Toxic shock due to Streptococcus pyogenes in a rhesus monkey (Macaca mulatta)

Recent years have seen a worldwide resurgence in serious infections caused by group A streptococci. This group includes Streptococcus pyogenes, one of the most common pathogens among children which causes diverse suppurative infections, such as pharyngitis, as well as nonsuppurative infections with sequelae, such as rheumatoid fever and rheumatic heart disease. S. pyogenes produces several superantigen-like erythrogenic toxins, which are believed to be associated with pyrogenicity, erythromatous skin reactions, and various immunologic and cytotoxic effects. These toxins also can cause myocardial necrosis. In addition, recently reported streptococcal infections in obstetric human patients appear to be clinically different from classic puerperal sepsis. Here, we report a case of spontaneous streptococcal infection in a pregnant female rhesus monkey (Macaca mulatta). In addition to lesions consistent with bacteremia and toxic shock, this animal had severe cardiac lesions resembling those described in humans with rheumatic heart disease. S. pyogenes was isolated from intracardiac blood, liver, placenta, and fetal tissues. This isolate also had a unique M protein gene.