Brain abscess is a rare but life-threatening infection because it affects the blood supply and the brain–blood barrier, reducing the brain's resistance to bacterial and fungal infections [1,2]. The incidence of brain abscess is estimated to be approximately 0.3–1.3 per 100,000 people per year [3]. Notably, 13.6% of brain abscesses are caused by odontogenic foci, and the overall mortality rate of odontogenic brain abscesses is estimated to be 8.3% [4,5]. Only approximately 135 brain abscesses cases with odontogenic origins have been reported in the literature, and the most common microorganisms detected in conjunction with odontogenic brain abscesses are, in descending frequency, Streptococcus intermedius, Fusobacterium nucleatum, S. viridans, and S. milleri [6].

Parvimonas micra, previously known as Peptostreptococcus micros and Micromonas micros, is a gram-positive anaerobic coccus that is normally found in the oral cavity, respiratory system, gastrointestinal tract, and genitourinary tract [7]. P. micra is also commonly regarded as a putative endodontic pathogen that can be isolated from infected root canal [8]. P. micra bacteremia can cause associated infections such as spondylodiscitis, oropharyngeal infection, intraabdominal abscess, infective endocarditis, septic pulmonary embolic, and gastrointestinal tract infection [9]. However, to the best of our knowledge, few studies have examined brain abscess caused by P. micra, and only 15 cases reports have been published in the literature [1,3,7,[10], [11], [12], [13], [14], [15], [16], [17], [18]]. Herein, we report a patient with brain abscess caused by odontogenic P. micra. Relevant studies are also reviewed.