Accession Number : ADA602480


Title :   Unique Structural Modifications Are Present in the Lipopolysaccharide from Colistin-Resistant Strains of Acinetobacter baumannii


Descriptive Note : Journal article


Corporate Author : ALBANY MEDICAL COLL NY DEPT OF MICROBIOLOGY AND IMMUNOLOGY


Personal Author(s) : Pelletier, Mark R ; Casella, Leila G ; Jones, Jace W ; Adams, Mark D ; Zurawski, Daniel V ; Hazlett, Karsten R ; Doi, Yohei ; Ernst, Robert K


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a602480.pdf


Report Date : Oct 2013


Pagination or Media Count : 13


Abstract : Acinetobacter baumannii is a nosocomial opportunistic pathogen that can cause severe infections, including hospital-acquired pneumonia, wound infections, and sepsis. Multidrug-resistant (MDR) strains are prevalent, further complicating patient treatment. Due to the increase in MDR strains, the cationic antimicrobial peptide colistin has been used to treat A. baumannii infections. Colistin-resistant strains of A. baumannii with alterations to the lipid A component of lipopolysaccharide (LPS) have been reported; specifically, the lipid A structure was shown to be heptaacylated with a phosphoethanolamine (pEtN) modification present on one of the terminal phosphate residues. Using a tandem mass spectrometry platform, we provide definitive evidence that the lipid A isolated from colistin-resistant A. baumannii MAC204 LPS contains a novel structure corresponding to a diphosphoryl hepta-acylated lipid A structure with both pEtN and galactosamine (GalN) modifications. To correlate our structural studies with clinically relevant samples, we characterized colistin-susceptible and -resistant isolates obtained from patients. These results demonstrated that the clinical colistin-resistant isolate had the same pEtN and GalN modifications as those seen in the laboratory-adapted A. baumannii strain MAC204. In summary, this work has shown complete structure characterization including the accurate assignment of acylation, phosphorylation, and glycosylation of lipid A from A. baumannii, which are important for resistance to colistin.


Descriptors :   *PATHOGENIC MATERIALS , *PEPTIDES , ASSAYING , BACTERIA , CELLS(BIOLOGY) , FATTY ACIDS , LIPIDS , LIPOPOLYSACCHARIDES , LIQUID CHROMATOGRAPHY , MASS SPECTROMETRY , REPRINTS , STRAINS(BIOLOGY)


Subject Categories : Biochemistry
      Toxicology


Distribution Statement : APPROVED FOR PUBLIC RELEASE