title: Identification and structural determination of the capsular polysaccharides from two Acinetobacter baumannii clinical isolates, MG1 and SMAL.
abstract: The structures of the capsular polysaccharides (CPSs) of the two clinical isolates Acinetobacter baumannii SMAL and MG1 were elucidated. Hot phenol/water extractions of the dry biomasses, followed by enzymatic digestions and repeated ultracentrifugations led to the isolation of polysaccharides that were negative in Western blot analysis utilizing an anti-lipid A antibody, thus proving that they were not the LPS O-antigens but CPSs. Their structures were established on the basis of NMR spectroscopy and GC-MS analyses. The A. baumannii MG1 CPS consisted of a linear aminopolysaccharide with acyl substitution heterogeneity at the N-4 amino group of QuipN4N: 4)-α-d-GlcpNAc-(1→4)-α-l-GalpNAcA-(1→3)-β-d-QuipNAc4NR-(1→ R=3-hydroxybutyrryl or acetyl. The repeating unit of the CPS produced by strain SMAL is a pentasaccharide, already reported for the O-antigen moiety from A. baumannii strain ATCC 17961:
authors.affiliation: Università di Napoli Federico II, Dipartimento di Chimica Organica e Biochimica, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126 Napoli, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Fregolino
authors.forename: Valentina
authors.initials: V
authors.lastname: Gargiulo
authors.forename: Rosa
authors.initials: R
authors.lastname: Lanzetta
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Parrilli
authors.forename: Otto
authors.initials: O
authors.lastname: Holst
authors.forename: Cristina De
authors.initials: CD
authors.lastname: Castro
mesh_terms: D000151:Acinetobacter Infections / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000737:chemistry* / Q000276:immunology; D002240:Carbohydrate Sequence; D008401:Gas Chromatography-Mass Spectrometry; D008969:Molecular Sequence Data; D019081:O Antigens / Q000737:chemistry; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D019081:O Antigens; D011135:Polysaccharides, Bacterial