Sequence-Based Identification of Legionella

Legionella strains are considered biologically inert with respect to traditional identification schemes. Various phenotypic alternatives have been attempted but all have lacked resolution as additional species have been added to what is proving to be a large genus. Only sequence-based schemes have the required resolution to confidently speciate or recognize potentially novel strains. The mip gene target is the most comprehensive currently available, with the added advantage of a Web-based analysis tool. Other gene targets are available for most if not all species, the best of which target 16S rRNA, rpoB, rnpB , or proA genes. One or several of these should be used to confirm important strains or clarify apparent novelness. The increased resolution of these sequence-based schemes has recognized many new species, and many more remain to be characterized. I provide a mip analysis of 44 such strains along with the recognized species, and a SplitsTree network analysis of recognized species and 20 novel strains for which sequence for the five targets is available.