Color enhanced transmission electron micrograph (TEM) of Streptococcus pyogenes bacteria. Streptococcus pyogenes is a gram-positive, rounded or spherical (coccus) bacteria. Many humans may carry it harmlessly in their throat or nose. Pathogenic strains, however, cause skin infections such as impetigo, uterine infection after childbirth, and blood poisoning (septicemia). They also cause a sore throat, tonsillitis and middle ear infections (otitis media) in children. Streptococcus group A1 can also be a deadly form of flesh eating bacteria. Magnification 20,000x at 10 cm.