Phage Co-infection: Can Bacteria Be Infected by Multiple Phages?

Yes, bacteria can be co-infected by multiple phages simultaneously. Outcomes depend on phage species, bacterial host, and multiplicity of infection (MOI).

Possible Outcomes

• Lytic cycle for both: Both produce progeny; high MOI accelerates lysis.
• Lysogenization by one: One phage integrates as prophage; the other enters lytic cycle.
• Recombination: Phage genomes recombine, generating novel variants.
• Superinfection exclusion (SIE): One phage blocks replication of the other; a bacterial defense.
• Pseudolysogeny: Temporary DNA integration without generational transmission.

Co-infections influence phage replication, host fitness, infection dynamics, and bacterial defenses, playing roles in phage evolution and ecology.