Diagnosing salmonellosis in horses. Culturing of multiple versus single faecal samples.

This research was aimed at examining whether diagnosing salmonellosis in horses was more accurate with multiple faecal cultures rather than a single one.

Research Methodology

• The researchers took three rectal faecal samples from 136 horses, with each sample taken at a 24-hour interval.
• The horses were categorized into two groups: 89 horses suspected of having salmonellosis based on clinical symptoms, and 47 horses that served as a control group.

Results and Findings

• From the group suspected of salmonellosis, 22 horses were found to be Salmonella-positive, but only twelve of these tested positive at the first sampling.
• Within the control group, only three horses tested positive for Salmonella.
• Importantly, a larger portion (69%) of the positive cultures from the ‘Salmonella suspected’ group were detected only after enrichment in Selenite broth, a medium that enhances the growth of Salmonella bacteria.

Conclusions and Implications

• The researchers concluded that multiple faecal cultures are more reliable for diagnosing clinical salmonellosis in horses compared to single cultures.
• The course of the disease was not found to be related to whether the Salmonellae were cultured directly or indirectly, using Selenite broth.
• Salmonellae were still found in horses that had been treated with antibiotics prior to the study. This is even when the strain of Salmonella was susceptible to the antimicrobial drug prescribed by the vet, suggesting that antimicrobial treatment may not always effectively clear the infection.

This research significantly shows the importance of multiple testing in ensuring an accurate diagnosis, as well as the benefit of enriching samples in Selenite broth to boost detection rates of Salmonella in horses.