Color enhanced transmission electron micrograph (TEM) of Streptococcus pneumoniae, also known as Pneumococcus. Streptococcus pneumoniae is a common host found in the mucosa of the mouth and pharynx. Under certain conditions, it can become the causal agent of pneumonia, meningitis, septicemia and otitis. Pneumococci are small round-shaped Gram-positive bacteria which generally form pairs (diplococci). They have a protective capsule preventing phagocytosis. Magnification 50,000x at 10 cm.