Comparison of two sampling and culture systems for detection of Salmonella enterica in the environment of a large animal hospital.
Authors: Ruple-Czerniak A, Bolte D S, Burgess B A, Morley P S
Journal: Equine veterinary journal
Summary
# Editorial Summary: Environmental Salmonella Detection in Large Animal Hospitals Nosocomial salmonellosis remains a significant infection control challenge in equine and large animal hospitals, necessitating reliable methods for identifying environmental contamination during outbreak investigations and prevention programmes. Researchers compared two distinct sampling and culture protocols by collecting paired environmental samples from 100 stalls housing horses, cattle or camelids confirmed to be shedding *Salmonella enterica*—one using sterile pre-moistened sponges with thioglycolate enrichment, the other employing electrostatic wipes with multiple selective enrichment broths (buffered peptone water, tetrathionate and Rappaport-Vassiliadis R10). The electrostatic wipe method detected *Salmonella* in 14% of samples compared to only 4% for the sponge technique, with statistically significant disagreement between methods on 12 sample pairs despite both stalls being cleaned and disinfected prior to sampling. These findings indicate that environmental salmonellae persist stubbornly even after rigorous decontamination protocols, making sensitive detection methodology essential for effective outbreak management and nosocomial infection control. Farriers and equine practitioners involved in hospital infection prevention should be aware that sampling technique substantially influences detection success; facilities implementing surveillance programmes should preferentially adopt the more sensitive electrostatic wipe and multi-broth enrichment approach to ensure genuinely effective environmental monitoring.
Read the full abstract on PubMed
Practical Takeaways
- •When investigating Salmonella contamination in your facility, use electrostatic wipe sampling with multiple enrichment culture methods as it is significantly more sensitive (3.5x higher detection rate) than sponge sampling
- •Standard cleaning and disinfection alone may not eliminate Salmonella from hospital environments; sensitive environmental monitoring is essential for outbreak detection and control
- •Consider implementing the more sensitive sampling protocol when dealing with confirmed Salmonella shedders or investigating potential nosocomial spread in your hospital
Key Findings
- •Electrostatic wipe sampling detected S. enterica in 14% of paired samples compared to 4% with sponge sampling method
- •Significant disagreement between the two detection methods was observed in 12 pairs of discordant results (P<0.01)
- •Salmonella persisted in hospital environment even after rigorous cleaning and disinfection
- •Electrostatic wipe method with multiple enrichment broths (buffered peptone water, tetrathionate, Rappaport-Vassiliadis R10) was more sensitive than sponge method with single thioglycolate enrichment