The phylum spirochaetaceae

Abstract

Spirochaetaceae is a family of spirochetes that cause syphilis, Lyme disease, epidemic and endemic relapsing fever, leptospirosis, swine dysentery, and periodontal disease. The spirochetes are presently classified as members of class Spirochaetes in the order Spirochaetales and are divided into three major phylogenetic groupings or families. The first family, Spirochaetaceae, contains species in the genera Borrelia, Brevinema, Cristispira, Spirochaeta, Spironema, and Treponema. The second family, Brachyspiraceae, contains the genus Brachyspira (Serpulina). The third family, Leptospiraceae, contains species of the genera Leptonema and Leptospira. One of the unique features of spirochetes is motility mediated by axial flagella with a rapid drifting rotation. The DNA of the Spirochaeta species contains guanine (G) + cytosine (C) ranging from 51 % to 65 mol %. The presence of several linear plasmids seems to cause the segmentation of Borrelia DNA into several linear pieces. This has led to the suggestion that the relatively small linear chromosome and the linear plasmids actually are minichromosomes. Various molecular and immunological detection methods have been developed for detection and identification of spirochetes.