β-Hemolytic Streptococcus

Etiology:  β-Hemolytic Streptococci are Gram-positive cocci.  This bacterium is considered a low-grade opportunist.

Incidence:  The incidence of infection is rare.

Transmission:  Transmission occurs through direct contact with infective nasopharyngeal secretions.  Streptococci may be spread from humans to animals.

Clinical Signs:  No signs of clinical disease have been reported in immunocompetent rats. This bacterium is a low-grade opportunist, and overgrowth can occur when there are extreme stressors associated with experimental manipulation, compromise of the immune system or undetermined factors associated with specific colonies of genetically engineered animals [3].

Diagnosis:  Diagnosis should be made by culture of the organism in conjunction with the presence of other clinical signs.


  1. Shuster, K. A., et al., Naturally Occurring Disseminated Group B StreptococcusInfections in Postnatal Rats. Comp Med, 2013. 63(1): p. 55-61.