Antibacterial effect of the scandium and indium complexes of enterochelin on Escherichia coli.
Enterochelin, the iron chelator produced by a number of pathogenic enterobacteria, appears to be an essential metabolite for multiplication within the host, where it transports iron from the host iron-binding proteins to the bacteria. Previous work showed that complexes of enterochelin containing either scandium (Sc3+) or indium (In3+) exerted a bacteriostatic effect on Klebsiella pneumoniae in serum, whilst the Sc3+ complex exerted a significant therapeutic effect on mice infected with K. pneumoniae. These observations have now been extended to a number of pathogenic serotypes of Escherichia coli including those carrying either the K1 antigen or the ColV plasmid. The Sc3+ and In3+ complexes each exert a bacteriostatic effect on these organisms growing in either whole serum or media containing an iron-binding protein. Evidence is presented that the Sc3+ complex may act as a competitive inhibitor of the Fe3+ complex. In contrast to their effects on K. pneumoniae, sideramines other than enterochelin fail to reverse the bacteriostatic effect of the Sc3+ complex of enterochelin in E. coli, suggesting that the complex produces a more profound derangement of metabolism in this organism. The Sc3+ complex exerts a significant therapeutic effect on E. coli infections in mice although the In3+ complex is less active.
D000818:Animals; D002614:Chelating Agents / Q000494:pharmacology*; D004758:Enterobactin / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development; D004927:Escherichia coli Infections / Q000188:drug therapy; D005260:Female; D005290:Ferric Compounds; D007204:Indium / Q000494:pharmacology*; D051379:Mice; D012538:Scandium / Q000494:pharmacology*; D012694:Serine / Q000031:analogs & derivatives*
D002614:Chelating Agents; D005290:Ferric Compounds; D007204:Indium; D004758:Enterobactin; D012694:Serine; D012538:Scandium