摘要：SummaryEnterobacter cloacaecomplex species are involved in infections among critically ill patients. After a recentE.cloacaeoutbreak of fulminant neonatal septic shock, we conducted a study to determine whether septic shock severity and its lethal consequence are related to structural features of the endotoxin (lipopolysaccharide [LPS]) of the strains isolated from hospitalized infants and more specifically its lipid A region. It appeared that the LPSs are very heterogeneous, carrying fifteen different molecular species of lipid A. The virulence was correlated with a structural feature identified by matrix-assisted laser desorption ionization–time of flight mass spectrometry and gas chromatography coupled with mass spectrometry: the presence of 2-hydroxymyristic acid as a secondary substituent in lipid A. This is the first published evidence linking LPS structural moiety to neonatal sepsis outcome and opens the possibility of using this fatty acid marker as a detection tool for high-risk patients, which could help reduce their mortality.Graphical abstractDisplay OmittedHighlights•Fifteen different molecular species of lipid A is found inE. cloacaecomplex•2-Hydroxymyristate moiety on Lipid A is a virulence marker of theE. cloacaecomplex•Presence of 2-hydroxymyristate is associated with mortality in neonatal sepsisMolecular biology; Immunology; Microbiology
