广西伯氏疏螺旋体外膜蛋白A基因型分析

Genotyping of the OSPA gene of Borrelia burgdorferi in isolates from Guangxi

目的了解广西伯氏疏螺旋体外膜蛋白A(OspA)基因型别及变异情况。方法应用PCR技术从6株伯氏疏螺旋体广西分离株QLT1,QLM13,QLM4,GXSH7,GXLR8及QXM13全基因组DNA中扩增出OspA基因,对所检测到的阳性结果进行序列测定,并与广西以及国外其它分离株进行同源性比较。结果6株伯氏疏螺旋体广西分离株OspA基因扩增片段长度均为774bp,编码258个氨基酸。其核苷酸同源性为97.67%~99.99%,氨基酸同源性>98%,其中QLT1与QLM4之间的核苷酸同源性为99.99%,且与之前分离到的4株广西伯氏疏螺旋体及国外分离株(B.sp10MT)的OSPA基因同源性均较高。结论伯氏疏螺旋体OSPA基因在广西分离株之间差异较小,与属于Borrelia valaisiana基因型的国内外分离株同源性较好。

Objective To investigate the genotype and variation of the outer membrane protein A(OspA)gene of Borrelia burgdorferi in isolates from Guangxi.Methods PCR was used to amplify the OSPA gene from the genomic DNA of QLT1,QLM13,QLM4,GXSH7,GXLR8,and QXM13 isolates.Positive samples were sequenced and then subjected to phylogenetic analysis for comparison to Guangxi isolates and foreign isolates.Results Excluding the signal peptide,the OSPA genes of all six isolates were 774 bp length and consisted of 258 amino acids.The nucleotide sequence similarity among the six strains was 97.67-99.99%and the amino acid sequence similarity was greater than 98%.There was up to99.99%nucleotide sequence similarity between QLT1 and QLM4.The OspA genes of the 10 Guangxi strains of B.berghei are highly similar,with a nucleotide similarity>97%.Compared to 12 isolates of B.burgdorferi with different genotypes,Guangxi isolates are highly similar to B.valaisianaspirochetes(B.sp10 MT).Conclusion The OspA gene is markedly similar among Guangxi isolates.There is a high level of similarity between Guangxi isolates and B.valaisianaspirochetes.