马鞍山市志贺菌福氏4c亚型毒力基因检测及分子分型研究

目的了解马鞍山市志贺菌福氏4 c(ShigellaF4c)分离株的毒力基因的流行模式及分子分型的特点,掌握Shi-gellaF4c在该市的流行状况。方法使用常规法进行菌株分离培养、使用全自动微生物鉴定系统进行生化鉴定,鉴定为志贺菌的阳性菌株使用PCR检测ShigellaF4c的ipa H、ial、set、sen四种毒力基因及应用PFGE进行分子分型。结果 ipa H、ial、set、sen四种毒力基因在76株ShigellaF4c的携带率分别为100%、97.4%、96.1%、90.8%,其中67株ShigellaF4c四种毒力基因全为阳性,占88.2%;本地区ShigellaF4c携带毒力基因模式分成五大类型,Ⅰ型是主要毒力基因模式。PFGE电泳条带图谱显示,ShigellaF4c中100%相同的菌株数较少;100%相同的都为同一年代,91%相同的菌株出现跨年度;不同年代分离株无完全相同基因型,地域方面没有明显联系。结论马鞍山地区S.F4c分离株携带ipa H、ial、set、sen四种毒力基因普遍存在,毒力强是本地区ShigellaF4c主要特征之一;ShigellaF4c在本地区无显著的流行迹象,属于散在发病。

Genotype identification and virulence gene analysis of Shigella flexneri4c subtype in Ma'anshan City

The objective of the present study was to understand the epidemic type of virulence gene and the characteristics of molecular typing in Shigella flexneri4c（F4c） isolates in Ma＇anshan city.These strains were isolated and cultured by conventional method and the biochemical characteristics were identified by AMS.PCR was used to detect ipaH,ial,set and sen virulence genes in identified Shigellastrains and pulse-field gel electrophoresis（PFGE） was used in molecular identification.Results demonstrated that the distribution rates of ipaH,ial,set and sen virulence genes among these 76 strains was 100%,97.4%,96.1% and 90.8% respectively and the four virulence genes reacted positively in 67 ShigellaF4c strains.There were five types of virulence gene-carried pattern in this area and was dominated by TypeⅠ.Results of PFGE showed that 100% identical ShigellaF4c strains was minority.The 100% identical strains were appeared in the same generation,while the 91% identical strains were appeared cross generations.Isolates from differential generations did not have the same gene type completely and have no regional relation.It＇s indicated that these ShigellaF4c isolates in Ma＇anshan City carried four virulence genes as ipaH,ial,set and senamong them generally with a main characteristic of strong virulence.Meanwhile,ShigellaF4c is defined as sporadic disease as there is no epidemic sign in this area.