Influence of iron and aeration on Staphylococcus aureus growth, metabolism, and transcription

Nagender Ledala, Bo Zhang, Javier Seravalli, Robert Powers, Greg A Somerville

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Staphylococcus aureus is a prominent nosocomial pathogen and a major cause of biomaterial-associated infections. The success of S. aureus as a pathogen is due in part to its ability to adapt to stressful environments. As an example, the transition from residing in the nares to residing in the blood or deeper tissues is accompanied by changes in the availability of nutrients and elements such as oxygen and iron. As such, nutrients, oxygen, and iron are important determinants of virulence factor synthesis in S. aureus. In addition to influencing virulence factor synthesis, oxygen and iron are critical cofactors in enzymatic and electron transfer reactions; thus, a change in iron or oxygen availability alters the bacterial metabolome. Changes in metabolism create intracellular signals that alter the activity of metabolite-responsive regulators such as CodY, RpiRc, and CcpA. To assess the extent of metabolomic changes associated with oxygen and iron limitation, S. aureus cells were cultivated in iron-limited medium and/or with decreasing aeration, and the metabolomes were examined by nuclear magnetic resonance (NMR) spectroscopy. As expected, oxygen and iron limitation dramatically decreased tricarboxylic acid (TCA) cycle activity, creating a metabolic block and significantly altering the metabolome. These changes were most prominent during post-exponential-phase growth, when TCA cycle activity was maximal. Importantly, many of the effects of iron limitation were obscured by aeration limitation. Aeration limitation not only obscured the metabolic effects of iron limitation but also overrode the transcription of iron-regulated genes. Finally, in contrast to previous speculation, we confirmed that acidification of the culture medium occurs independent of the availability of iron.

Original languageEnglish (US)
Pages (from-to)2178-2189
Number of pages12
JournalJournal of bacteriology
Volume196
Issue number12
DOIs
StatePublished - 2014

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Staphylococcus aureus
Iron
Growth
Oxygen
Metabolome
Citric Acid Cycle
Virulence Factors
Food
Metabolomics
Biocompatible Materials
Culture Media
Magnetic Resonance Spectroscopy
Electrons
Infection

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

Cite this

Influence of iron and aeration on Staphylococcus aureus growth, metabolism, and transcription. / Ledala, Nagender; Zhang, Bo; Seravalli, Javier; Powers, Robert; Somerville, Greg A.

In: Journal of bacteriology, Vol. 196, No. 12, 2014, p. 2178-2189.

Research output: Contribution to journalArticle

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