Streptococcus pneumoniae, also known as S. pneumoniae, is a prokaryotic organism with spearhead-shaped bodies arranged in pairs, with a diameter of 0.5-1.5 nm. S. pneumoniae is a septic, Gram-positive bacillus that is Gram-stain positive. S. pneumoniae is round, has no tooth buds and no flagella, and forms a scab membrane in the body. S. pneumoniae usually accumulates in the nasopharynx or oral cavity of normal individuals, most are not pathogenic, and very few patients will be pathogenic. Pathogenic S. pneumoniae can cause lobar pneumonia, peritonitis, pleurisy, otitis media, mastoiditis, and sepsis. The common form of lobar pneumonia is caused by S. pneumoniae, but S. pneumoniae is rarely resistant in nature and is sensitive to most antibiotics.