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Veillonelles
Medical expert of the article
Last reviewed: 08.07.2025
Veillonella is one of the dominant (quantitatively) inhabitants of the oral cavity and the mucous membrane of the gastrointestinal tract. They are obligate anaerobic gram-negative small coccobacteria. These bacteria are immobile and do not form spores. In a smear from a pure culture, they are located as spherical diplococci, clusters in the form of bunches or short chains.
Isolated colonies of Veillonella on lactate agar reach 1-3 mm in diameter, are smooth, convex, lenticular or diamond-shaped, opal or yellow-white in color, and soft in consistency.
In the oral cavity there are representatives of two species: V. parvula and V. alcalescens. They inhabit the mucous membrane of the oral cavity, palate, and are dominant in saliva and salivary gland ducts.
Due to the peculiarities of biochemical activity - Veillonella ferment acetic, pyruvinophane and lactic acids well - they play an important role in the oral cavity, neutralizing the acidic products of metabolism of other bacteria. This allows Veillonella to be considered as antagonists of cariogenic streptococci and the most important factor in human resistance to dental caries. The pathogenic role of Veillonella in the development of inflammatory processes in the oral cavity has not been proven, although they are often isolated from purulent exudate in association with other anaerobic bacteria.