Spirochetes
1990; Elsevier BV; Linguagem: Inglês
10.1016/b978-0-12-161775-2.50009-8
Autores Tópico(s)Veterinary medicine and infectious diseases
ResumoSpirochetes are classified as bacteria in the order Spirochaetales and contain two families—the Spirochaetaceae and the Leptospiraceae. The Spirochaetaceae family includes four genera: Spirochaeta, Cristispira, Treponema, and Borrelia. Two of these genera—Spirochaeta and Cristispira—are considered free-living and commensal, respectively. The other three genera—Treponema, Borrelia, and Leptospira—contain pathogenic species. Spirochetes are slender, spiral in shape, round on cross section, and multiply by transverse fission. Their movement is active and accomplished by spinning and flexing about the long axis. They are found in water, soil, decaying organic matter, plants, animals, and humans. These microorganisms are relatively inactive biochemically, and their identification is based on staining reactions, growth requirements, morphology, pathogenicity, and serology. This chapter reviews the distinguishing characteristics of the three pathogenic genera—Leptospira, Treponema, and Borrelia. They are gram-negative bacteria but are observed best by darkfield or phase microscopy or by staining with silver impregnation or Giemsa stain. However, only Borrelia stains with aniline dyes.
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