Recovery of Salmonella bacterial isolates from pooled fecal samples from horses.
Authors: Goni Jose I, Hendrix Kenitra, Kritchevsky Janice
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary Determining whether horses are shedding *Salmonella* spp. is clinically important, yet comprehensive culture protocols requiring multiple individual samples per horse can prove prohibitively expensive in practice settings. Jose and colleagues investigated whether pooling fecal samples could maintain diagnostic sensitivity whilst reducing costs, using both artificially spiked samples and clinical submissions from hospitalised horses. In controlled experiments, pooled samples successfully detected *Salmonella* concentrations as low as 10² colony-forming units, with the addition of 20 mL broth to pooled samples significantly improving recovery; crucially, all five horses identified as *Salmonella*-positive by individual culture were also detected via pooled sample analysis. This finding suggests that clinicians can confidently pool up to five 10-gram fecal samples per horse without sacrificing diagnostic sensitivity, potentially reducing laboratory costs substantially whilst maintaining reliable identification of shedding animals—a particularly valuable approach when screening populations at risk or monitoring horses recovering from clinical salmonellosis.
Read the full abstract on PubMed
Practical Takeaways
- •Pooling 5 fecal samples for Salmonella culture offers significant cost savings without sacrificing diagnostic sensitivity, making it a practical screening approach for hospitalized horses
- •Standardize pooling protocols by adding 20 mL broth and combining 10-gram aliquots from 5 individual samples to optimize recovery rates
- •Use pooled sampling as a cost-effective initial screening method in settings where testing large numbers of horses for Salmonella shedding would otherwise be prohibitively expensive
Key Findings
- •Pooled fecal samples from 5 horses are as sensitive as individual cultures for detecting Salmonella shedding
- •A minimum concentration of 10² cfu/mL of Salmonella spp. could be recovered from spiked samples
- •Addition of 20 mL broth to pooled samples improved bacterial recovery, whereas homogenization time did not
- •Of 19 hospitalized horses tested, 5 (26%) were positive for Salmonella, with all positives detected in both pooled and individual samples