LPS and Flagellin-Based Models for Serological Screening and Confirmation of Salmonella Infections in Chickens

Avian salmonellosis due to Salmonella B and D serogroups has a great importance because of the public health and the economical losses in poultry industry. For accurate diagnosis of avian salmonellosis, a total of 126 chicken sera evaluated with a commercial Salmonella Enteritidis (SE) ELISA kit have been used to develop two indirect ELISA models using lipopolysaccharide (LPS) and purified flagellin (Flg) of SE as diagnostic antigens. After optimization, 154 and 263 sera were tested with indirect LPSand Flg-ELISA, respectively. The performance of both indirect LPSand Flg-ELISA was found high and similar for detecting anti-Salmonella antibody in comparison with a commercial LPS-ELISA kit. Nevertheless, a limited number of chicken sera were found discordant between Flgand LPS-ELISAs. Western-blot analyses of the discordant sera demonstrated that they were found reactive with bacterial lysate of SE but only recognized LPS or Flg antigen. It was concluded from this study that the simultaneous use of both LPSand Flg-ELISAs would allow differential diagnosis of avian specific salmonellosis from zoonotic Salmonella infections due to flagellated bacteria and Western blot models can be used as confirmatory serological test. .