 Therefore, Aca activity is essential to ensure its survival.Moreover, it has been verified that bacteria with CRISPR-Cas systems are still partially immune to Acr.Consequently, initial abortive phage infections may be unable to hamper CRISPR immunity, but phage-phage cooperation can increasingly boost Acr production and promote immunosuppression, which might produce an increase on the vulnerability of the host cell to reinfection, and finally allow a successful infection and spreading of a second phage.