Strep throat can be a real pain in the neck, err, throat, and the streptococcus bacteria is to blame. Streptococcus has hundreds of different strains that are organized into group A and group B. Group A strep (GAS), or streptococcus pyogenes, causes strep throat, as well as scarlet fever [2] and impetigo [3]. Group B strep (GBS), or streptococcus agalactiae, causes blood infections, pneumonia, ...