Taxonomy of spirochetes

The taxonomy of spirochetes has improved considerably over the last few yea rs. Even non-cultivable spirochetes have been classified and identified and highly discriminating analytical methods have been used to distinguish the se unique organisms. The present article reviews major characteristics and techniques that have been applied in recent molecular taxonomy and chemotax onomy of spirochetes. These comprise cellular lipids, carbohydrates, peptid oglycan, enzymes, cell proteins, cytoplasmic fibrils, metabolites, genome s ize, structure and base composition, restriction endonuclease analysis, res triction fragment length polymorphism, multilocus enzyme electrophoresis, p ulsed-field gel electrophoresis, DNA-DNA hybridization, arbitrarily primed polymerase chain reaction/randomly amplified polymorphic DNA fingerprinting , ribosomal (r) RNA cataloguing and sequencing, characterization of interge nic spacer regions of rRNA genes, ospA, lipoprotein and flagellin gene sequ encing, and rRNA gene organization. Characteristics and techniques such as those listed above have contributed to the recognition of new spirochetal g enera and species and have made spirochetal taxonomy polyphasic. Despite th ese improvements, significant reservoirs of hitherto unrecognized. spiroche tal diversity probably still exist. (C) 2000 Academic Press.