Parvimonas micra: A potential causative pathogen to consider when diagnosing odontogenic brain abscesses

Abstract

Background: Brain abscess is a life-threatening entity which requires prompt and long-term antibiotic therapy, generally associated with surgical drainage, and eradicating the primary source of infection. Parvimonas micra (Pm) has only been reported once before as the lone infecting organism of an orally originated, solitary brain abscess. Diagnosing brain abscesses caused by this Gram-positive anaerobic coccus, constituent of the oral cavity flora, is challenging, and an optimal treatment regimen has not been well established. We report the diagnosis and successful treatment of a Pm caused odontogenic brain abscess. Case Description: A 62-year-old immunocompetent male with a right-parietal brain abscess presented with headache and seizures. He was started on empirical antibiotic therapy and subsequently underwent surgical drainage. The only source of infection found was severe periodontitis with infected mandibular cysts. Thus, tooth extraction and cyst curettage were performed 1 week after brain surgery. Cultures of brain abscess fluid were negative, but amplification of bacterial 16S ribosomal RNA (rRNA) with polymerase chain reaction demonstrated Pm. After 3 weeks of intravenous ceftriaxone and metronidazole, the patient was switched to oral metronidazole and moxifloxacin for 6 weeks. Conclusions: This case highlights the potential risk of untreated dental infections causing brain abscesses. Pm should be considered as a possible pathogen of odontogenic brain abscesses despite its presence usually not being detected by standard bacterial cultures. Therefore, 16S rRNA gene sequencing analysis is strongly recommended for bacterial identification before defining brain abscesses as cryptogenic.

Stroke Caused by Vasculitis Induced by Periodontitis-Associated Oral Bacteria after Wisdom Teeth Extraction

“…In the context of the case presented here, the identified pathogens— F. nucleatum , P. gingivalis and P. micra —are anaerobic bacteria, often linked with periodontal diseases, and have been implicated in distant site infections, including brain abscesses [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. Yet their direct association with ischemic stroke remains rare and underreported.…”

Classification of salivary bacteriome in asymptomatic COVID-19 cases based on long-read nanopore sequencing

“…45,46 P. micra was a part of normal commensals in the oral cavity, gastrointestinal tract, genitourinary tract, and skin. Many reports presented P. micra to be associated with several diseases including periodontitis, 47 abdominal abscesses, 48 arthritis, 49 intracranial infection, 50 and bloodstream infection. 51 D. pneumosintes was reported to be frequently associated with gingivitis, periodontitis, and progression of periodontitis.…”

Erosion of the sella turcica and pituitary expansion secondary to polymicrobial brain abscesses: a case report

“… P. micra are anaerobic Gram-positive cocci and a commensal organism of the oral cavity and gastrointestinal tract. They have been reported to cause odontogenic BAs; however, the pathogen is usually not identified on standard bacterial cultures and require a 16S rRNA gene sequencing analysis [ 20 ]. In the case of the patient, MALDI-TOF MS successfully identified P. micra .…”