Streptococcus is a genus of bacteria that are commonly found in the human body and the environment. These bacteria are 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 types of Streptococcus, categorized mainly into groups based on their ability to break down red blood cells. For example, Streptococcus pyogenes is known for causing strep throat, while Streptococcus pneumoniae can lead to pneumonia and meningitis. Proper hygiene and medical treatment can help manage infections caused by these bacteria.