Bacterial virulence: can we draw the line?

The molecular approach to microbial pathogenesis has resulted in an impress ive amount of data on bacterial virulence genes. Bacterial genome sequences rapidly add candidate virulence genes to electronic databases. The interpr etation of this overwhelming information is obscured because every gene inv olved in pathogenicity is called a virulence gene, regardless of its functi on in the complex process of virulence. This review summarizes the changing concept of bacterial virulence and the detection and identification strate gies followed to recognize virulence genes. A refined definition of virulen ce genes is proposed in which the function of the gene in the virulence pro cess is incorporated. We propose to include the life-style of bacteria in t he assessment of their putative virulence genes. A universal nomenclature i n analogy to the EC enzyme numbering system is proposed. These recommendati ons would lead to a better insight into bacterial virulence and a more prec ise annotation of(putative) virulence genes, which would enable more effici ent use of electronic databases. (C) 2001 Federation of European Microbiolo gical Societies. Published by Elsevier Science B.V. All rights reserved.