title: Novel aerobactin receptor in Klebsiella pneumoniae.
abstract: Several Klebsiella pneumoniae strains which produced enterochelin but not aerobactin were nevertheless sensitive to cloacin DF13. In contrast, a strain of serotype K1:O1 which produced both siderophores was cloacin-resistant. Loss by mutation of the O1 but not K1 antigen rendered this strain cloacin-sensitive, indicating that the O1 antigen prevented access of cloacin to the cloacin/aerobactin receptor. Unlike the K1:O1 strain, the aerobactin-negative strains failed to hybridize in a colony blot assay with an aerobactin receptor gene probe prepared from pColV-K30. However, antisera raised against the 74 kDa pColV-K30 aerobactin receptor cross-reacted with a 76 kDa outer-membrane protein in each K. pneumoniae strain. In addition to the 76 kDa protein, the K1:O1 strain also produced a strongly cross-reacting 74 kDa protein. To determine whether these aerobactin-negative strains could use aerobactin, mutants unable to synthesize siderophores were isolated. Aerobactin promoted the growth of these mutants in iron-deficient media. The evidence presented suggests that some K. pneumoniae strains produce an aerobactin iron-uptake system without apparent production of aerobactin and which is probably based on a 76 kDa receptor, the gene for which does not hybridize with aerobactin receptor gene encoded on pColV-K30.
authors.affiliation: Department of Pharmaceutical Sciences, University of Nottingham, UK.
authors.forename: P
authors.initials: P
authors.lastname: Williams
authors.forename: M A
authors.initials: MA
authors.lastname: Smith
authors.forename: P
authors.initials: P
authors.lastname: Stevenson
authors.forename: E
authors.initials: E
authors.lastname: Griffiths
authors.forename: J M
authors.initials: JM
authors.lastname: Tomas
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D002989:Cloacin / Q000494:pharmacology; D003429:Cross Reactions; D004591:Electrophoresis, Polyacrylamide Gel; D004758:Enterobactin / Q000378:metabolism; D005798:Genes, Bacterial; D006877:Hydroxamic Acids / Q000378:metabolism; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D008970:Molecular Weight; D011971:Receptors, Immunologic / Q000378:metabolism*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D006877:Hydroxamic Acids; D011971:Receptors, Immunologic; C034506:aerobactin receptor; C031819:aerobactin; D004758:Enterobactin; D002989:Cloacin