Phage satellites induced by virulent phages are mobilized by natural competence leading to phage resistance in a new host

More than two-thirds of Streptococcus thermophilus strains harbor a phage satellite structurally similar to Staphylococcus aureus pathogenicity islands (SaPIs). Virulent phages can trigger induction of these satellites, and their DNA can then be transferred into a new strain by natural competence, which enhances the recipient strain's resistance to virulent phages.