title: Effect of subinhibitory concentrations of cephalosporins on surface properties and siderophore production in iron-depleted Klebsiella pneumoniae.
abstract: Subinhibitory MICs (sub-MICs) of several cephalosporins significantly reduced the enterochelin production of Klebsiella pneumoniae 327 grown under iron-depleted conditions and also reduced capsule formation regardless of iron availability. The surface hydrophobicity of K. pneumoniae 327 increased significantly when the bacteria were grown in either iron-sufficient or iron-depleted media in the presence of sub-MICs of all the cephalosporins used in this study. Antisera raised against a non-encapsulated K. pneumoniae strain caused rapid agglutination of K. pneumoniae 327 grown in the presence of sub-MICs of the cephalosporins but no agglutination of the same strain grown in drug-free media. The results indicated that the cephalosporins reduced enterochelin production and also capsule formation to the extent that noncapsular surface antigens were exposed, with possible significant consequences in vivo.
authors.forename: J L
authors.initials: JL
authors.lastname: Kadurugamuwa
authors.forename: H
authors.initials: H
authors.lastname: Anwar
authors.forename: M R
authors.initials: MR
authors.lastname: Brown
authors.forename: O
authors.initials: O
authors.lastname: Zak
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002511:Cephalosporins / Q000494:pharmacology*; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D004758:Enterobactin / Q000096:biosynthesis*; D007501:Iron / Q000378:metabolism*; D007502:Iron Chelating Agents / Q000096:biosynthesis*; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D012694:Serine / Q000031:analogs & derivatives*; D017262:Siderophores; D013499:Surface Properties; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D002511:Cephalosporins; D003470:Culture Media; D007502:Iron Chelating Agents; D017262:Siderophores; D004758:Enterobactin; D012694:Serine; D007501:Iron