Simple method for the isolation of anaerobic oral vibrios.

Anaerobic vibrios are among the more difficult microorganisms to isolate among the oral commensal flora. They comprise a heterogeneous group of motile, nonsporulating, gram-negative, strictly anaerobic rods. A tentative classification based largely on the studies of Macdonald (1953) separates these bacteria into four species, only one of which is considered as properly belonging in the genus Vibrio (Rosebury and Sonnenwirth, 1958). The poor growth of these bacteria on the surface of semisolid media, despite their abundance in the inocula, is generally considered to result from exacting requirements with respect to carbon dioxide tension, anaerobiosis, and complex nutritional factors. In the course of other work with oral bacteria, it was observed that anaerobic vibrios grew luxuriantly in trypticase soy broth and that this medium could be used for their isolation.