Evaluation of RapidChek® SELECTTM for the detection of Salmonella spp. in environmental samples from a veterinary hospital

Nosocomial salmonellosis in hospitalized animals is a recognized hazard, especially in large animal clinics. A standardized culture protocol (SCP) for detecting Salmonella spp. in environmental samples using a 48-h enrichment step results in a 5-day turnaround time for negative results. The RapidChek (R) SELECTTM Salmonella (RCSS) test system offers detection of organisms in 22-44 h through double enrichment followed by a lateral flow immunoassay. Negative results are reported within 48 h. To determine the most sensitive and rapid method for detecting Salmonella spp. from environmental samples collected at the large animal Purdue Veterinary Hospital (LA-PVH), a preliminary study compared the performance of RCSS and a SCP when testing artificially spiked and naturally contaminated samples. An expanded study analyzed results obtained using the RCSS method to test 872 environmental samples over a 12-month period. Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry was chosen as the confirmation method for RCSS-presumptive positive samples. A randomly selected subset of samples received additional confirmation by real-time PCR. Here, we reported the performance data of RCSS in terms of sensitivity, specificity, and positive predictive value using MALDI-TOF results as reference for comparison. We also provide guidelines for reporting results obtained using this system.