El-Baz E., Elgaml A., Barwa R. IMPACT OF THE GLOBAL REGULATOR SARA ON TOXINS PRODUCTION IN STAPHYLOCOCCUS AUREUS

SarA regulation of toxins in S. aureus

Abstract

Staphylococcus aureus (S. aureus) is a Gram-positive bacterium that is responsible for many infectious diseases in human, some of which may be fatal. The regulation of toxins production and virulence factors in this pathogen is controlled by many global regulators including the staphylococcal accessory regulator, SarA. In this study, we outlined the influence of SarA on toxins production in S. aureus. The expression of genes encoding toxins was measured using real-time PCR and toxins production was quantitatively assayed. Gene expression and quantitative toxins production were compared in three staphylococcal strains; UAMS-1 wild type clinical strain, its sarA mutant strain and a revertant strain. Genes encoding for proteases (including sspA, aur, scpA and sspB), genes encoding for hyaluronidases (including hysA1 and hysA2) and gene encoding for staphylokinase (sak) were upregulated in response to the sarA mutation. On contrary, genes encoding for lipases (including lip1 and lip2) were downregulated. Moreover, the quantitative production of protease, hyaluronidase and staphylokinase was significantly increased due to the sarA mutation. On the other hand, the quantitative production of lipase was significantly altered. Overall, our findings indicate that SarA is an effective global regulator of toxins production that can suggest new prospective therapeutics for the treatment of S. aureus infections.