IRON AND OUTER-MEMBRANE PROTEINS IN THE SUSCEPTIBILITY OF NEISSERIA-MENINGITIDIS TO HUMAN SERUM

The proportion of carrier-isolated Neisseria meningitidis strains sensitive to human serum (37.2%) was found to be significantly higher than that of case-isolated ones (4.1%), although the difference is too low to consider serum-resistance responsible for invasion in this microorganism. Serum-susceptibility was not related to the existence of specific outer membrane proteins, as is the case in N. gonorrhoeae. Iron restriction induced iron-regulated outer membrane proteins in each strain (but not the same proteins in all strains) but without any detectable effect on serum-susceptibility. Iron excess was also unable to induce changes in the susceptibility of N. meningitidis to human serum. © 1990 Federation of European Microbiological Societies.