浙江省天台县2011－2018年汉坦病毒基因型别和进化变异研究

目的 研究2011－2018年肾综合征出血热（HFRS）国家监测点浙江省天台县汉坦病毒（HV）的基因型别和进化变异情况，了解天台县HV分子流行病学特点。方法 将天台县2011－2018年HV抗原阳性的鼠肺标本超声后提取核酸，利用HV型特异性引物，应用巢式PCR对部分M片段进行扩增分型和序列测定，将天台县2011－2018年的HV序列与国内外其他已知的HV序列进行比较，以明确该地区的基因型别，分析病毒的进化变异情况。结果 HV抗原阳性的67份鼠肺标本经型特异性引物巢式PCR扩增后31份标本为阳性，其中30份为汉滩病毒（HTNV）、1份为汉城病毒（SEOV），31份PCR阳性鼠肺均来自黑线姬鼠。31份巢式PCR阳性产物的部分M片段核苷酸序列有30株分布在HTNV单元群，1株分布在SEOV单元群。HTNV单元群中的天台T2018-130株与天台其余29株及国内外其他株同源性为84.8%～87.9%，差异较大，天台其余29株亲缘关系较近； SEOV发生群中的T2016-31株来自黑线姬鼠的鼠肺标本，与SEOV天台以往分离株ZT71株、ZT10株和浙江温州分离株Z37株在系统发生树上分布于同一或临近分支。结论 浙江省天台县HV流行的主要型别HTNV基因表现出明显的地理聚集现象，但也存在着基因差异较大的变异株T2018-130株；同时从病毒基因序列分析证实SEOV T2016-31株存在于黑线姬鼠中，可能意味着在SEOV进化过程中病毒在宿主间发生了“溢出”现象。     

Visual detection technique for efficient screening and isolation of <Emphasis Type="Italic">Salmonella</Emphasis> based on a novel enrichment assay using chromatography membrane

To detect Salmonella more efficiently and isolate strains more easily, a novel and simple detection method that uses an enrichment assay and two chromogenic reactions on a chromatography membrane was developed. Grade 3 chromatography paper is used as functionalized solid phase support (SPS), which contains specially optimized medium. One reaction for screening is based on the sulfate-reducing capacity of Salmonella. Hydrogen sulfide (H₂S) generated by Salmonella reacts with ammonium ferric citrate to produce black colored ferrous sulfide. Another reaction is based on Salmonella C8 esterase that is unique for Enterobacteriaceae except Serratia and interacts with 4-methylumbelliferyl caprylate (MUCAP) to produce fluorescent umbelliferone, which is visible under ultraviolet light. A very low detection limit (10¹ CFU ml^?1) for Salmonella was achieved on the background of 10⁵ CFU ml^?1 Escherichia coli. More importantly, testing with more than 1,000 anal samples indicated that our method has a high positive detection rate and is relatively low cost, compared with the traditional culture-based method. It took only 1 day for the preliminary screening and 2 days to efficiently isolate the Salmonella cells, indicating that the new assay is specific, rapid, and simple for Salmonella detection. In contrast to the traditional culture-based method, this method can be easily used to screen and isolate targeted strains with the naked eye. The results of quantitative and comparative experiments showed that the visual detection technique is an efficient alternative method for the screening of Salmonella spp. in many applications of large-sized samples related to public health surveillance.