Concomitant Liver and Brain Abscesses Caused by Parvimonas Micra

Abstract

Anaerobic infections have been reported to be responsible for 3-10% of pyogenic liver abscesses in Korea, and reported anaerobes include Fusobacterium, Bacillus fragilis, and Bacteroides melaninogenicus. Parvimonas micra is an anaerobic, Gram-positive, non-spore-forming bacterial species and a constituent of normal flora on skin, vagina, gastrointestinal tract, and oral cavity that can cause opportunistic infections. However, it has only rarely been reported to be a cause of liver abscess; only one such case has been reported in Korea. We experienced a case of concomitant liver and brain abscesses caused by Parvimonas micra in a non-immunodeficient 65-year-old female patient without diabetes or periodontal disease. Parvimonas micra infection was confirmed by blood culture using VITEK ® 2 cards and by bacterial 16s ribosomal RNA gene sequencing. We conclude that we should not overlook anaerobes as a cause of liver abscess.

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

“…It is worth mentioning that standard bacterial culturing was ineffective to detect Pm in these four cases, and the authors had to use gene amplification of bacterial samples and sequencing technologies to identify the pathogen. [8,10,18] Our report supports the diagnostic value of 16S rRNA to detect Pm in patients with culture-negative brain abscesses. [8,10,21] e application of matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry has also proven useful to detect Pm.…”

“…[8,10,18] Our report supports the diagnostic value of 16S rRNA to detect Pm in patients with culture-negative brain abscesses. [8,10,21] e application of matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry has also proven useful to detect Pm. [7] e challenging identification of this strict anaerobe, particularly when antibiotic therapy was started before collecting the specimen, might have contributed to the infrequent reporting of brain abscesses caused by Pm.…”

“…Among the cases with a known source of infection, a dental origin was reported for all but one case with esophageal pleural fistula. [1,8,10,13] It is remarkable that all the patients in this series were in good general health, except for one with an esophageal carcinoma. In agreement with a recent systemic review of infections caused by Pm, this case series of brain abscesses sustains that most Pm infections occur in a polymicrobial environment.…”

“…[3,7,9] Even poor oral hygiene alone has proven enough to lead to brain abscesses. [8] After a thorough literature review, we found only ten previous cases of brain abscesses in which Pm, an organism typically found in the human oral flora, was isolated [ Table 1]. Among the cases with a known source of infection, a dental origin was reported for all but one case with esophageal pleural fistula.…”

“…[10] Our patient, as well as one reported 10 years ago by Kwon et al, had a solitary brain abscess in which orally originated Pm was identified as the lone causative microorganism. We discuss the diagnostic and treatment strategies of these two cases in addition to those of nine patients with either multiple brain abscesses due to Pm monomicrobial infection, [8,18] or polymicrobial brain abscess including Pm. [1,13,14,23] Odontogenic brain abscesses caused by Pm are lifethreatening unless correctly managed by a multidisciplinary team including neurosurgeons, infectious-disease specialists, and maxillofacial surgeons.…”