Skip to main content
ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Food Safety and Enteric Pathogens Research » Research » Publications at this Location » Publication #66328
Title: DEVELOPMENT OF AN ELISA FOR THE DETECTION OF SWINE EXPOSED TO SALMONELLA SPP.

Author
item GRAY, J - 3630-14-00
item CRAY, PAULA - 3630-14-00

Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: 5/23/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The pre-harvest detection of animals infected with Salmonella spp. is a critical step for the reduction of this pathogen. An indirect ELISA (designated SalAD), was developed to detect antibodies in swine which have been exposed to Salmonella spp. Heat extracted surface membrane antigens were combined from S. typhimurium (B), S. enteritidis (D1), S. anatum (E1), ,and S. choleraesuis (C1) representing serogroups most often isolated from swine. Antigen was prepared by heating cells from each serotype for 1 h at 60 deg C and filtering the supernatant. Immunlon 4 plates were coated with 4 ug (1 ug/serotype) of protein antigen. After blocking, swine serum was added (1:25 dilution) for 1 h. Swine antibodies were labeled with peroxidase conjugated anti-swine IgG antibody, the plates were washed and peroxidase substrate was added. The plates were read at an absorbance of 450 nm (410 reference). The sensitivity of the test was evaluated against sera from experimentally infected, long-term carrier swine and known infected swine herds. The specificity of the test was evaluated using sera from swine free of Salmonella spp., swine which had been infected but cleared the bacteria, and swine infected with E. coli or Yersinia enterocolitica (negative for Salmonella spp.). Preliminary tests indicate that the sensitivity and specificity are > 95% and > 85%, respectively. False positives were not obtained from pigs infected or vaccinated with E. coli. When compared to a Salmonella lipopolysaccharide-based ELISA, this test had a higher specificity. The SalAD is a useful test for monitoring the level of Salmonella infections in swine herds.