The dynamic detection of duck E.coli O_(46) distribution in organs of experimentally infected duckling by immunohistochemistry

To investigate the dynamic distribution of a pathogenic duck E.coli O46 strain in different organs of ducklings after experimental infection, the ducklings were inoculated with the E.coli O46 isolate via oral, intramuscular injection and subcutaneous routes, respectively. At different time points after infection, tissue samples were collected from 12 organs, and slices were prepared and tested by immunohistochemical assay with O46-specific antiserum to observe the bacterial antigen localizations in infected ducklings. The results showed that the bacterial antigen was detected in all organs except for trachea. Heart, lung, spleen kidney and intestinal tract were proven to be the main target tissues of the bacteria, and bacterial antigen mainly located in cytoplasm of infected cells. Positive signals were first detected in heart. The results obtained in this study suggested that the E.coli O46 strain isolated from duck has a broad tissue tropism, and therefore could lead to acute onset and death of the ducks.