A 30-year-old male patient with no preexisting diseases presented to our emergency department due to right-sided headache and photophobia. Cranial magnetic resonance imaging (cMRI) identified a mass measuring approximately 4 cm in diameter in the right frontal operculum with pronounced perifocal edema and midline shift consistent with a brain abscess. Calculated antimicrobial therapy with flucloxacillin, ceftriaxone, and metronidazole was administered, and microsurgical abscess evacuation via craniotomy was performed. Molecular genetic and culture investigations of abscess material yielded evidence of Streptococcus anginosus, whereupon antimicrobial therapy was switched to penicillin G and metronidazole. A rapid clinical improvement was observed in the further course. Diagnostic investigations of the surrounding area by means of transesophageal echocardiography and abdominal computed tomography revealed no further sites of infection. When questioned, the patient reported having undergone professional dental cleaning 3 weeks previously. Given that S. anginosus makes up part of the physiological oral flora, it is highly likely that bacteremia occurring during dental cleaning was causal in the development of the brain abscess.
