E/D/K、T/K);88份血样(占66.7%)的Pfcrt基因序列未发生改变,为野生型(CVMNK)。自西非输入的恶性疟病例突变型所占比例最多,为41.2%(21/51),其他依次为东非(4/11)、南非(30.3%,10/33)和中非(22.9%,8/27),三者比较差异无统计学意义(χ2=4.07,P>0.05)。自北非输入的2例均为野生型;1例基因混合型自西非输入。 结论 2015年河南省自非洲19个国家输入的恶性疟原虫Pfcrt基因存在3种类型,野生型(CVMNK)、突变型(CVIET)和混合型(CVM/I、N/E/D/K、T/K),野生型(CVMNK)所占比例最高(66.7%);自西非地区输入的突变型(CVIET)所占比例最多(41.2%)。

关键词: 输入性疟疾, 恶性疟原虫, 氯喹抗性转运蛋白基因, 多态性

Abstract: Objective To analyze Plasmodium falciparum chloroquine resistant transporter(Pfcrt) gene polymorphism in imported falciparum malaria cases in Henan Province in 2015. Methods Blood samples were collected from 132 cases of imported falciparum malaria in Henan Province in 2015. DNA was extracted from the samples, and the Pfcrt was amplified by nested PCR using specific primers. The PCR products were digested by restriction endonuclease enzyme ApolⅠ and sequenced. Pfcrt gene polymorphism and distribution were analyzed. Results Most of the 132 cases of imported malaria were young male adults returning from the Africa, with the highest percentage in those from West Africa(38.6%, 51/132), then Central Africa(26.5%, 35/132), South Africa(25.0%, 33/132), East Africa(8.3%, 11/132), and North Africa(1.5%, 2/132). The nested PCR yielded a 145-bp product for each sample, and 66.7%(88/132) of the products were completely digested by ApolⅠ, resulting in two fragments of 114 bp and 31 bp; 32.6%(43/132) could not been digested and only a single fragment of 145 bp was shown; and 0.8%(1/132) were incompletely digested, yielding three fragments of 145 bp, 114 bp and 31 bp. By blasting against chloroquine sensitive strain 3D7, we found mutations of Pfcrt at sites correspondig to residues 74, 75 and 76 from ATG, AAT and AAA to ATT, GAA and ACA (i.e. M74I, N75E and K76T) in 43 of the 132 blood samples, and mixed type mutations into ATG/T, A/GAA/T and AA/CA at sites correspondig to residues 74, 75 and 76(CVM/I, N/E/D/K, T/K) in one blood sample. The other 88 blood samples showed a wild type with no mutation(CVMNK). Mutations occurred mainly in cases from West Africa(41.2%, 21/51), then East Africa(36.4%, 4/11), South Africa(30.3%, 10/33), and Central Africa(22.9%, 8/27)(χ2=4.07, P>0.05). The 2 cases from the North Africa both had wild type Pfcrt; the one with mixed type mutation was from West Africa. Conclusion Three haplotypes of Pfcrt have been found, including wild type(CVMNK), mutation type(CVIET) and mixed type(CVM/I, N/E/D/K, K/T) in the imported malaria cases. The wild type occupies the highest proportion (66.7%), while the mutation type possesses a high proportion of 41.2% in cases from West Africa.

Key words: Imported malaria, Plasmodium falciparum, Chloroquine resistant transporter, Polymorphism