Streptococcus is a genus of bacteria that are commonly found in the human body and the environment. These bacteria can be spherical in shape and often appear in chains. Some species of Streptococcus are harmless and part of the normal flora, while others can cause infections, such as strep throat, skin infections, and pneumonia. There are several groups of Streptococcus, including Streptococcus pyogenes, which is known for causing strep throat, and Streptococcus pneumoniae, which can lead to pneumonia and meningitis. Treatment for infections caused by these bacteria typically involves antibiotics, which can effectively eliminate the harmful strains.