Comparative analysis of two complete Corynebacterium ulcerans genomes and detection of candidate virulence factors
1 Institut für Genomforschung und Systembiologie, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstraße 27, D-33615 Bielefeld, Germany
2 CLIB Graduate Cluster Industrial Biotechnology, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstraße 27, D-33615 Bielefeld, Germany
3 Bioinformatics Resource Facility, Centrum für Biotechnologie, Universität Bielefeld, Universitätsstraße 25, D-33615 Bielefeld, Germany
4 Lehrstuhl für Genomforschung, Fakultät für Biologie, Universität Bielefeld, Universitätsstraße 27, D-33615 Bielefeld Germany
5 Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstraße 5, D-91058 Erlangen, Germany
6 Laboratório de Genética Celular e Molecular, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, Pampulha, Belo Horizonte, MG, Brazil
7 Instituto de Ciências Biológicas, Universidade Federal do Pará, Rua Augusto Corrêa, 01-Guamá, Belém, PA, Brazil
8 Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Av. 28 de Setembro 87, 20551-030 Rio de Janeiro, RJ, Brazil
BMC Genomics 2011, 12:383 doi:10.1186/1471-2164-12-383Published: 30 July 2011
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.