Coloured scanning electron micrograph (SEM) of Streptococcus pneumoniae , Gram-positive, encapsulated, coccus prokaryote (dividing). Causes (lower respiratory infection) pneumonia and (upper respiratory infections) bronchitis, laryngitis, sinusitis, and otitis media (middle ear infection). Magnification: x4, 400 when shortest axis printed at 25 millimetres.