Comparison of GN Hajna and tetrathionate as initial enrichment for salmonellae recovery from swine lymph nodes and cecal contents collected at slaughter

An epidemiologic survey was conducted to determine the prevalence of salmon ellae in swine from 5 farms of an integrated swine operation. The purpose o f this study was to evaluate the recovery efficiencies for salmonellae from swine lymph nodes and cecal contents when GN Hajna and tetrathionate were compared as initial enrichments. Salmonellae were isolated from 61% of 645 pigs at slaughter; 324 positive cultures were from lymph nodes, and 224 wer e from cecal contents. Frequently, pigs had salmonellae isolated from both the lymph nodes and cecal contents. Total isolations, regardless of source, were similar for GN Hajna (247) and tetrathionate (301). There was no diff erence (P > 0.05) in the number of isolations from lymph nodes when GN Hajn a enrichment was compared with tetrathionate enrichment (174 vs. 150). Howe ver, there was a significant (P < 0.05) advantage of utilizing tetrathionat e when compared with GN Hajna for isolations from cecal contents (151 vs. 7 3).