Global Metabolic Response of Enterococcus faecalis to Oxygen

Abstract

cOxygen and oxidative stress have become relevant components in clarifying the mechanism that weakens bacterial cells in parallel to the mode of action of bactericidal antibiotics. Given the importance of oxidative stress in the overall defense mechanism of bacteria and their apparent role in the antimicrobial mode of action, it is important to understand how bacteria respond to this stress at a metabolic level. The aim of this study was to determine the impact of oxygen on the metabolism of the facultative anaerobe Enterococcus faecalis using continuous culture, metabolomics, and 13 C enrichment of metabolic intermediates. When E. faecalis was rapidly transitioned from anaerobic to aerobic growth, cellular metabolism was directed toward intracellular glutathione production and glycolysis was upregulated 2-fold, which increased the supply of critical metabolite precursors (e.g., glycine and glutamate) for sulfur metabolism and glutathione biosynthesis as well as reducing power for cellular respiration in the presence of hemin. The ultimate metabolic response of E. faecalis to an aerobic environment was the upregulation of fatty acid metabolism and benzoate degradation, which was linked to important changes in the bacterial membrane composition as evidenced by changes in membrane fatty acid composition and the reduction of membrane-associated demethylmenaquinone. These key metabolic pathways associated with the response of E. faecalis to oxygen may represent potential new targets to increase the susceptibility of this bacterium to bactericidal drugs.

Physicochemical and Antibacterial Properties of Novel, Premixed Calcium Silicate-Based Sealer Compared to Powder–Liquid Bioceramic Sealer

“…Thus, the present study evaluated the in vitro antibacterial activity of BR and CS against E. faecalis . Enterococcus faecalis is a Gram-positive facultative anaerobe and is able to grow in the presence or absence of oxygen [ 60 , 61 ]. E. faecalis was selected in our research because it is a microorganism and predominant bacteria found in persistent endodontic infections and in failed root canal treatment cases [ 58 , 61 ].…”

Metabolomics analysis of Pseudomonas chlororaphis JK12 algicidal activity under aerobic and micro-aerobic culture condition

“…This suggested that the bacterium could have adopted an alternative metabolic mode under oxygen limitation, leading to higher production of algicidal metabolites which far outweighed the drawback of reduced cell yield, which ultimately resulted in dramatically enhanced algicidal activity. Many studies have reported the significant effect of oxygen availability, on the biochemical properties of bacteria (McCloskey et al 2014 ; Partridge et al 2007 ; Portela et al 2014 ; Shan et al 2012 ; Trotter et al 2011 ). Aerobic respiration is conventionally the favored metabolic mode as compared to microaerobic respiration.…”

Cyclic AMP Regulates Bacterial Persistence through Repression of the Oxidative Stress Response and SOS-Dependent DNA Repair in Uropathogenic Escherichia coli

“…1d ). This included pathways for indole and glutamate metabolism ( 19 , 20 ). Indeed, these pathways have previously been linked with tolerance to antibiotics ( 9 , 21 , 22 ).…”