Identification of a novel LysR-type transcriptional regulator in Staphylococcus aureus that is crucial for secondary tissue colonization during metastatic bloodstream infection

Purpose: The goal of this study was to identify Staphylococcus aureus genes which are important during establishment of metastatic infections in bloodstream infections. Methods: Pooled mariner transposon mutant libraries were generated as previously described (PMID: 27185949). The libraries were sequenced on the Illumina HiSeq 2500 platform with the transposon-specific oligonucleotide primer Himar1-Seq. Illumina adapter sequences were removed via cutadapt version 1.2.1. The reads were filtered for size (>16 bp) and to contain the signature transposon inverted repeat. Reads were mapped to the Staphylococcus aureus 6850 genome (RefSeq accession NC_022222.1) by Bowtie2 v2.1.0. Identification of depleted and enriched mutants was performed via DESeq2 version 1.6.2. Results: S. aureus genes were identified which were upregulated or downregulated upon iduced expression of the LysR-type transcriptional regulator RSAU_000852 in Staphylococcus aureus 6850. Conclusions: Our study identifies a gene for a LysR-type transcription regulator, which is involved in metabolic adaptation of the pathogen during colonization of secondary infection sites in a bloodstream infection model. S. aureus RNAseq was performed on wild-type S. aureus 6850, an RSAU_000852 deletion mutant, and a strain carrying anhydrous tetracycline-induced RSAU_000852 ORF. Experiments were performed in triplicates.