Bacteria are capable of natural genetic transformation especially when they are under external selection pressure including vaccination or antibiotics treatment. The capability of the genetic transformation in Streptococcus pneumoniae,Streptococcus mitis and Streptococcus oralis are controlled by secreted peptide pheromones named Competence-Stimulating Peptide . Different strains and species of these bacteria produce CSP with different primary sequence. They are termed pheromones CSP-1 , CSP-2 (EMRISRIILDFLFLRKK), CSP-153 (DKRLPYFFKHLFSNRTK), CSP-612 (ESRLSRLLRDFIFQIKQ), CSP-676 (ERRIPDVIRSLLFQKRK), and CSP-12261 (EIRQTHNIFFNFFKRR).