青海牦牛源沙门氏菌的分离鉴定、耐药表型及毒力基因分析

Isolation and identification,drug resistance phenotype and virulence gene analysis of Qinghai yak-derived Salmonella

为了调查青海省玉树藏族自治州部分地区散养牦牛腹泻粪便中沙门氏菌的流行情况、耐药表型及毒力基因分布情况,试验采用病原菌分离、生化鉴定、形态学观察、PCR扩增、K-B法及玻片凝集等方法对腹泻粪便样品进行沙门氏菌的筛选,进而对分离株进行14种毒力基因的筛选、四大类抗生素的药物敏感性检测和血清型检测。结果表明:从184份牦牛腹泻粪便样品中共分离出32株沙门氏菌,分离率为17.39%;分离株共包括3种血清型,以鼠伤寒沙门氏菌为优势血清型,分离率为71.875%;沙门氏菌分离株对新霉素、链霉素、氨苄西林、红霉素及青霉素的耐药率为71.88%~100%;分离株对sseL、orfL、rhuM、avrA、sodC1、lpfC 6种毒力基因的携带率为100%,对sopB、sopE、pipD、ttrB 4种毒力基因的携带率为93.75%,对orgA、mgtc毒力基因的携带率为90.62%,所有菌株均未能检出pefA和spvC毒力基因。说明导致青海省玉树藏族自治州部分地区牦牛腹泻的沙门氏菌血清型大部分为携带多种毒力基因的鼠伤寒沙门氏菌分离株,且表现出不同程度的耐药情况。

In order to initially grasp the prevalence of Mycoplasma bovis(M.bovis)disease in Ningxia region,the experiment was conducted by using ELISA method to detect M.bovis serum antibodies in bovine serum samples collected from 22 counties/districts in 5 cities in Ningxia region from 20202021 and to analyze the results of serological investigation in different years,cities and counties/districts.The results showed that M.bovis antibody detection was all positive in five cities in Ningxia region,Gouyuan City,Shizuishan City,Wuzhong City,Zhongwei City and Yinchuan City.The average M.bovis antibody positivity rates in 2020 and 2021 were(29.39±15.07)%,(37.58±19.52)%,respectively.Highly significant difference was in positive rates of serum M.bouis antibody in 2021 compared to 2020(P<0.01).Comparing between different cities,the two-year average M.bovis antibody positive rates were(22.00±8.78)%,(35.56±14.09)%,(31.11±10.47)%,(50.00±25.91)%,and(29.44±9.19)%in Guyuan City,Zhongwei City,Shizuishan City,Wuzhong City,and Yinchuan City respectively;the highest average M.bovis antibody positive rate was in Wuzhong City,and the lowest in Guyuan City.The positive rates of M.bovis antibody in Xiji County and Tongxin County did not change in two years when compared among different counties/districts.The positive rates of M.bovis antibody in Yuanzhou District and Pingluo County in 2021 decreased compared to the positive rates in 2020.The positiverates of M.bovis antibody in the other18 counties and districts in 2021 showed an increasing trend compared with 2020,witha significant difference(P<0.05)between the two years of comparison in Litong and Hongsibao Districts.The results indicated that the positive rates of serum M.bovis antibody had an increasing trend in Ningxia region over a 2-year period.