Environmental Survival of S. equi

A recent study looked at how long S. equi remained in the environment on various surfaces that can be found in and around a horse stable. The research was titled, “A study of the environmental survival of Streptococcus equi subspecies equi” and was authored by  Durham, A. E.; Hall, Y.S.; Kulp, L.; and Underwood, C.

S. equi was inoculated onto wood, the rubber sole of a shoe, on cotton overalls, inside a nasogastric tube, on a dental rasp, on a wet plastic bucket and on an outdoor fence post. Samples were taken from all surfaces at 24-hour intervals for the first five days and at 48-hour intervals until Day 23, followed by bi‐weekly intervals until no viable bacteria could be cultured from two consecutive samplings. The protocol was carried out during both summer and winter months.

Bacterial growth and vigor was higher in wet conditions and during the winter. In winter, the longest period over which successful cultures of S. equi were obtained was 30 days from the wet bucket. In contrast, the longest period over which successful cultures were obtained in summer was seven days from the nasogastric tube.

The bottom line is that S. equi is likely to survive for longer periods in wet, humid and cold conditions, and it can survive for longer than previously thought.

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