The first fatal case of Corynebacterium ulcerans infection in Japan

Abstract

Introduction.Corynebacterium ulcerans (C. ulcerans) is a zoonotic pathogen that occasionally causes diphtheria-like symptoms in humans. Cases of C. ulcerans infection have been increasing in recent years, and C. ulcerans has been recognized as an emerging pathogen. Case presentation. Here we report a case of asphyxia death due to pseudomembrane caused by diphtheria toxin (DT)-producing C. ulcerans. This is, to our knowledge, the first fatal case of C. ulcerans infection in Japan. A strain of C. ulcerans was obtained from the patient's pet cat and was confirmed to be identical to the patient's isolate by sequencing of the 16S rRNA gene and the DT gene, by pulsed-field gel electrophoresis (PFGE) and by ribotyping. In the same way, it was revealed that the isolate in this case belonged to the same molecular type as the C. ulcerans 0102 isolated from the first case in Japan in a distant prefecture 15 years earlier, in 2001. Conclusion. DT-producing C. ulcerans can be contracted from a companion animal and causes human death if the appropriate treatment is delayed. The finding indicates that this molecular type of virulent C. ulcerans is currently widespread in Japan.

Keywords: Corynebacterium ulcerans; ECMO; asphyxia; dyspnea; fatal; pseudomembrane.

Fig. 1.

Observation of the tracheal lumen using a bronchoscope (a); Tracheal bifurcation is obstructed by pseudomembrane (a-1). Pseudomembrane was sampled with forceps (a-2). The fragments of pseudomembrane sampled by forceps (b). Thoracic computed tomography (CT) shows bilateral consolidations in the lung field, pneumomediastinum around the aortic arch and obstructed tracheal lumen (c). Gram staining (×1000) of organisms isolated from the pseudomembrane sample. Bar: 10 µm (d).

Fig. 2.

The result of Western blotting analysis using anti-DT antibody (a). Sizes are indicated on the left. Lanes: 1, supernatant of fresh culture medium; 2, purified DT (0.1 ng); 3, culture supernatant of C. ulcerans; 4, culture supernatant of DT-producing Corynebacterium diphtheriae. SfiI/PFGE result of C. ulcerans strain 0102 and strains isolated in this study (b). Lanes: M, lambda marker (sizes are indicated on the left); 1, strain 0102; 2, the isolate from the patient; 3, the isolate from the patient’s pet cat. Ribotyping result of C. ulcerans strain 0102 and strains isolated in this study (c). Marker sizes of lambda Hind III are indicated on the left. Lanes: 1, strain 0102; 2, isolate from the patient; 3, isolate from the cat.