Etiological agents and predisposing factors of intracranial abscesses in a Greek university hospital.

The bacteriology for 21 patients with brain abscesses is presented and correlated with their predisposing conditions. Chronic otomastoiditis was the most common predisposing factor, and the overall most frequent infected sites were the frontal and temporal regions. Gram-negative non-sporeforming anaerobes of the genus Bacteroides and Fusobacterlum followed by aerobic streptococci were the predominant pathogens. Enterobacteria were only identified in postcraniotomy abscesses, while a substantial number of fastidious species was detected in suppurations related to congenital heart disease. Altogether, anaerobes alone were recovered in seven patients, aerobes alone in six, and mixed aerobes and anaerobes in four patients. These findings confirm the predominant role of anaerobes in the etiology of intracranial suppurations.