Impact of Antibiotics with Various Target Sites on the Metabolome of Staphylococcus aureus

Abstract

In this study, global intra-and extracellular metabolic profiles were exploited to investigate the impact of antibiotic compounds with different cellular targets on the metabolome of Staphylococcus aureus HG001. Primary metabolism was largely covered, yet uncommon staphylococcal metabolites were detected in the cytosol of S. aureus, including sedoheptulose-1,7-bisphosphate and the UDP-MurNAc-pentapeptide with an alanine-seryl residue. By comparing the metabolic profiles of unstressed and stressed staphylococcal cells in a time-dependent manner, we found far-ranging effects within the metabolome. For each antibiotic compound, accumulation as well as depletion of metabolites was detected, often comprising whole biosynthetic pathways, such as central carbon and amino acid metabolism and peptidoglycan, purine, and pyrimidine synthesis. Ciprofloxacin altered the pool of (deoxy)nucleotides as well as peptidoglycan precursors, thus linking stalled DNA and cell wall synthesis. Erythromycin tended to increase the amounts of intermediates of the pentose phosphate pathway and lysine. Fosfomycin inhibited the first enzymatic step of peptidoglycan synthesis, which was followed by decreased levels of peptidoglycan precursors but enhanced levels of substrates such as UDP-GlcNAc and alanine-alanine. In contrast, vancomycin and ampicillin inhibited the last stage of peptidoglycan construction on the outer cell surface. As a result, the amounts of UDP-MurNAc-peptides drastically increased, resulting in morphological alterations in the septal region and in an overall decrease in central metabolite levels. Moreover, each antibiotic affected intracellular levels of tricarboxylic acid cycle intermediates.

Staphylococcus aureus Infection Reduces Nutrition Uptake and Nucleotide Biosynthesis in a Human Airway Epithelial Cell Line

“…For LC-MS analysis a time of flight (micrOTOF) mass spectrometer (Bruker Daltonik, Bremen, Germany) was used with a setup as described [62]. In brief, we used a SymmetryShield RP18 column (Waters) and used an aqueous mobile phase with tributylamine as ion-pairing reagent and methanol as a second mobile phase.…”

“…Derivatisation method, type of column and oven program were optimized to analyse mainly small polar compounds such as amino acids, carbohydrates and organic acids. For identification and quantification of metabolites a GC-MS method was used as described [62]. Qualitative and quantitative analysis were performed using ChromaTOF software (LECO Corporation, St. Joseph, MI, USA).…”

Bacillithiol: a key protective thiol inStaphylococcusaureus

“…In a recent metabolomics study, a S. aureus NCTC 8325 derived natural bsh C mutant strain (HG001) was treated with fosfomycin and UDP-GlcNAc, GlcNAc-Mal, GlcN-Mal levels were observed by LCMS [51]. Interestingly, fosfomycin treatment significantly increased levels of UDP-GlcNAc (3.4-fold) and GlcNAc-Mal (the product of BshA, 2.2-fold), but levels of GlcN-Mal (product of BshB) were similar to treatment by the other drugs tested (ciprofloxacin, erythromycin, vancomycin and ampicillin).…”

“…Treatment of S. aureus with fosfomycin, which targets peptidoglycan biosynthesis by inhibiting MurA and MurZ, has been shown to increase levels of UDP-GlcNAc, the substrate of BshA [51]. This accumulation of a BshA substrate could hinder the ability of a potential competitive inhibitor to effectively block BshA activity and decrease bacillithiol levels.…”

Omics Approaches for the Study of Adaptive Immunity to Staphylococcus aureus and the Selection of Vaccine Candidates

“…First studies show the potential of these technologies [112,188,189,190,191]. For example, Krismer et al used a combined metabolomics and transcriptomics approach to explore the adaptation of S. aureus during colonization of the human nose [112].…”