title: Antibacterial effect of scandium and indium complexes of enterochelin on Klebsiella pneumoniae.
abstract: A number of studies point to the conclusion that enterochelin, the iron chelator produced by a number of pathogenic enterobacteria, may be an essential metabolite for bacterial multiplication within the host. The compound removes iron from complexes with the host iron-binding proteins transferrin and lactoferrin, and the resulting ferric enterochelin is assimilated by the bacterial cell. It was reasoned that complexes of enterochelin with ions other than Fe3+ might act as antimetabolites and inhibit bacterial multiplication by interfering with the assimilation of ferric enterochelin. Enterochelin forms complexes with a number of group III and transition metal ions. The complex containing scandium exerts a bacteriostatic effect on Klebsiella pneumoniae in serum, whereas the indium complex induces a large increase in the generation time. The Fe3+ complexes of other microbial iron-transporting compounds are capable of reversing the bacteriostatic effect of the Sc3+ complex of enterochelin, suggesting that the compound acts solely by interfering with the enterochelin system of iron transport. Preliminary experiments show that the Sc3+ complex probably acts as a competitive inhibitor of ferric enterochelin. The Sc3+ complex of enterochelin exerts a therapeutic effect on intraperitoneal K. pneumoniae infections in mice similar to that obtained with kanamycin sulfate.
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004758:Enterobactin / Q000494:pharmacology*; D005260:Female; D005290:Ferric Compounds / Q000494:pharmacology; D005291:Ferrichrome / Q000494:pharmacology; D007204:Indium / Q000494:pharmacology*; D007501:Iron / Q000378:metabolism; D007710:Klebsiella Infections / Q000188:drug therapy; D007711:Klebsiella pneumoniae / Q000187:drug effects*; D008670:Metals / Q000494:pharmacology; D051379:Mice; D008826:Microbial Sensitivity Tests; D012538:Scandium / Q000494:pharmacology*; D012694:Serine / Q000031:analogs & derivatives*; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D005290:Ferric Compounds; D008670:Metals; D007204:Indium; D005291:Ferrichrome; D004758:Enterobactin; D012694:Serine; D007501:Iron; D012538:Scandium