Brain abscess due to Streptococcus acidominimus: first case report

BACKGROUND: Streptococcus acidominimus resembles Streptococcus viridans, but they can now be differentiated by phenotypic studies. Only a single previous case of pneumonia, pericarditis, and meningitis has been reported. CASE DESCRIPTION: We recently encountered a patient with brain abscess from which S acidominimus was isolated after initially being recorded as S viridans. Because 49% of all S viridans isolated from abscesses are resistant to beta-lactam antimicrobials, speciation is important as well as in vitro sensitivity testing. Streptococcus acidominimus is ordinarily sensitive to beta-lactams, and the use of ceftriaxone for 6 weeks successfully resulted in cure of the brain abscess. CONCLUSION: The use of speciation in treatment of S viridans should improve clinical outcomes.