Detection of selected fastidious bacteria.

The intent of this article is to describe the optimal methods for culture recovery of 7 fastidious bacteria: Legionella species, Brucella species, Francisella tularensis, Leptospira species, Borrelia burgdorferi, Bartonella species, and Bordetella species. These organisms share much in common beyond the fact that their genus names all end in the letter "a." Culture recovery of these organisms, even from adequate clinical specimens, is logistically demanding, often costly, and lacking in both timeliness and sensitivity. In addition, there is generally no need to recover culture isolates on which to perform antimicrobial susceptibility tests because these 7 bacteria are nearly uniformly susceptible to specific, clinically useful antimicrobial agents and because, for some of them, susceptibility tests of proven reliability have not yet been devised. Perhaps for these reasons, alternative, more rapid, direct diagnostic approaches have been developed that are based on either immunochemical or nucleic-acid detection methods. These methods have generally served to supplant culture as a primary diagnostic modality. Situations exist, however, in which culture may be desirable, if not necessary, to establish a definitive diagnosis of infection with these 7 organisms. This review attempts to summarize how best to proceed in those cases.