Veillonella

A genus of nonmotile, non–spore-forming, anaerobic bacteria (family Veillonellaceae) containing small (0.3–0.5 μm in diameter), Gram-negative cocci which occur as diplococci short chains and in masses. Carbon dioxide is required for growth, and carbohydrates are not fermented. These organisms are parasitic in the mouth and the intestinal and respiratory tracts of humans and other animals; they produce serologically specific endotoxins (lipopolysaccharides) that induce pyrogenicity and the Schwarzman phenomenon in rabbits; in humans, they have been associated with human bite infections and as a component of polymicrobial abscesses. The type species is V. parvula. [Adrien Veillon, French bacteriologist, 1864–1931]

- V. alcalescens alcalescens a bacterial subspecies found primarily in the mouth of humans but occasionally in the buccal cavity of rabbits and rats; it is the type subspecies of the species V. alcalescens.

- V. alcalescens dispar a subspecies found in the mouth and respiratory tract of humans.

- V. alcalesens a bacterial species found in the saliva of humans and other animals.

- V. atypica SYN: V. parvula atypica.

- V. parvula a bacterial species found normally as a harmless parasite in the natural cavities, especially the mouth and digestive tract, of humans and other animals; it is the type species of the genus V..

- V. parvula atypica a bacterial subspecies found in the buccal cavity of rats and humans. SYN: V. atypica.

- V. parvula parvula a bacterial subspecies found in the mouth or the intestinal or respiratory tract of humans; it is the type subspecies of the species V. parvula.

- V. parvula rodentium a bacterial subspecies found in the buccal cavity and intestinal tract of hamsters, rats, and rabbits. SYN: V. rodentium.

- V. rodentium SYN: V. parvula rodentium.

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Veil·lon·el·la (va″on-elґə) [Adrien Veillon] a genus of gram-negative bacteria of the family Acidaminococcaceae consisting of small, non–spore-forming cocci occurring in pairs or short chains; organisms are anaerobic, chemo-organotrophic, and oxidase- and catalase-negative, and do not ferment carbohydrates. They are found as normal inhabitants of the mouth and gastrointestinal tract, and vagina and have been implicated in a variety of infections, especially in immunocompromised persons. The type species is V. parґvula.