Objectives—To assess methods of detecting environmental
contamination with Salmonella organisms
and evaluate a cleaning and disinfection protocol for
horse stalls in a veterinary teaching hospital.
Sample Population—37 horses with diarrhea likely
to be caused by Salmonella infection and their stall
Procedures—Fecal samples were collected from horses
daily during hospitalization; samples were obtained
from stall sites after cleaning and application of disinfectants.
Fecal and environmental samples were cultured
for Salmonella spp and tested via polymerase
chain reaction (PCR) assay to detect Salmonella DNA.
Results—1 horse died and 2 were discharged prior to
sample collection. Fecal samples from 9 of 34 horses
yielded growth of Salmonella organisms on bacteriologic
culture, and 23 yielded positive results via PCR
assay on ≥ 1 occasion. Among environmental samples
from 21 stalls, salmonellae were detected at ≥ 1 stall
site on 6 of 78 occasions, and ≥ 1 stall site yielded positive
results via PCR assay on 69 of 77 occasions.
Salmonella DNA was detected more frequently in samples
of stall drains, cracks, and corners. Salmonella spp
were cultured from samples of 3 stalls after both initial
and second cleaning and disinfection cycles, but no
organisms were detected in samples obtained after
use of a peroxygen disinfectant.
Conclusions and Clinical Relevance—Results suggest
that stalls in which horses with salmonellosis were
housed should only be used to accommodate newly
hospitalized horses after samples (collected after 2
cycles of cleaning and disinfection) from drains, cracks,
and corners yield negative results on bacteriologic culture.
(J Am Vet Med Assoc 2003;223:1640–1644)