Time to revisit polyphasic taxonomy

Abstract

Although the International Code of Nomenclature of Bacteria does not specify a working strategy, editors and reviewers of taxonomic journals commonly request a polyphasic taxonomic approach that includes phenotypic, genotypic and chemotaxonomic information for the description of novel bacterial species. Whole genome sequences provide an insight into the genetic nature of microbial species, yield new and superior tools for delineating bacterial species and for studying their phylogeny, and provide a window on an organism's metabolic potential. These new insights and tools are gradually introduced in the polyphasic taxonomic practice. The genus Burkholderia, a controversial group of bacteria with both benign and devastating characteristics, is used as an example to show that the modern practice of polyphasic taxonomy is counterproductive in light of the tremendous number of bacterial species that awaits formal description and naming. Bacterial taxonomists must urgently reconsider how to describe and name novel bacteria in the genomic era, and should consider using a full genome sequence and a minimal description of phenotypic characteristics as a basic, sufficient, cost-effective and appropriate biological identity card for a species description.