Isolation, identification and characterization of Erysipelothrix rhusiopathiae in Anhui province

Abstract:

[Objective] This study was to isolate, identify and characterize pathogenic bacteria from Erysipelothrix rhusiopathiae suspected cases or dead pigs from 8 different areas in Anhui Province. [Methods] The morphological, culture characteristics, biochemical test, PCR were applied to determine them, and then the drug-sensitivity test and protective immunity test were done. [Results] Twenty-nine E. rhusiopathiae strains were isolated; they were the same in morphological and biochemical properties. They were highly sensitive to Ampicillin and Cefatriaxone with 100% inhibitory among 18 antibiotics by drug-sensitivity test. The inhibition of Penicillin, Erythomycin and Cefotaxime was 93%, 89.7%, 75.9% respectively, though resistance to the other 13 antibiotics developed at different degree. The 8 isolates from different areas were highly lethal to mice, with LD50 between 14.30×102 and 2.36×102 CFU/mL. After immunized with commercial attenuated vaccine E. rhusiopathiae G4T10 strain through neck hypodermic injection, and challenged with 100 LD50 by lumbar injection, mice were 100% protected. [Conclusion] Isolated strains from different areas have the same biological characters, they were sensitive to beta lactam antibiotics. Commercial attenuated vaccine of G4T10 strain of E. rhusiopathiae can induce immune response to resist it.

Key words:Erysipelothrix rhusiopathiae, Isolation and identification, Biological characterization, Mice, Protective immunity