What is streptococcus and what causes it ?

Streptococcus: It is a bacteria, there are different group of this bacteria ( group a, b, c...), some of them can cause pneumonia , sore throat ( strep throat), urinary tract infection etc..., you can get them from someone who is already infected , or breathing droplets(droplets from sneezing, coughing ) that are contains the bacteria, strep can cause , pink eye, meningitis, erysipela, "flesh-eating" infections.