Characterizing Salmonella fecal shedding among racehorses in Louisiana

Salmonella is an important intestinal pathogen in horses capable of infecting populations without demonstrating clinical illness. This study was performed to determine the prevalence of Salmonella fecal shedding among racehorses in Louisiana. Three serial fecal samples were collected from 429 Thoroughbred horses housed at four racetracks. Feces were tested for Salmonella by microbiologic culture with selective primary enrichment and delayed secondary enrichment (DSE). Samples were also evaluated for the presence of Salmonella by polymerase chain reaction (PCR) using genus-specific oligonucleotide primers. A total of 7 (1.6%) horses were positive for Salmonella by either primary bacterial culture or DSE and an additional 2 horses (0.5%) were positive for Salmonella by PCR. The combined prevalence of Salmonella fecal shedding from among all the horses in this study was 2.1%. The results of this study suggest that the prevalence of fecal shedding of Salmonella among racehorses in Louisiana is low.