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Open Access Research article

Corynebacterium ulcerans 0102 carries the gene encoding diphtheria toxin on a prophage different from the C. diphtheriae NCTC 13129 prophage

Tsuyoshi Sekizuka1, Akihiko Yamamoto2, Takako Komiya2, Tsuyoshi Kenri2, Fumihiko Takeuchi1, Keigo Shibayama2, Motohide Takahashi23, Makoto Kuroda1 and Masaaki Iwaki2*

Author Affiliations

1 Laboratory of Bacterial Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan

2 Department of Bacteriology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama-shi, Tokyo, 208-0011, Japan

3 Present address: Pharmaceutical and Medical Devices Agency, Tokyo, Japan

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BMC Microbiology 2012, 12:72  doi:10.1186/1471-2180-12-72

Published: 14 May 2012

Abstract

Background

Corynebacterium ulcerans can cause a diphtheria-like illness, especially when the bacterium is lysogenized with a tox gene-carrying bacteriophage that produces diphtheria toxin. Acquisition of toxigenicity upon phage lysogenization is a common feature of C. ulcerans and C. diphtheriae. However, because of a lack of C. ulcerans genome information, a detailed comparison of prophages has not been possible between these two clinically important and closely related bacterial species.

Results

We determined the whole genome sequence of the toxigenic C. ulcerans 0102 isolated in Japan. The genomic sequence showed a striking similarity with that of Corynebacterium pseudotuberculosis and, to a lesser extent, with that of C. diphtheriae. The 0102 genome contained three distinct prophages. One of these, Ī¦CULC0102-I, was a tox-positive prophage containing genes in the same structural order as for tox-positive C. diphtheriae prophages. However, the primary structures of the individual genes involved in the phage machinery showed little homology between the two counterparts.

Conclusion

Taken together, these results suggest that the tox-positive prophage in this strain of C. ulcerans has a distinct origin from that of C. diphtheriae NCTC 13129.

Keywords:
Bacteriophage; Toxin gene; Horizontal gene transfer; Diphtheria; Zoonosis