贵州省B3基因型麻疹病毒分子特征

Molecular characterization of measles virus of genotype B3 isolated in Guizhou province

目的分析贵州省2014年首次发现B3基因型麻疹病毒分子特征。方法采集咽拭子经实时荧光定量逆转录-聚合酶链反应（real-time RT-PCR）筛查麻疹病毒核酸。用逆转录-聚合酶链反应（RT-PCR）扩增麻疹病毒核酸筛查阳性咽拭子,对麻疹病毒N基因羧基末端634个核苷酸片段进行扩增,对扩增产物进行序列测定和分析,构建基因亲缘性关系树。结果 Guizhou14-06（MVs/Guizhou.CHN/11.14/01）在亲缘关系上与WHO B3基因型参考株MVi/Ibadan.NGA/0.97/1（AJ232203）同属一个分支,与MVi/Ibadan.NGA/0.97/1（AJ232203）的核苷酸和氨基酸差异分别为2.00%和2.67%;与中国目前的优势流行参考株MVi/Hunan.CHN/0.93/7（AF045212）的核苷酸和氨基酸差异分别为10.8%和12.0%;与其他WHO 22个基因型参考株的核苷酸和氨基酸差异分别为4.40%-11.0%和4.67%-12.0%。结论 B3基因型麻疹病毒是贵州省首次发现的新基因型麻疹病毒,丰富贵州省麻疹病毒分子流行病学基线数据,并有助于麻疹病毒的控制和消除工作。

Objective To analyze the molecular characteristics of measles virus of genotype B3 isolated firstly in Guizhou province in 2014. Methods Throat swab specimens were collected from patients with clinically diagnosed measles and tested for viral RNA using real-time reverse transcription-polymerase chain reaction（ real-time RT-PCR） after RNA extraction. Fragments of 634 nucleotides of the carboxyl end of nucleoprotein gene were amplified by using reverse transcription-polymerase chain reaction（ RT-PCR） and then the PCR products were directly sequenced and analyzed. The phylogenetic analysis was based on the 450 bp C-terminal end of the N gene sequences. Results The isolated virus strain,named MVs / Guizhou. CHN /11. 14 /01,was clustered within the same genotype group with World Health Organization（ WHO） genotype B3 reference strain,Ibadan. NGA /0. 97 /1（ AJ232203）. The nucleotide and amino acid divergence were 2. 00% and 2. 67% compared with Ibadan. NGA /0. 97 /1（ AJ232203）. Compared with WHO H1 genotype reference strain（ MVi / Hunan. CHN /0. 93 /7）,the nucleotide and amino acid divergence were 10. 8% and 12. 0%,respectively. The evolutionary distance of nucleotide and amino acid of the B3 genotype and the representative WHO 22 genotype strains were between 4. 40%- 11. 0% and 4. 67%- 12. 0%. Conclusion A newgenotype B3 measles virus was isolated in Guizhou province in 2014 and the identification of the virus strain is helpful to control and eliminate measles epidemic in Guizhou province.