Preparation and evaluation of Salmonella Enteritidis antigen conjugated with nanogold for screening of poultry flocks

AIM: The present work aimed to develop lateral flow immunochromatographic strip (ICS) test for detection of Salmonella Enteritidis (SE) specific antibodies in chicken sera. MATERIALS AND METHODS: A rapid lateral flow immunochromatographic test (LFIT) has been developed, in which SE Group D antigen labeled with the gold chloride molecules laid on the conjugate pad. Staphylococcus aureus protein A was used as capture antibody at the test line (T) of a nitrocellulose (NC) membrane and anti-SE antigen-specific rabbit antibodies were used as capture antibody at the control line (C) of the NC strip in the lateral flow layout device. RESULTS: Using the developed LFIT, the minimal amount of SE-specific antibodies that can be detected in chicken serum sample was 1427 enzyme-linked immunosorbent assay (ELISA) unit/100 µl that was equal to 0.1 µg (Ab)/100 µl sample. 100 suspected serum samples collected from a poultry flock were tested with the prepared SE-LFIT kits and the locally prepared stained Salmonella antigen, and the results were compared with those obtained from examination of these samples with Salmonella Group D antibody ELISA kit as the gold standard test. The sensitivity, specificity, and accuracy of the prepared SE-LFIT antigen kits were 94.4%, 90%, and 94%, respectively, while those obtained with stained Salmonella antigen were 88.8%, 90%, and 89%, respectively. CONCLUSION: The developed test is a simple field rapid test of high sensitivity, specificity, and accuracy that can improve and facilitates rapid field surveillance of salmonellosis among chickens.