Interpretation criteria for standardized Western blot for the predominant species of Borrelia burgdorferi sensu lato in China

Objective Western blotting （WB;immunoblotting） is a widely used tool for the serodiagnosis of Lyme borreliosis （LB）,but so far,no generally accepted criteria for its performance and interpretation have been established in China.The present study was designed to determine the criteria for standardized Western blot for the predominant species of Borrelia burgdorferi sensu lato in China,in which WB was produced with strain PD91 as the representative strain attributed to predominant genospecies Borrelia garinii of Borrelia burgdorferi sensu lato.Methods Approximately 13 bands between 14 and 100 kD were differentiated for strain PD91 by using Gel-Pro analysis software.In a study with 631 serum samples （taken from 127 patients with Lyme borreliosis and 504 controls）,all observed bands were documented.To establish criteria for a positive WB result for strain PD91,receiver operating characteristic （ROC） curves were used.Results The following interpretation criteria were recommended：for IgG,at least one band of P83/100,P58,P39,P30,OspC,P17,P66,and OspA;for IgM,at least one band of P83/100,P58,OspA,P30,OspC,P17 or P41.In addition,syphilis,leptospirosis and other related diseases should be excluded when the positive band is P41 in IgM.For IgG criteria,the sensitivity is 73.2%,the specificity is 99.4% and Youden index is 0.726;for IgM criteria,the sensitivity is 50.6%,the specificity is 93.1% and Youden index is 0.437.Conclusion Standardization of WB assays is necessary for comparison of results from different laboratories.Moreover,the criteria of other genospecies of Borrelia burgdorferi sensu lato should be determined in the future to complete the criteria of WB for the diagnosis of the Lyme disease in China.     

北京地区实验动物绿脓杆菌分离株MLVA分型

目的 通过多位点可变数目串联重复序列分析(multiple-locus variable-number tandem-repeat analysis,MLVA)分型方法,研究北京地区实验动物绿脓杆菌分离株基因型和分布情况.方法 选择13个可变数目重复序列(variable-number tandem-repeat,VNTR)位点,对实验动物及设施中检测出的141株绿脓杆菌的基因组DNA进行重复序列扩增,所得指纹图谱使用BioNumerics软件进行聚类分析,绘制系统发育树和最小生成树(minimum spanning tree,MST).结果 所采用的13个VNTR位点能够对全部分离株进行有效分型.141株绿脓杆菌主要被分为了3个基因群,56个基因型.各群所占比例分别为A群82.3％,B群占12.8％,C群占5.0％,辛普森多样性指数为0.763.同一区域内相邻实验动物单位的绿脓杆菌分离株同源关系较远.结论 MLVA方法对绿脓杆菌具有很好的分型能力,能够有效的追踪绿脓杆菌的来源.北京地区实验动物中绿脓杆菌分离株基因型多态性丰富,但无地域性同源关系.     

莱姆病螺旋体中国分离株外膜蛋白C基因的克隆与序列分析

目的了解引起我国莱姆病的伯氏疏螺旋体外膜蛋白Ｃ（ＯｓｐＣ）基因变异情况。方法应用聚合酶链反应从２株莱姆病螺旋体中国分离株ＢＴ０１和ＢＪ－９０１１全基因组ＤＮＡ中将ＯｓｐＣ基因调出,并插入质粒ｐＧＥＭ－３ＺＦ（＋）中,构建重组质粒ｐＧＥＭ－３ＺＦ（＋）－ＯｓｐＣ,经Ｓａｎｇｅｒ双脱氧末端终止法测序,并将之与国外其它分离株进行同源性比较。结果除信号肽序列外,２株莱姆病螺旋体分离株ＢＴ０１和ＢＪ－９０１１的ＯｓｐＣ基因依次为５７９ｂｐ和５７６ｂｐ,分别编码１９３和１９２氨基酸,两者核苷酸和氨基酸序列的同源性分别为８６％和８３％,与国外分离株（ＰＢｉ、ＰＫｏ及Ｂ３１）的同源性均较高,其中ＢＪ－９０１１株与国际标准株Ｂ３１株之间核苷酸及氨基酸同源性达９９％。结论伯氏疏螺旋体Ｏｓ－ｐＣ基因在国内２个分离株之间存在一定差异,其与国外分离株之间也存在一定差异