Etymologia: Nocardia

Nocardia [no-kahr¢ e-əm]

The genus Nocardia is named in honor of Edmond Isidore Etienne Nocard (1850–1903), a French veterinarian and microbiologist who discovered the bacteria in 1888 from a bovine farcy case. He named this filamentous, branching bacteria Streptothrix farcinica (Greek streptós- “twisted” and thrix “hair”). Farcy (old French farcin), is a form of cutaneous glanders, characterized by superficial lymph node swelling and ulcerating nodule formation under the skin (Late Latin farcīminum “glanders,” from Latin farcīmen “a sausage,” from farcīre “to stuff”).

One year later, Trevisan characterized and termed the bacteria Nocardia farcinica (Figure), creating the genus Nocardia. In 1890, Eppinger isolated a similar organism from a brain abscess and called it Cladothrix asteroides (Greek kládos- “branch” and -thrix “hair”) because of its star-shaped colonies (Greek asteroeidēs “starlike”). Blanchard renamed the organism Nocardia asteriodes in 1896. Additional taxonomic work in 1962 resulted in Nocardia asteroides replacing Nocardia farcinica as the type species for the genus Nocardia.

Figure.

Twisted hair bacteria (Nocardia spp.) described by Edmond Nocard, from a bronchial alveolar lavage sample. Nocardiosis is an opportunistic infection, commonly associated with pulmonary disease. Nocardia are partially acid-fast, filamentous, branching bacilli (modified Kinyoun acid-fast stain using weak acid [0.5% sulfuric acid] for decolorization and methylene blue counterstain, original magnification x1,000.) Photograph courtesy of the author.