“The rougher surface of the polyester material may make the polyester halters more amenable to S. equi survival in the presence of cleaning and sanitation compared to the others,” said Anneli Rydén, PhD candidate, a veterinary nurse and lecturer in veterinary nursing in the Swedish University of Agricultural Sciences Faculty of Veterinary Medicine, in Uppsala. “Hence, it appears that ensuring a washing temperature of (at least) 60°C (140°F) is necessary to eliminate live S. equi in fabrics such as polyesters.”
In their study, Rydén and her fellow researchers tested barn equipment in a laboratory setting, before and after subjecting items to various cleaning techniques. They experimentally contaminated wood, plastic, and concrete samples, as well as leather and nylon halters and leather gloves, with S. equi. They allowed the bacteria to grow for four days and then cleaned half the equipment. The other half they left uncleaned as a control for comparison.
Wiping down the wood, plastic, and concrete with soap, water, and a basic disinfectant eliminated all the bacteria, Rydén said. The untreated surfaces had just as high a level of S. equi contamination as before, even two days later.
S. equi disappeared spontaneously from the leather gloves and halters in the control group over a six-day period, they said. The bacteria did not survive on the leather after cleaning and disinfecting, either.
“Leather, even in unwashed states, may poorly support survival of S. equi, and this has key consequences for the management and care of leather bridles and saddles,” said Miia Riihimäki, PhD, also of the Swedish University of Agricultural Sciences Faculty of Veterinary Medicine.
By contrast, S. equi contamination was just as high after machine washing the nylon halters on warm (40°C, or 104°F) as before, the researchers found. Even adding a machine tumble dry cycle did no good—the nylon’s bacterial presence remained the same.
It was only when they washed the halter fabric at 60°C (140°F) that washing became effective at destroying all the bacteria, they said, leaving the nylon S. equi-free.
This study showed that owners can defeat the strangles bacteria through proper cleaning and disinfecting, Riihimäki and Rydén said. They said that for most surfaces, success requires “the physical removal of visible organic material and the use of an appropriate detergent, together with a disinfectant that is proven to act against S. equi.”
And with nylon, handlers must rely on machine washing on hot at a temperature of at least 60°C (140°F) to beat the bacteria.
“The surfaces best-suited for successful disinfection obviously are nonporous materials,” Rydén said. “However, the results in our study demonstrate that the chosen method for cleaning and sanitation can destroy the bacteria even in unsuitable materials such as raw wood and concrete.”
The study, “Effectiveness of Cleaning And Sanitation Of Stable Environment and Riding Equipment Following Contamination with Streptococcus equi,” was published in the Equine Veterinary Journal.