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Subject: Iron and bacteria


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   J Clin Invest 61: 1428-40 (1978)[78194498]

The critical role of iron in host-bacterial interactions.



    S. M. Payne & R. A. Finkelstein



   The ability of potential pathogens to acquire iron in a host is an
   important determinant of both their virulence and the nature of the
   infection produced. Virulent gram-negative bacteria are capable of
   acquiring sufficient iron from the host because their virulence (for
   chick embryos) is unaffected by exogenous iron. Avirulent mutants
   which are apparently limited in their ability to acquire iron could be
   isolated from the virulent strains. The lethality of these mutants was
   significantly enhanced by exogenous iron. Reduction of the relatively
   high serum iron saturation of chick embryos (to levels more closely
   approximating those in man) by pretreatment with iron-binding proteins
   or endotoxin inhibits the lethality of some virulent bacteria. Those
   bacteria whose virulence was reduced include the Shigella, Vibrio
   cholerae and strains of Neisseria gonorrhoeae, all of which are
   nondisseminating pathogens in the normal human host. Pathogens which
   produce septicemic and disseminating infections such as Neisseria
   meningitidis, Haemophilus influenzae type B, Escherichia coli
   possessing K-1 antigen, Pseudomonas aeruginosa and Salmonella
   typhimurium and disseminating strains of N. gonorrhoeae were, in
   general, unaffected by reduced serum iron saturation. These
   disseminating bacteria appeared to produce greater quantities of
   compounds (siderophores) which stimulated microbial growth in low-iron
   media than did the nondisseminating pathogens. Thus, the gram-negative
   bacteria tested can be divided into four major classes according to
   their responses to modifications in iron levels in the chick embryo
   model and these results correlate with the nature of the infections
   which they typically produce in man.

   MeSH Terms:
     * Animal
     * Bacteria/drug effects
     * Bacteria/metabolism
     * Bacteria/pathogenicity
     * Bacterial Infections/immunology
     * Bacterial Infections/metabolism
     * Chick Embryo
     * Conalbumin/pharmacology
     * Iron/metabolism
     * Iron/pharmacology
     * Iron Chelates/metabolism
     * Support, U.S. Gov't, P.H.S.


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