TitleStructural and metabolic responses of Staphylococcus aureus biofilms to hyperosmotic and antibiotic stress.
Publication TypeJournal Article
Year of Publication2018
AuthorsKiamco MM, Mohamed A, Reardon PN, Marean-Reardon CL, Aframehr WM, Call DR, Beyenal H, Renslow RS
JournalBiotechnol Bioeng
Volume115
Issue6
Pagination1594-1603
Date Published2018 Jun
ISSN1097-0290
Abstract

Biofilms alter their metabolism in response to environmental stress. This study explores the effect of a hyperosmotic agent-antibiotic treatment on the metabolism of Staphylococcus aureus biofilms through the use of nuclear magnetic resonance (NMR) techniques. To determine the metabolic activity of S. aureus, we quantified the concentrations of metabolites in spent medium using high-resolution NMR spectroscopy. Biofilm porosity, thickness, biovolume, and relative diffusion coefficient depth profiles were obtained using NMR microimaging. Dissolved oxygen concentration was measured to determine the availability of oxygen within the biofilm. Under vancomycin-only treatment, the biofilm communities switched to fermentation under anaerobic condition, as evidenced by high concentrations of formate (7.4 ± 2.7 mM), acetate (13.1 ± 0.9 mM), and lactate (3.0 ± 0.8 mM), and there was no detectable dissolved oxygen in the biofilm. In addition, we observed the highest consumption of pyruvate (0.19 mM remaining from an initial 40 mM concentration), the sole carbon source, under the vancomycin-only treatment. On the other hand, relative effective diffusion coefficients increased from 0.73 ± 0.08 to 0.88 ± 0.08 under vancomycin-only treatment but decreased from 0.71 ± 0.04 to 0.60 ± 0.07 under maltodextrin-only and from 0.73 ± 0.06 to 0.56 ± 0.08 under combined treatments. There was an increase in biovolume, from 2.5 ± 1 mm to 7 ± 1 mm , under the vancomycin-only treatment, while the maltodextrin-only and combined treatments showed no significant change in biovolume over time. This indicated that physical biofilm growth was halted during maltodextrin-only and combined treatments.

DOI10.1002/bit.26572
Alternate JournalBiotechnol. Bioeng.
PubMed ID29460278
PubMed Central IDPMC5959008
Grant ListT32 GM008336 / GM / NIGMS NIH HHS / United States