Classification and Identification of Chlamydia, Rickettsia, and Related Bacteria

摘要

Genera included in the orders Chlamydiales and Rickettsiales in section 9 ofBergey's Manual of Systematic Bacteriology (19) were grouped together largely because of their smallness and usual intimate association with eukaryotic cells and because of the similarity of techniques required for their identification and study. Table 1 summarizes some of the properties of the major species and groups of clinical importance. The rapid application of molecular methods for their classification and identification, the continuous addition of new species, and the alterations in generic assignments of species addressed in the fifth edition of this Manual (36) have continued apace. Only recently have the phylogenetic relationships among most of the principal agents of human and veterinary; disease in these orders been fully established by determination of sequences of DNA coding for 16S rRNA (rDNA) (8, 17, 22, 23). General molecular methods such as DNA sequencing and restriction fragment length polymorphism (RFLP) analysis by PCR-amplified genus-specific genes are also being rapidly applied to the identification and classification of both new species and serotypes (4-6, 8, 12, 14, 16, 18, 26). However, investigations of biochemical phenonpic traits amono these species, with the notable exception of the Bartonella (Rochalimaea) species, which can be grown on axenic media (9, 37), have been quite limited because of the difficulties involved in studying obligately intracellular bacteria. Moreover, preparation and availability of specific monoclonal or polyclonal antibody reagents have lagged greatly behind the addition of new species and serotypes (with the notable exception of Chlamydia and some Rickettsia species), largely because relatively few laboratories have the specialized containment facilities or resources required for investigating many of these agents.