山羊源志贺菌的分离鉴定及其部分生物学特性的研究

Isolation,identification and biological characteristic research of Shigella from goats

对采集自四川部分地区的226份羔羊粪便样本进行志贺菌的分离鉴定,同时对分离菌株进行血清型鉴定,并用PCR检测其携带sat、sen、set A、pic、sig A、ics P、ial、ics A、iut A、ipa H共10个毒力基因的情况;采用灌胃法检测携带毒力基因最多的4株优势血清型菌株培养物对BALB/c小鼠的致病力。经细菌分离鉴定,从226份样本中共分离到54株志贺菌;血清型鉴定结果显示,4株的血清型为福氏志贺菌1a型,11株的血清型为福氏志贺菌1b型,28株的血清型为福氏志贺菌2b型,11株的血清型为福氏志贺菌3b型。54株志贺菌均携带sat、sen、ipa H基因,而set A、pic、sig A、ics P、ial、ics A、iut A基因的阳性携带率分别为73.6%、65.2%、77.8%、82.0%、79.1%、79.1%,每个菌株携带4～10种毒力基因。携带10个毒力基因的4株福氏志贺菌2b型优势血清型菌株均在1.7×10^8CFU/m L剂量下致死全部试验小鼠,其中福氏志贺菌SWUN553对BALB/c小鼠的LD50为1.04×10^6CFU;致死小鼠的组织病理学检查显示,心、肝、脾、肺、结肠出现明显的坏死与炎性细胞浸润等病变,提示结肠为该菌入侵的最有可能部位。本研究阐明了山羊源志贺菌的部分生物学特性,为山羊志贺菌病的防控提供了科学依据。

Total 226 fecal samples collected from the goats in Sichuan Province,were used to isolate and identify Shigella.The Shigella strains isolated from goats were used to identify their serotypes and detect the carrying rates of 10 virulence genes by PCR,including sat,sen,set A,pic,sig A,ics P,ial,ics A,iut A and ipa H.According to the results of serotypes and virulence genes,the pathogenicity of 4 isolated Shigella strains to BALB/c mice was studied by oral infection.Total 54 Shigella strains were isolated from 226 fecal samples of goats and identified by specific PCR of Shigella.The serotyping results exhibited,there were 4 Shigella flexneri 1 a isolates（4/72）,11 S.flexneri 1 b isolates（11/72）,28 S.flexneri 2 b isolates（28/72）,and 11 S.flexneri 3 b isolates（11/72）.All 54 Shigella isolates carried the three virulence genes of sat,sen,ipa H.The carrying rates of other virulence genes of set A,pic,sig A,ics P,ial,ics A and iut A were 73.6%,65.2%,77.8%,82.0%,79.1% and 79.1%,respectively.Each strain carried at least 4 virulence genes,and 4 S.flexneri 2 b isolates carried 10 virulence genes,which could cause death of the no-antibiotics treated BALB/c mice at the doses of 1.7×10^8 CFU. Furthermore,the LD50 of the S.flexneri 2 b strain SWUN553 was 1.04×10^6 CFU to BALB/c mice.In histopathological examination,there appeared the necrosis,inflammatory cell infiltration and other serious damage in the heart,liver,spleen,lung and colon,which suggested that the colon might be the invasion portal of the S.flexneri 2 b strain SWUN553.This study illustrated parts of the bio-characteristics of the isolated Shigella from goats in Sichuan Province,which provided the scientific basis for the prevention and control of shigellosis in goats.