Available online 16 July 2022, 102614

Anaerobes were isolated in 10% of patients with brain abscesses.

Cutibacterium acnes was the most frequently detected anaerobe.

All patients received both surgery and antimicrobial therapy.

A good outcome was obtained in all patients.

The objective of this study was to review the characteristics, causative bacteria, treatment and outcomes of brain abscesses due to anaerobes in our health setting.

A retrospective analysis of all brain abscesses caused by anaerobic bacteria over the period 2005–2021 was performed.

Out of 300 brain abscesses identified during the study period, 31 were produced by anaerobic pathogens, either alone (monomicrobial infection) or together with aerobic and/or anaerobic bacteria (polymicrobial infection). The mean age of the 31 patients was 53 years, and 61.2% were male; 51.6% of infections were polymicrobial, with only four (12.9%) caused by anaerobic bacteria alone. Forty-three anaerobic bacteria were isolated: Cutibacterium acnes in thirteen (41.9%), Parvimonas micra in eight (25.8%), and Prevotella spp. in seven (22.5%). The most frequent etiologies were local neurosurgery (13/41.9%) and contiguous otogenic, oral, or sinus foci of infection (8/28.8%). Cancer was present in eight patients (28.8%), headaches in seventeen (54.8%), and fever in nine (28.8%). All patients received both surgery and antimicrobial therapy. The abscess was in the frontal region in 12 patients (38.7%) and in the parietal region in 11 (35.4%). A good outcome was obtained in all patients.

Anaerobes were isolated in 10.3% of patients with brain abscesses in our health setting, similar to other reports. C. acnes was the most frequently detected anaerobe, especially in neurosurgical patients.

Anaerobic bacteria

Brain abscesses

C. acnes

P. micra

Neurosurgery

Antimicrobials

Excision

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