Bergey's Manual® of Systematic Bacteriology: The Proteobacteria (Part C)

Since publication of the first edition of Bergey’s Manual of Systematic Bacteriology, it has become recognized throughout the world as the principal monographic work in the field of prokaryotic biology. Like a dictionary to a writer, the Manual is usually the first reference that a microbiologist consults when questions arise regarding the characteristics of an unfamiliar species or an unknown strain that bears some similarity to a more familiar one. While the first edition has served the community well for many years, it has become outdated. As a result, the editorial board of Bergey’s Manual Trust, in collaboration with more than 500 of the world’s leading authorities in prokaryotic systematics, is in the process of revising Bergey’s Manual of Systematic Bacteriology so that it reflects current thinking and advances in the field.

Background

Rapid advances in DNA sequencing technology have led to a major change in the way that prokaryotes are classified. Sequence analysis of highly conserved regions of the bacterial genome, such as the small subunit rRNA gene, now provide us with a universal method of estimating the evolutionary relationships among all organisms. Such gene-based phylogenetic classifications have led to many new discoveries about prokaryotes that were not reflected in the classification used in the first edition of the Manual. We now know that the prokaryotes fall into two broad domains: the Archaea and the Bacteria. Whereas the Archaea were once thought of as the more primitive of the prokaryotic lineages, we now realize that they are more closely related to the eukaryotes than to the Bacteria by this measure. We have come to realize that many taxa based on shared phenotypic features may be quite distinct from one another based on phylogenetic evidence. The Chromatium, a genus of anoxygenic photosynthetic bacteria are more closely related to E. coli than to some other lineages of anoxygenic photosynthetic bacteria; Mycoplasma and other cell-wall defi