Reevaluation of an experimental streptococcal canine brain abscess model

An experimental cerebral abscess model in which alpha-hemolytic Streptococci were inoculated into the brain parenchyma of dogs was evaluated for assessment of antimicrobial therapy. Intracerebral ring-enhancing lesions were visualized by computerized tomography, but they resolved after time without therapeutic intervention. Histopathological study demonstrated evolution of the lesions into sterile granulomas. Quantitative cultures were performed and uniformly became sterile in the early cerebritis stage, approximately 3 days after bacterial inoculation. Therefore, this brain abscess model should not be utilized for the evaluation of new antimicrobial treatment regimens. Rather, other models which document persistent viable organisms within cerebral abscesses need to be developed.