Growth and acetate metabolism of Staphylococcus aureus in defined medium

TL;DR

This study explores how Staphylococcus aureus grows and uses acetate in a defined medium, identifying factors that affect its metabolism.

Contribution

The study identifies the role of specific enzymes and the amino acid-to-glucose ratio in acetate catabolism in Staphylococcus aureus.

Findings

Acetate catabolism in Staphylococcus aureus depends on acetyl-CoA synthetase, AcuA acetylase, and AcuC deacetylase.

A critical ratio of amino acids to glucose is necessary for complete oxidation of carbon sources in the medium.

The defined medium (CDM) helps ensure accurate metabolic studies during post-exponential growth.

Abstract

Staphylococcus aureus is a major human pathogen that has emerged as a model pathogen to study growth and metabolism. Many investigators have designed defined media (complete defined medium; CDM) to investigate staphylococcal genetic and metabolic processes. Previous S. aureus growth studies have found that acetate is not consumed following glucose catabolism in certain CDM recipes, nor are arginine and proline consumed, suggesting a defect in post-exponential growth. The current studies found that acetate catabolism is dependent upon the coordinated action of acetyl-CoA synthetase (Acs), the AcuA acetylase, and AcuC deacetylase. Furthermore, it was determined that acetate catabolism in S. aureus in CDM is linked to a critical ratio between the concentration of amino acids and glucose. These studies will help inform S. aureus metabolic experiments to ensure complete oxidation of carbon sources in the medium and therefore interrogate metabolism of the post-exponential phase.

Growth characteristics are critical to the study of Staphylococcus aureus metabolism and genetics. These studies have defined a critical concentration of amino acids and glucose that is required to ensure the complete oxidation of acetate and amino acids found in the medium. The complete defined medium (CDM) described in these studies will be used to inform future studies to ensure phenotypic and genotypic characteristics that are observed during post-exponential growth can be assessed.

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