Lysogens of phi13 at secondary attachment sites in S. aureus 8325-4attBmut carrying a CC398-like bacterial attachment sites

Virulence gene carrying phage phi13 is found in almost all human-associated strains of Staphylococcus aureus but its integration in livestock-associates strains of CC398 is hindered due to a mutation in the bacterial attachment site (attB), recognized by the phage. We lysogenized laboratory strain S. aureus 8325-4attBmut, carrying a mutation in attB to resemble the attB-sequence of S. aureus CC398. We sequenced the whole genome of 22 lysogens to determine the alternative integration sites of the phage. We further induced the phages from the alternative sites and deep sequenced PCR amplicons spanning attP in phi13-lysates.