[Construction of aerobactin and sit operon mutant of avian pathogenic Escherichia coli E058 and evaluation of its pathogenicity].

OBJECTIVE: To elucidate the pathogenesis role of the vir region of APEC 02 strain E058.
METHODS: The gene aerobactin/sitABC operon knockout mutants E058deltavir of APEC E058 strain was generated using Red recombination system. A series of pathogenicity tests including chick embryo inoculation, the competition experiment and the colonization and persistence in vivo were used to evaluate the pathogenicity of APEC E058deltavir and the wild-type strain E058.
RESULTS: E058deltavir was similar to its parental strain E058 in the growth curves, invasion assays of HD-11 cell and in vitro competition assay. In the colonization and persistence test, the recovery colonies of E058deltavir were significantly decreased in all of the organs tested (P < 0.001).
CONCLUSIONS: These results indicate that the virulence factors encoded by aerobactin/sit operon genes were important for the pathogenesis of APEC E058.