Evaluation of two commercially available ELISA test kits for detection of Salmonellae in swine lymph nodes and cecal and fecal contents

We conducted a survey to determine the prevalence of salmonellae in pigs in an integrated swine operation. Isolation of salmonellae from lymph nodes, cecal contents, and fecal samples was by routine microbiological culture techniques. Simultaneously, and using the same samples, we evaluated two commercially available ELISA-based Salmonella test systems (Neogen Reveal and EiaFosslM) for detection of salmonellae and compared these results to our culture results. The advantages of the Neogen test were that it was simple to use and had up to an 87% agreement with culture. The disadvantages of the Neogen test were that it was expensive, it was not suitable for cecal or fecal samples (cross-reacted with Citrobacter spp.), it had a high rate of false negatives, and positive endpoints were subjective and difficult to read. The advantages of the Foss test were that it had up to a 93% agreement with culture results, it had low rates of false negatives and false positives, it was applicable for cecal and fecal samples, and it reduced time and labor compared to culture procedures. The disadvantages of the Foss test were that it required purchase of an expensive auto analyzer and not all of the 3 protocols recommended by the manufacturer were equally effective in recovery of salmonellae. We concluded that under our study conditions, the Neogen test was not acceptable, but that the Foss system was suitable for detection of salmonellae from field samples