Development of in-house indirect enzyme linked immunosorbent assay (iELISA) for detection of Salmonella enteritidis dpecific antibodies in poultry

Abstract

Salmonella enteritidis is a most important pathogenic bacterium of avian and mammals. Salmonella Enteritidis is the main cause of Salmonellosis in poultry flocks. S. enteritidis majorly infects the chicks, eggs and vertically transmitted to their off springs. The majority of the food infections to the humans are caused by salmonella by eating chicken meat and eggs. Monitoring of poultry farms with the bacteriological methods were time consuming and labour intensive process. The present study was development an in-house indirect enzyme linked immunesorbent assay (iELISA) for the detection of antibodies against Salmonella enteritidis in chicken serum samples. For detection of antibodies, Salmonella enteritidis LPS was used as antigen and rabbit anti chicken IgG HRP was used as the secondary antibody to detect antibodies against Salmonella enteritidis . The developed in-house ELISA was compared with the Rapid plate agglutination test. The purified LPS antigen 200ng/well, test sample serum at a dilution of 1:100 and rabbit anti chicken IgG HRP 1:10000 were used as optimal concentration of the assay and OD was measured at 450nm. A total of 1020 chicken serum samples were collected and performed the assay along with known Positive and negative controls. Out of these samples 592 and 566 samples were seropositive with iELISA and RPA respectively. Out of 1020 samples 58% samples shown positive immune response with iELISA and 55.6% samples were shown positive immune response to Rapid plate agglutination assay. The major prevalence of SE antibodies against SE antigen were shown in 20-25 weeks birds was 65.5%.The findings suggested that an in-house indirect ELISA based on S.enteritidis LPS can be a useful as a rapid and sensitive assay for the detection of antibodies to S.enteritidis and can be best assay for regular monitoring of Salmonella Enteritidis infection in flocks.