Transcriptional profiling and metabolomic analysis of Staphylococcus aureus grown on autoclaved chicken breast

Abstract

Although Staphylococcus aureus is a major cause of food poisoning, little is known about its response to growth on food. Utilizing a transcriptional profiling and metabolomics approach, we compared S. aureus grown on autoclaved chicken breast (ACB) to Luria broth agar. ACB cultures demonstrated increased expression of genes associated with protein synthesis, cofactors, secondary metabolites, nitrogen and nucleotide metabolism, amino acid transport, and reduced expression of general stress, lipid metabolism, and virulence genes. The ACB culture also displayed characteristics of catabolite de-repression and anaerobic growth, and increased expression of arginine biosynthesis genes (argFGH) and an arginine/ornithine antiporter gene (arcD). S. aureus synthesizes arginine from proline and the ACB culture exhibited increased expression of proline transport genes (opuBA, opuBB and putP) and increased proline accumulation. Amino acid and sugar content in the ACB grown culture increased, and this was attributed to the consumption of ACB, transport of amino acids, and gluconeogenesis. Genes involved with biotin biosynthesis and uptake were upregulated and biotin is required for amino acid catabolism. Genes encoding urease and urease activity were upregulated in ACB cultures, while urea levels were reduced. This research provides fundamental information on the response of S. aureus growing on chicken meat that could find application in future attempts to reduce the growth of S. aureus in food.

Keywords: Chicken; Metabolomics; S. aureus; Transcriptional profiling.