The local enhancement of infection by exogenous ferric iron, as ferric ammonium citrate, and by ferrous iron as guinea-pig haemoglobin, was assessed in studies with 55 strains of bacteria injected into the skin of guinea-pigs. The test organisms included spp., spp., and . Four strains of spp. were tested with haemoglobin only. As previously reported with other strains, enhancement of infection by members of a given species by ferric iron was variable; in this study infection with only 11 of 59 strains was enhanced. Haemoglobin either of equal or lesser iron content was a more potent enhancer, affecting 27 of the 59 strains. The enhancement ranged from two-fold to 80-fold, the higher figures on the whole being characteristic of haemoglobin enhancement. Some few instances of depression by both haemoglobin and ferric ammonium citrate were noted. A few tests were made with systemic haemoglobin but the concentrations attainable were largely ineffective. Enhancement of infection did not appear to be related to the capacity of a strain to lyse or digest host red blood cells.

In so far as guinea-pigs, whose antibacterial defences are lowered by ferric or ferrous iron, represent human subjects at risk of infection because of clinical circumstances characterised by excess of available iron—either exogenous or as a result of haemolysis—our results with organisms of a kind commonly associated with infection in hospitals suggest that only a small proportion of environmental bacteria can take advantage of any decreased resistance associated with iron excess.


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  1. Bornside G. H., Cohn L. 1968; Hemoglobin as a bacterial virulence-enhancing factor in fluids produced in strangulation intestinal obstruction.. The American Surgeon 34:63–67
    [Google Scholar]
  2. Bullen J. J., Rogers H. J. 1968; Effect of haemoglobin on experimental infections with Pasteurella septica and Escherichia coli. Nature 217:86
    [Google Scholar]
  3. Lightbown J. W., Sulitzeanu D. 1957; The assay of penicillin in blood-serum using Sarcina lutea. Bulletin of the World Health Organization 17:553–567
    [Google Scholar]
  4. Miles A. A., Khimji P. L. 1975; Enterobacterial chelators of iron: their occurrence, detection and relation to pathogenicity.. Journal of Medical Microbiology 8:477–490
    [Google Scholar]
  5. Miles A. A., Khimji P. L., Maskell J. 1979; The variable response of bacteria to excess ferric iron in host tissues.. Journal of Medical Microbiology 12:17–28
    [Google Scholar]
  6. Miles A. A., Pillow J., Khimji P. L. 1976; The action of iron on local Klebsiella infection of the skin of the guinea-pig and its relation to the decisive period in primary infective lesions.. British Journal of Experimental Pathology 57:217–242
    [Google Scholar]

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