Characteristics of Brain Abscess with Isolation of Anaerobic Bacteria

Abstract

In view of its localization, brain abscess (BA) usually requires medical and surgical care. A broad spectrum of bacteria is involved. Recent reports stress the increasing frequency of anaerobes, but their impact has not been well evaluated. A retrospective review was conducted of all episodes of documented BA admitted in a tertiary-care hospital over a 10 y period. BA due to anaerobic bacteria (group A) were compared with other cases (group B) to determine the frequency and eventual characteristics of BA with isolated anaerobic bacteria. Between 1991 and 2000, BA were diagnosed in 42 patients (28M, 14F, mean age 54.6 y). No differences in clinical features and laboratory findings were found between patients with BA caused by anaerobic (n = 22) and only aerobic (n = 20) bacteria. Using appropriate microbiological techniques, 41 anaerobic bacteria strains were isolated in 22 of 42 patients (52.4%) with BA. Anaerobic bacteria were associated with aerobic strains in 5 patients (12%), whereas in 17 patients (40.5%) only anaerobic strains were isolated in cerebral puncture cultures. The most frequently isolated species were Fusobacterium nucleatum (n = 14), Prevotella sp. (n = 8), Actinomyces sp. (n = 6) and Bacteroides sp. (n = 4). Compared with group B, group A had more cases of a single abscess (p = 0.03) and ear, nose and throat (ENT) as a source of infection (p = 0.04), and seemed to have a better outcome (p = 0.07). These results emphasize the important role that anaerobic bacteria play in BA. The presence of such pathogens must be evoked when faced with a single abscess, an ENT infection, or both. Therapy should take into account this high frequency.

Pyogenic brain abscess

“…94,96,104 After 2000, the mortality rate was reported to be between 17 and 32%. 49,58,62,78,79 This discrepancy may be mainly due to the drastic changes in epidemiology taking place nowadays. Compared to the previous reports, the incidence of brain abscesses caused by sinus/otitis infection decreased, whereas those associated with immunodeficiency increased markedly.…”

Human Infection withFusobacterium necrophorum(Necrobacillosis), with a Focus on Lemierre's Syndrome

“…Anaerobes are an important cause of cerebral abscess, and fusobacteria are among the most common isolates (56,145,244). However, F. necrophorum tends either to be a minority isolate (56,145) or not to be found at all (244), with F. nucleatum being a much more common isolate.…”

“…However, F. necrophorum tends either to be a minority isolate (56,145) or not to be found at all (244), with F. nucleatum being a much more common isolate. The current literature search identified 9/251 F. necrophorum patients with cerebral abscess, ranging from 5 to 45 years in age and with a median age of 17 (9,109,183,203,204,259,269,313,392).…”

Prevotella colorans sp. nov., isolated from a human wound

“…acute dental abscess), the central nervous system (e.g. brain abscess), as well as the skin (soft tissue abscess) (Le Moal et al, 2003;Mehmood et al, 2014;Robertson & Smith, 2009). …”