| Summary: | 碩士 === 國立屏東科技大學 === 獸醫學系 === 93 === Lactococcus garvieae is a zoonotic pathogen and rare pathogen with a
low virulence in human infection. In Taiwan, it causes infection grey mullet
and giant freshwater prawn during summer. Gross pathological showed
clouding of cornea, splenomegaly and external haemorrhage.
Histopathologically, they showed meningoencephalitis. Physiological and
biochemical characteristics of all L. garvieae strains were Gram positive
cocci. Almost strains were able to grow at high temperature and media in high
salt and pH 9.6. The capsular type of L. garvieae were examined by capsule
stain. Capsular phenotype were found in all strains isolated from grey mullet
and non-capsular phenotype were found only in one strain isolated from giant
freshwater prawn in Taiwan. The phenotypic and genetic analysis results were
present for by rapid ID 32 STREP and pulsed field gel eletrophrosis ( PFGE ),
respectively. There was 9 phenotypes in L. garvieae isolated from grey mullet
and 11 phenotypes in Taiwan. However, L. garvieae from grey mullet
exhibited one genotype only and L. garvieae in Taiwan exhibited six
genotypes. The formalin-killed whole cell vaccines of L. garvieae
III
were prepared. Grey mullet were inoculated intraperitioneally with
formalin-killed whole cell vaccine from five strains of L. garvieae and
followed by a secondary IP injection after primary immunization. Increased
nitro blue tetrazolium activity were observed in 3 strains at 2 weeks after
primary immunization. However, decreased lysozyme activity were observed
in 3 strains at 2 weeks after primary immunization. Peaked antibody titer in
the serum of grey mullet were observed at week 6 and 8 after primary
immunization and agglutinating titer of 256 in grey mullet were observed. On
the cross reactivity, all antisera were not agglutinated capsulated Japanese
isolate except it’s homologous bacteria.
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