Complete genome sequence of Clostridium perfringens , an anaerobic flesh-eater

Abstract

Clostridium perfringens is a Gram-positive anaerobic spore-forming bacterium that causes life-threatening gas gangrene and mild enterotoxaemia in humans, although it colonizes as normal intestinal flora of humans and animals. The organism is known to produce a variety of toxins and enzymes that are responsible for the severe myonecrotic lesions. Here we report the complete 3,031,430-bp sequence of C. perfringens strain 13 that comprises 2,660 protein coding regions and 10 rRNA genes, showing pronounced low overall G ؉ C content (28.6%). The genome contains typical anaerobic fermentation enzymes leading to gas production but no enzymes for the tricarboxylic acid cycle or respiratory chain. Various saccharolytic enzymes were found, but many enzymes for amino acid biosynthesis were lacking in the genome. Twenty genes were newly identified as putative virulence factors of C. perfringens, and we found a total of five hyaluronidase genes that will also contribute to virulence. The genome analysis also proved an efficient method for finding four members of the two-component VirR͞VirS regulon that coordinately regulates the pathogenicity of C. perfringens. Clearly, C. perfringens obtains various essential materials from the host by producing several degradative enzymes and toxins, resulting in massive destruction of the host tissues.

The Spatial Organization of the VirR Boxes Is Critical for VirR-Mediated Expression of the Perfringolysin O Gene, pfoA , from Clostridium perfringens

“…An alignment of the various VirR boxes showed that the sequences of these boxes were similar, but not identical (38) (Fig. 3A).…”

“…When other VirR boxes that have been detected in the C. perfringens genome (38) were inserted upstream of pfoA, in lieu of the pfoA VirR boxes, we found that they conferred different levels of perfringolysin O activity in the reporter system. The results suggested that differences in the in vitro binding abilities were not a likely cause of the different levels of transcriptional activation that were observed.…”

“…By performing in vitro binding studies, we showed that VirR binds to each of these repeats independently, i.e., binding to the VirR boxes is not cooperative (11). The identification of the VirR boxes (11), in conjunction with the sequencing of the C. perfringens strain 13 genome (38), has led to the identification of putative VirRbinding sites upstream of other genes (38), two of which have been demonstrated to be regulated by VirR (40,41).…”

Triclocarban Influences Antibiotic Resistance and Alters Anaerobic Digester Microbial Community Structure

“…(46) The Bacteria classes Actinobacteria and Clostridia were enriched in the inhibited reactors as well; both of these classes contain pathogenic bacterial strains which may have antibiotic resistance, and the Actinobacteria class contains many acid tolerant bacteria. (47,48) …”

Efficient gene transfer and targeted mutagenesis in Fusobacterium nucleatum

“…Another feature that could contribute to the efficiency of pHS30 may relate to the use of the resistance determinant catP, isolated originally from a strain of C. perfringens (1). C. perfringens and F. nucleatum are characterized by strikingly low genomic GC content, at 29 and 27%, respectively (22,35). Differences in the promoters or codon bias may affect expression of the catP gene versus the erm determinants (32), thereby influencing the recovery of transformants.…”