The phage integrase vector pIPI03 allows RecA -independent, site-specific labelling of Staphylococcus lugdunensis strains

• Novel tools for genetic manipulation of Staphylococcus lugdunensis.
• A phage integrase vector allows integration into the chromosome of many strains.
• pIPI03 integrates site-specifically, RecA-independently and irreversibly.
• Different versions allow labelling of S. lugdunensis for competitive growth experiments.

Staphylococcus lugdunensis is a coagulase negative staphylococcus that is a commensal of man and an opportunistic pathogen. A site-specific integrative plasmid for the use in S. lugdunensis was constructed and validated. The integrase gene ccrB of bacteriophage ϕSL01 together with its attachment site was cloned into the thermosensitive plasmid pIMAY. The resulting plasmid pIPI03 integrated RecA-independently, site-specifically and irreversibly into the S. lugdunensis chromosome. Two IPTG-inducible antibiotic resistance determinants were cloned into pIPI03 and the derivatives were used to construct strains suitable for competitive growth experiments in both in vitro and in vivo.