Effects of Iron Limitation on Adherence and Cell Surface Carbohydrates of Corynebacterium diphtheriae Strains

Abstract

Iron limitation may cause bacterial pathogens to grow more slowly; however, it may also stimulate these microorganisms to produce greater tissue damage, given that many virulence factors are controlled by the iron supply in the environment. The present study investigated the influence of low iron availability on the expression of proteins and surface sugar residues of two toxigenic strains of Corynebacterium diphtheriae subsp.

Diphtheria remains a threat to health in the developing world: an overview

“…diphtheriae is able to overcome host conditions, in part by producing siderophores or other iron-uptake mechanisms that allow them to express virulence factors such as toxins and enzymes. Recent results also imply regulation of adherence and slime production as part of a global response to iron-limited environmental conditions that includes derepression of genes for the synthesis of cytotoxin and siderophores and for transport of the Fe (III)-siderophore complexes (Moreira et al 2003).…”

Genomics ofActinobacteria: Tracing the Evolutionary History of an Ancient Phylum

“…Iron limitation also enhances the interaction of C. diphtheriae with erythrocytes and HEp-2 cells (303). Whether this apparent effect on host-pathogen interaction is under transcriptional control by the DtxR regulator remains to be investigated.…”

“…In addition, the release of the major virulence factor, diphtheria toxin, results in systemic intoxications, destroying the parenchyma of heart, liver, kidneys, and adrenal glands. Adherence to the host tissues plays a crucial role in extracellular mucosal pathogenesis and in the establishment of C. diphtheriae infections (286,303). The minor pilins SpaB and SpaC of the SpaA-type pilus, but not the SpaA pilus fiber itself, act as adhesins to pharyngeal epithelial cells (284).…”

Fibrinogen binds to nontoxigenic and toxigenic Corynebacterium diphtheriae strains

“…, Tonnesen et al 2000. Conditions of iron deficiency improve the ability of C. diphtheriae strains to adhere to HEp-2 cells and agglutinate human erythrocytes, partially due to changes in the glycosylation pattern of sugar residues expressed on the bacterial surface (Moreira et al 2003). Thus, the formation of the pathognomonic signs of diphtheria, along with the toxicity to the host, depends on the expression of bacterial factors of particular clones and/or environmental conditions observed during the infectious processes.…”