title: New aerobactin-mediated iron uptake system in a septicemia-causing strain of Enterobacter cloacae.
abstract: Unlike the great majority of the aerobactin-producing enteric bacteria documented in the literature, Enterobacter cloacae EK33, isolated from a case of human neonatal meningitis, did not show any homology at the DNA level with the prototype aerobactin system encoded by the ColV-K30 plasmid. However, both the nuclear magnetic resonance spectrum and fast-atom bombardment mass spectrometry of the siderophore purified from EK33 confirmed its identity with aerobactin. Bioassay screening of a gene library of total DNA of EK33 led to the isolation of several aerobactin-positive clones. Under conditions of iron limitation, these clones expressed in Escherichia coli a protein of 72 kilodaltons that reacted with antiserum raised against the pColV-K30 74-kilodalton aerobactin receptor, while the original E. cloacae strain synthesized an 85-kilodalton protein which also cross-reacted with the antiserum. Restriction endonuclease analysis of the cloned DNA confirmed the structural differences between the two aerobactin genetic systems.
authors.affiliation: Department of Microbiology and Immunology, Oregon Health Sciences University, Portland 97201.
authors.forename: L M
authors.initials: LM
authors.lastname: Crosa
authors.forename: M K
authors.initials: MK
authors.lastname: Wolf
authors.forename: L A
authors.initials: LA
authors.lastname: Actis
authors.forename: J
authors.initials: J
authors.lastname: Sanders-Loehr
authors.forename: J H
authors.initials: JH
authors.lastname: Crosa
mesh_terms: D003227:Conjugation, Genetic; D004754:Enterobacter / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D004755:Enterobacteriaceae / Q000378:metabolism*; D005798:Genes, Bacterial; D005838:Genotype; D006801:Humans; D006877:Hydroxamic Acids / Q000302:isolation & purification / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D010641:Phenotype; D010957:Plasmids; D018805:Sepsis / Q000382:microbiology
chemical_list: D006877:Hydroxamic Acids; C031819:aerobactin; D007501:Iron