Anti-C. diphtheriae Diphtheria Toxin Polyclonal antibody[FITC]

Corynebacterium diphtheriae is typically recognized as the a etiological agent of diphtheria, a toxaemic infection of the respiratory tract; however, both non-toxigenic and toxigenic strains are increasingly isolated from cases of invasive infections. The molecular mechanisms responsible for bacterial colonization and dissemination to host tissues remain only partially understood. In this report, we investigated the role of DIP2093, described as a putative adhesin of the serine-aspartate repeat (Sdr) protein family in host-pathogen interactions of C. diphtheriae wild-type strain NCTC13129. Compared to the parental strain, a DIP2093 mutant RN generated in this study was attenuated in its ability to bind to type I collagen, to adhere to and invade epithelial cells, as well as to survive within macrophages. Furthermore, DIP2093 mutant strain RN had a less detrimental impact on the viability of Caenorhabditis elegans as well as in the clinical severity of arthritis in mice. In conclusion, DIP2093 functions as a microbial surface component recognizing adhesive matrix molecules, and may be included among the factors that contribute to the pathogenicity of C. diphtheriae strains, independently of toxin production.

We have constructed defined deletions in the hmuO gene from Corynebacterium diphtheriae and Corynebacterium ulcerans and show that the C. ulcerans hmuO mutation results in a significant reduction in hemoglobin-iron utilization, whereas in C. diphtheriae strains, deletion of hmuO caused no or only partial reduction in the utilization of heme as an iron source. We also show that expression from the C. ulcerans hmuO promoter exhibits minimal regulation by iron and heme whereas transcription from the C. diphtheriae hmuO promoter shows both significant iron repression and heme-dependent activation. These findings indicate that variability in HmuO function and expression exists among Corynebacterium species.