Isolation and identification of Sheep-origin Proteus mirabilis and evaluation of immunization effect of inactivated vaccine
10.16303/j.cnki.1005-4545.2025.09.16
- VernacularTitle:羊源奇异变形杆菌分离鉴定及灭活疫苗免疫效果评价
- Author:
Wei FAN
1
;
Yilu ZHAI
;
Wei WANG
;
Xinyu ZHANG
;
Jiaqi FU
;
Dazhuo ZHAO
;
Fuliang SUN
Author Information
1. 延边大学农学院,吉林延吉 133002
- Publication Type:Journal Article
- Keywords:
sheep;
Proteus mirabilis;
inactivated vaccine;
immunoprotection
- From:
Chinese Journal of Veterinary Science
2025;45(9):1944-1951
- CountryChina
- Language:Chinese
-
Abstract:
To investigate the pathogenicity of Sheep-origin Proteus mirabilis and the immunity effect of its inactivated vaccine.In this study,autopsy were performed on sick and dead sheep with severe diarrhea,collected liver,spleen and other diseased organs.And identified the isolated strains by morphology,Gram staining microscopy,biochemical test,molecular biology and 16S rRNA se-quencing;Drug resistance and pathogenicity were studied by drug sensitivity test,pathogenicity test in mouse and pathological histological observation;The isolated strains were inactivated by formaldehyde and mixed with alum adjuvant containing aluminum hydroxide to prepare the inacti-vated vaccine;mice were immunized after safety testing to test antibodies,cytokines and evaluate the immunological effects.Results showed that the isolate was Gram-negative short bacillus with blunt rounded ends after purification staining.Combined with biochemical tests,PCR amplified fragments and 16S rRNA sequencing results showed that the strain was Proteus mirabilis;The re-sults of drug sensitivity test showed that the isolate was highly sensitive to four antibiotics,including amikacin and piperacillin(S),the rest of the strain was moderately or poorly sensitive,or even resistant;The isolate was highly sensitive to the four antibiotics,such as amikacin and pip-eracillin(S).The lethal concentration of the isolated strain was 1.6 × 105 CFU/mL and it could cause different degrees of congestion and bruising and inflammatory cell infiltration in the liver,spleen and other major organs;The formaldehyde inactivated vaccine did not cause adverse reac-tions in mice,and the serum levels of antibodies to IgG,IgG1 and IgG2a,and the levels of antibod-ies to IL-4 and IFN-γ were higher than that of the PBS group,and the vaccine immunoprotection rate was 90％in the attacking bacterial test.In the present experiment,Proteus mirabilis was suc-cessfully isolated from the organs of sick and dead sheep.The inactivated vaccine prepared by form-aldehyde inactivation method can mediate humoral immunity to play a preventive role against the infection of S.chimaera,which can provide a new method for the prevention of bacterial diseases in sheep breeding.
