We present 2 case reports in the United States and investigations of diphtheria-like illness caused by toxigenic Corynebacterium ulcerans. A fatal case occurred in a 75-year-old male Washington resident who was treated with clindamycin but did not receive equine diphtheria antitoxin. A second, nonfatal case occurred in a 66-year-old female Tennessee resident who received erythromycin and diphtheria antitoxin.
Both case patients and close human and animal contacts were investigated by their respective state health departments.
C. ulcerans isolated from the patient who died was resistant to erythromycin and clindamycin. For both isolates, conventional polymerase chain reaction results were positive for A and B subunits of diphtheria toxin gene tox, and modified Elek tests confirmed toxin production. The source of infection remained undetermined for both cases. Neither patient was up-to-date with diphtheria toxoid vaccination.
These case reports highlight the importance of early treatment with diphtheria antitoxin, the selection of effective antimicrobial agents, and prevention through up-to-date vaccination.
"Human C. ulcerans infections are caused by ingestion of untreated milk (Bostock et al., 1984) or close contact with animals (Hatanaka et al., 2003; Komiya et al., 2010; Tiwari et al., 2008). Our patient had six pet cats; although these animals were examined, C. ulcerans strains were not detected. "
[Show abstract][Hide abstract] ABSTRACT: Corynebacterium ulcerans is attracting attention as an emerging zoonosis that causes lymphadenitis, dermatitis, and respiratory infections. We report here the first case of subcutaneous abscess formation in the upper extremity due to toxigenic C. ulcerans in Japan. Awareness of the fact that C. ulcerans can cause a subcutaneous, elastic-hard, less-mobile mass with heat, redness, and pain in the extremities is important for differential diagnosis.
Journal of Medical Microbiology 12/2012; 62(Pt_3). DOI:10.1099/jmm.0.051458-0 · 2.25 Impact Factor
"This observation has been explained by the fact that C. ulcerans may harbor lysogenic β-corynephages coding for the diphtheria toxin, which is responsible for the systemic symptoms caused by C. diphtheriae . Respiratory diphtheria-like illnesses caused by toxigenic C. ulcerans strains are increasingly reported from various industrialized countries  and became more common than C. diphtheriae infections in the United Kingdom . Human infections with toxigenic C. ulcerans can be fatal in unvaccinated patients and usually occur in adults, who consumed raw milk [7,8] or had close contact with domestic animals . "
[Show abstract][Hide abstract] ABSTRACT: Corynebacterium ulcerans has been detected as a commensal in domestic and wild animals that may serve as reservoirs for zoonotic infections. During the last decade, the frequency and severity of human infections associated with C. ulcerans appear to be increasing in various countries. As the knowledge of genes contributing to the virulence of this bacterium was very limited, the complete genome sequences of two C. ulcerans strains detected in the metropolitan area of Rio de Janeiro were determined and characterized by comparative genomics: C. ulcerans 809 was initially isolated from an elderly woman with fatal pulmonary infection and C. ulcerans BR-AD22 was recovered from a nasal sample of an asymptomatic dog.
The circular chromosome of C. ulcerans 809 has a total size of 2,502,095 bp and encodes 2,182 predicted proteins, whereas the genome of C. ulcerans BR-AD22 is 104,279 bp larger and comprises 2,338 protein-coding regions. The minor difference in size of the two genomes is mainly caused by additional prophage-like elements in the C. ulcerans BR-AD22 chromosome. Both genomes show a highly similar order of orthologous coding regions; and both strains share a common set of 2,076 genes, demonstrating their very close relationship. A screening for prominent virulence factors revealed the presence of phospholipase D (Pld), neuraminidase H (NanH), endoglycosidase E (EndoE), and subunits of adhesive pili of the SpaDEF type that are encoded in both C. ulcerans genomes. The rbp gene coding for a putative ribosome-binding protein with striking structural similarity to Shiga-like toxins was additionally detected in the genome of the human isolate C. ulcerans 809.
The molecular data deduced from the complete genome sequences provides considerable knowledge of virulence factors in C. ulcerans that is increasingly recognized as an emerging pathogen. This bacterium is apparently equipped with a broad and varying set of virulence factors, including a novel type of a ribosome-binding protein. Whether the respective protein contributes to the severity of human infections (and a fatal outcome) remains to be elucidated by genetic experiments with defined bacterial mutants and host model systems.
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