The present invention relates to compositions and methods of use comprising peptidyl-prolyl isomerase (PPI) polypeptides of group C and G streptococci and polynucleotides encoding same. The invention also relates to immunogenic compositions comprising the PPI polypeptides and polynucleotides, as well as antibodies and antibody fragments that bind the PPI polypeptides. In addition, the invention relates to methods of inducing an immune response in a subject against beta hemolytic streptococci using the immunogenic compositions, as well as conferring passive immunity by administering a therapeutic antibody or antibody fragment.