Characterization of Streptococcus constellatus strains recovered from a brain abscess and periodontal pockets in an immunocompromised patient.

BACKGROUND

There have been a number of reports of brain abscesses suggesting an odontogenic etiology. However, no efforts have been made to compare brain abscess isolates with isolates from the oral cavity using highly discriminative methods. We report a brain abscess caused by Streptococcus constellatus in an immunocompromised patient where oral infection (periodontitis) was suspected to be implicated.

METHODS

The brain abscess and oral isolates were compared by means of one phenotypic and three genetic (restriction fragment length polymorphism [RFLP], ribotyping, and random amplified polymorphic DNA [RAPD]) fingerprinting techniques.

RESULTS

The phenotypic method and RFLP showed identical profiles between brain and periodontal isolates, while ribotyping and RAPD showed very close similarity, with only one band difference in one of the three ribotypes and in one of the three polymorphic RAPD.

CONCLUSIONS

Gene transfer by genetic recombinational events in the periodontal pocket might have been responsible for the emergence of a strain variant of S. constellatus that had the potential to cause an abscess at a distant site (brain). The importance of odontogenic sources as potential foci of infection for brain abscesses is discussed.