TY - JOUR
T1 - Edwardsiella tarda mutants defective in siderophore production, motility, serum resistance and catalase activity
AU - Mathew, J. A.
AU - Tan, Y. P.
AU - Srinivasa Rao, P. S.
AU - Lim, T. M.
AU - Leung, K. Y.
PY - 2001
Y1 - 2001
N2 - Edwardsiella tarda is a Gram-negative bacterium that causes a systemic infection, edwardsiellosis, in fish. The virulence factors of this pathogen and its genetic determinants have not been systematically examined. In this study, TnphoA transposon mutagenesis was used to construct a library of 440 alkaline phosphatase (PhoA+) fusion mutants from a total of 400 000 transconjugants derived from Ed. tarda PPD130/91. This library included genes for secreted and membrane-associated proteins normally involved in virulence. The library was screened for four virulence factors: siderophore production, motility, serum resistance and catalase production. Eight mutants deficient in one or more of these phenotypes were grouped into four classes. They were further characterized for their stimulation of reactive oxygen intermediate production by fish phagocytes, for their adhesion to and internalization into EPC (epithelioma papillosum of carp) cells, and for attenuation of virulence in blue gourami. Mutants 2A and 34 were highly attenuated in fish, with LD50 values about 10 times higher than for the wild-type. These strains had mutations in the genes encoding arylsulfate sulfotransferase (mutant 2A) and a catalase precursor protein (mutant 34). One hyperinvasive/adhesive mutant and four pst mutants that were pleiotropic and slightly attenuated in fish were also isolated.
AB - Edwardsiella tarda is a Gram-negative bacterium that causes a systemic infection, edwardsiellosis, in fish. The virulence factors of this pathogen and its genetic determinants have not been systematically examined. In this study, TnphoA transposon mutagenesis was used to construct a library of 440 alkaline phosphatase (PhoA+) fusion mutants from a total of 400 000 transconjugants derived from Ed. tarda PPD130/91. This library included genes for secreted and membrane-associated proteins normally involved in virulence. The library was screened for four virulence factors: siderophore production, motility, serum resistance and catalase production. Eight mutants deficient in one or more of these phenotypes were grouped into four classes. They were further characterized for their stimulation of reactive oxygen intermediate production by fish phagocytes, for their adhesion to and internalization into EPC (epithelioma papillosum of carp) cells, and for attenuation of virulence in blue gourami. Mutants 2A and 34 were highly attenuated in fish, with LD50 values about 10 times higher than for the wild-type. These strains had mutations in the genes encoding arylsulfate sulfotransferase (mutant 2A) and a catalase precursor protein (mutant 34). One hyperinvasive/adhesive mutant and four pst mutants that were pleiotropic and slightly attenuated in fish were also isolated.
KW - Fish pathogen
KW - Transposon mutagenesis
KW - Virulence genes
UR - http://www.scopus.com/inward/record.url?scp=0035134462&partnerID=8YFLogxK
U2 - 10.1099/00221287-147-2-449
DO - 10.1099/00221287-147-2-449
M3 - 文章
C2 - 11158362
AN - SCOPUS:0035134462
SN - 1350-0872
VL - 147
SP - 449
EP - 457
JO - Microbiology (United Kingdom)
JF - Microbiology (United Kingdom)
IS - 2
ER -