First report of two complete Clostridium chauvoei genome sequences and detailed in silico genome analysis

Christian Seyboldt,Mostafa Y Abdel-Glil,Heinrich Neubauer,Christiane Werckenthin,Inga Eichhorn,Lothar H Wieler,Torsten Semmler,Prasad Thomas,Antina Lübke-Becker

doi:10.1016/j.meegid.2017.07.018

Abstract

Clostridium (C.) chauvoei is a Gram-positive, spore forming, anaerobic bacterium. It causes black leg in ruminants, a typically fatal histotoxic myonecrosis. High quality circular genome sequences were generated for the C. chauvoei type strain DSM 7528T (ATCC 10092T) and a field strain 12S0467 isolated in Germany. The origin of replication (oriC) was comparable to that of Bacillus subtilis in structure with two regions containing DnaA boxes. Similar prophages were identified in the genomes of both C. chauvoei strains which also harbored hemolysin and bacterial spore formation genes. A CRISPR type I-B system with limited variations in the repeat number was identified. Sporulation and germination process related genes were homologous to that of the Clostridia cluster I group but novel variations for regulatory genes were identified indicative for strain specific control of regulatory events. Phylogenomics showed a higher relatedness to C. septicum than to other so far sequenced genomes of species belonging to the genus Clostridium. Comparative genome analysis of three C. chauvoei circular genome sequences revealed the presence of few inversions and translocations in locally collinear blocks (LCBs). The species genome also shows a large number of genes involved in proteolysis, genes for glycosyl hydrolases and metal iron transportation genes which are presumably involved in virulence and survival in the host. Three conserved flagellar genes (fliC) were identified in each of the circular genomes. In conclusion this is the first comparative analysis of circular genomes for the species C. chauvoei, enabling insights into genome composition and virulence factor variation.

Highlights

Blackleg is an economically important disease with high mortality that affects cattle, sheep and other animals
High quality circular genome sequences were generated for the C. chauvoei type strain DSM 7528T (ATCC 10092T) and a field strain 12S0467 isolated in Germany
Phylogenomics showed a higher relatedness to C. septicum than to other so far sequenced genomes of species belonging to the genus Clostridium

Summary

Introduction

Blackleg (black quarter, quarter evil, Rauschbrand, charbon symptomatique) is an economically important disease with high mortality that affects cattle, sheep and other animals. The disease is caused by Clostridium (C.) chauvoei, a Gram-positive, motile, spore producing anaerobic bacterium. ⁎ Corresponding author at: Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Bacterial Infections and Zoonoses, Naumburger Str. 96a, 07743 Jena, Germany. P. Thomas et al / Infection, Genetics and Evolution 54 (2017) 287–298 phylogenetic clusters with cluster I forming the core group of the genus (Collins et al, 1994). More than half of the pathogenic species are members of this cluster including those considered the major pathogenic agents, i.e. C_botulinum, C. haemolyticum, C. novyi, C. perfringens, C. tetani, C. septicum and C. chauvoei (Stackebrandt et al, 1999). The phylogenetic positioning of C. chauvoei based on 16 s rDNA sequence shows this pathogen close to C. septicum (Kuhnert et al, 1996)

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