genomes of the most dangerous epidemic bacteria have a virulence repertoire characterized by fewer genes but more toxin-antitoxin modules最危险的传染病的细菌的基因组有毒性曲目以更少的基因更toxin-antitoxin模块.pdfVIP

Genomes of the Most Dangerous Epidemic Bacteria Have a Virulence Repertoire Characterized by Fewer Genes but More Toxin-Antitoxin Modules Kalliopi Georgiades, Didier Raoult* ´ ´ ´ ´ ´ ´ Unite de Recherche en Maladies Infectieuses Tropicales Emergentes (URMITE), CNRS-IRD UMR 6236, Faculte de la Medecine, Universite de la Mediterranee, Marseille, France Abstract Background: We conducted a comparative genomic study based on a neutral approach to identify genome specificities associated with the virulence capacity of pathogenic bacteria. We also determined whether virulence is dictated by rules, or if it is the result of individual evolutionary histories. We systematically compared the genomes of the 12 most dangerous pandemic bacteria for humans (‘‘bad bugs’’) to their closest non-epidemic related species (‘‘controls’’). Methodology/Principal Findings: We found several significantly different features in the ‘‘bad bugs’’, one of which was a smaller genome that likely resulted from a degraded recombination and repair system. The 10 Cluster of Orthologous Group (COG) functional categories revealed a significantly smaller number of genes in the ‘‘bad bugs’’, which lacked mostly transcription, signal transduction mechanisms, cell motility, energy production and conversion, and metabolic and regulatory functions. A few genes were identified as virulence factors, including secretion system proteins. Five ‘‘bad bugs’’ showed a greater number of poly (A) tails compared to the controls, whereas an elevated number of poly (A) tails was found to be strongly correlated to a low GC% content. The ‘‘bad bugs’’ had fewer tandem repeat sequences compared to controls. Moreover, the results obtained fro