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Rothia dentocariosa

Cell Structure

Rothia dentocariosa is a common bacteria found in the mouths flora. Rothia dentocariosa is aerobic, gram positive, and can be coccal to rod shaped. The bacteria on agar plates normally tends to be off white, smooth, and creamy but can also be rough and wrinkled (1).

Description and Significance

Rothia dentocariosa was first isolated from human mouth flora in 1949.The bacteria was thought to be part of the groups Actinomyces dentocariosus, Nocardia dentocariosus, and Nocardia salivae until a separate genus of Rothia was created in the family Actinomycetaceae in the early 1960’s (3). A distinguishing feature of Rothia dentocariosa that helped set it apart from Actinomycetes was a study done on the composition of the cell wall. It was found that the cell wall of Rothia dentocariosa contained fructose, glucose, and ribitol components. Fructose had not been found in any other Actinomycetes and is a characteristic sugar of the cell wall of Rothia (5).

Disease and Medicine

The bacterium is found in normal mouth flora but also can be the cause of disease. One infection is endocarditis which affects the inner lining of the heart. This occurs when Rothia dentocariosa spreads into the bloodstream and attaches to the damaged areas of the heart. Endocarditis mainly effects people with poor oral dentition (2). Since Rothia dentocariosa is a bacterium penicillin is commonly used during infections. Other antibiotics are also used but penicillin is normally the treatment of choice. Rothia dentocariosa is also very common in individuals with carious lesions, tooth decay or cavities. In one study 95 different taxa were found in the sampled patients but dentocariosa was one of only three found in every patient showing that it is a common bacteria found in dental caries (6).

Morphology

One uncommon feature of Rothia dentocariosa is the presence of multiple different morphologies. Initially many thought that the different variances in morphology may be due to different DNA compositions. A study was done looking at the GC content, guanine and cytosine, and the melting point of purified DNA extract from coccal and filamentous strains. The study proved that the melting points and GC content were almost identical showing no correlation that multiple species may be present (4).

References

1. Barksdale L. 1979. Identifying Rothia dentocariosa. Annals of Internal Medicine. 91(5):786-788.

2. Braden DS, Feldman S, Palmer AL. 1999. Rothia Endocarditis in a Child. Southern Medical Journal. 92(8):815-816.

3. Brown JM, Georg LK, Waters LC. 1968. Laboratory Identification of Rothia dentocariosa and Its Occurrence in Human Clinical Materials. Applied Microbiology. 17(1):150-156.

4. Hammond BF. 1970. Deoxyribonucleic Acid Base Composition of Rothia dentocariosa as Determined by Thermal Denaturation. Journal of Bacteriology. 104(2):1024-1026.

5. Hammond BF. 1970. Isolation and Serological Characterization of Wall Antigen of Rothia dentocariosa. Journal of Bacteriology. 103(3):634-640.

6. Munson MA, Banerjee A, Watson TF, Wade WG. 2004. Molecular Analysis of the Microflora Associated with Dental Caries. Journal of Clinical Microbiology. 42(7):3023-3029.