Streptococcal enteropathy in infant rats.

A spontaneous outbreak of enteric disease with high morbidity and mortality occurred in preweanling rats on a multigeneration toxicity study. The rats had a large number of gram-positive cocci on the surface of villi in the small intestine without associated inflammatory change. Ultrastructural study identified filamentous attachments between adjacent bacteria, and between bacteria and morphologically normal microvilli. The organism was isolated and identified as Streptococcus sp. The disease was reproduced in rat pups by inoculating dams and newborn rats with pure cultures of the Streptococcus. Streptococcal enteropathy is a previously unreported disease in rats.