Journal Article

Comprehensive analysis of phospholipids and glycolipids in the opportunistic pathogen Enterococcus faecalis

Cazenave-Gassiot, Amaury, Kumar, Jaspal K., Gao, Iris H., Rashid, Rafi, Kline, Kimberly A., Wenk, Markus R., Gao, Liang, Nair, Zeus J.

2017

Overview

Enterococcus faecalis is a Gram-positive, opportunistic, pathogenic bacterium that causes a significant number of antibiotic-resistant infections in hospitalized patients. The development of antibiotic resistance in hospital-associated pathogens is a formidable public health threat. In E. faecalis and other Gram-positive pathogens, correlations exist between lipid composition and antibiotic resistance. Resistance to the last-resort antibiotic daptomycin is accompanied by a decrease in phosphatidylglycerol (PG) levels, whereas multiple peptide resistance factor (MprF) converts anionic PG into cationic lysyl-PG via a trans-esterification reaction, providing resistance to cationic antimicrobial peptides. Unlike previous studies that relied on thin layer chromatography and spectrophotometry, we have performed liquid chromatography-tandem mass spectrometry (LC-MS/MS) directly on lipids extracted from E. faecalis, and quantified the phospholipids through multiple reaction monitoring (MRM). In the daptomycin-sensitive E. faecalis strain OG1RF, we have identified 17 PGs, 8 lysyl-PGs (LPGs), 23 cardiolipins (CL), 3 glycerophospho-diglucosyl-diacylglycerols (GPDGDAG), 5 diglucosyl-diacylglycerols (DGDAG), 3 diacylglycerols (DAGs), and 4 triacylglycerols (TAGs). We have quantified PG and shown that PG levels vary during growth of E. faecalis in vitro. We also show that two daptomycin-resistant (DapR) strains of E. faecalis have substantially lower levels of PG and LPG levels. Since LPG levels in these strains are lower, daptomycin resistance is likely due to the reduction in PG. This lipidome map is the first comprehensive analysis of membrane phospholipids and glycolipids in the important human pathogen E. faecalis, for which antimicrobial resistance and altered lipid homeostasis have been intimately linked.

• Publisher: Public Library of Science (PLoS),Public Library of Science
• Subject: Anti-Bacterial Agents / Anti-Bacterial Agents - pharmacology / Antibiotic resistance / Antibiotics / antiinfective agent / Antimicrobial activity / Antimicrobial agents / Bacteria / bacterial strain / Bacteriology / Biofilms / Biology and Life Sciences / Biosynthesis / Biotransformation / cardiolipin / Cardiolipins / Cardiolipins - classification / Cardiolipins - isolation & purification / Cardiolipins - metabolism / Cations / Cell division / chemical bond / Chromatography / Chromatography, Liquid / classification / concentration (parameters) / controlled study / daptomycin / Daptomycin - pharmacology / development and aging / diacylglycerol / diglucosyl diacylglycerol derivative / Diglycerides / Diglycerides - classification / Diglycerides - isolation & purification / Diglycerides - metabolism / drug effects / Drug resistance / Drug Resistance, Multiple, Bacterial / Drug Resistance, Multiple, Bacterial - drug effects / Drug Resistance, Multiple, Bacterial - physiology / Endocarditis / Engineering / Enterococcus faecalis / Enterococcus faecalis - drug effects / Enterococcus faecalis - growth & development / Enterococcus faecalis - metabolism / Esterification / Fatty acids / gene locus / gene mutation / glycerolipid / glycerophospho diglucosyl diacylglycerol derivative / Gram-positive bacteria / growth / Health risks / Homeostasis / in vitro study / isolation and purification / Life sciences / lipid analysis / Lipid Metabolism / Lipids / Liquid chromatography / liquid chromatography-mass spectrometry / lysine / Lysine - classification / Lysine - isolation & purification / Lysine - metabolism / lysyl phosphatidylglycerol derivative / lysylphosphatidylglycerol / Mass spectrometry / Medicine / Medicine and Health Sciences / Metabolism / Metabolomics / minimum inhibitory concentration / multidrug resistance / multiple reaction monitoring / nonhuman / Nosocomial infections / Pathogens / Peptides / phosphatidylglycerol / Phosphatidylglycerols / Phosphatidylglycerols - classification / Phosphatidylglycerols - isolation & purification / Phosphatidylglycerols - metabolism / phospholipid / Phospholipids / Public health / Q / quantitative analysis / R / Research Article / Resistance factors / Science / Scientific imaging / single nucleotide polymorphism / Spectrophotometry / Tandem Mass Spectrometry / Thin layer chromatography / triacylglycerol / Triglycerides / Triglycerides - classification / Triglycerides - isolation & purification / Triglycerides - metabolism / unclassified drug / Urinary tract diseases / Urinary tract infections / Urogenital system / whole genome sequencing / wild type