Use of quantitative real-time PCR for the detection of Salmonella spp. in fecal samples from horses at a veterinary teaching hospital.

The research article focuses on the development of a quantitative Real-Time (RT)-PCR assay for detecting Salmonella spp. in horse fecal samples to reduce risk of nosocomial infections like salmonellosis in a veterinary hospital setting.

Experiment Setup and Process

• The research was performed on 911 horse species in a veterinary hospital. Fecal matter was collected both fresh and after enriching for 24 hours in selenite broth.
• The samples were then examined for Salmonella spp. existence using traditional culture methods, and with an RT-PCR assay designed to target the Salmonella invA gene.
• The RT-PCR assay was found to have a detection limit of 3 to 10 organisms when samples were purified from the selenite broth and feces, respectively.

Results and Findings

• The specificity of the RT-PCR assay was determined to be 100%, after detecting a panel of 40 different salmonella serotypes from five different serogroups, and showing no cross-reactivity with unrelated microorganisms.
• The Salmonella spp. was not found in fresh fecal matter but it was found in 0.6% of samples that were enriched in broth. The bacteria quantity ranged from 3 to 861,037 salmonella invA gene copies per μL of DNA.

Accuracy of RT-PCR Assay

• The overall accuracy of the RT-PCR assay was calculated to be 98% compared to traditional culture methods. It demonstrated a 100% sensitivity and 98% specificity.
• Such results imply that the RT-PCR assay shows great potential as a highly effective, swift method for detecting pathogenic organisms, minimizing the chances of a nosocomial infection such as salmonellosis.