ACTION OF IRON ON LOCAL KLEBSIELLA INFECTION OF SKIN OF GUINEA-PIG AND ITS RELATION TO DECISIVE PERIOD IN PRIMARY INFECTIVE LESIONS

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  • 1 January 1976
    • journal article
    • research article
    • Vol. 57  (2) , 217-241
Abstract
The infectivity of 16 strains of Klebsiella spp. and its modification by systemic and local Fe3+ were tested in the skin of the guinea-pig. The in vivo proliferation of 11 strains was enhanced in varying degrees by Fe3+ (E+ strains); 5 strains (Eo) were not enhanceable even by large doses of Fe3+. Of 10 strains examined in detail, 6 were E+ and 4 were Eo. Guinea-pig and human sera were consistently bacteriostatic for E+ strains and bactericidal for Eo strains. Fe3+ and microbial Fe chelators abolished the bacteriostasis of E+ strains but did not affect the lethal effect on Eo strains. Both effects were diminished by heating the sera to 56.degree. for 30 min and by the anticomplementary substance Liquoid; neither appeared to be due to specific antibody. Virulence, as measured in the skin and by i.v. injection, was roughly associated with degree of enhanceability by Fe, the Eo strains being among the least virulent. The volume of plasma exudate entering the skin during the first 5 h was sufficient to kill a large proportion of the infecting doses of Eo strains and to inhibit the growth of infecting doses of E+ strains. Enhancement of the latter by Fe3+ is predominantly the result of inhibition of the non-specific bacteriostasis exerted by the extravascular plasma. Lesions by E+ strains aged .gtoreq. 4 h are insusceptible to systemic Fe3+ and only moderately susceptible to large doses of local Fe3+. The insusceptibility appears to be due to segregation of the infecting bacilli within exudate leukocytes. Klebsiella infections accordingly provide another example of an initial decisive period o acion of the antibacterial defences (in this case non-specific and humoral) which cease to be locally effective after the 1st few hours. Besides enhancing lesions due to E+ strains, systemic Fe3+ has an opposite, apparently anti-inflammatory action on Klebsiella lesions, slightly decreasing their size; this was evident with all the strains tested, whether dead or alive, but not in E+ lesions in circumstances when they were susceptible to enhancement by the Fe3+.