Neonatal meningitis caused by Bifidobacterium breve.

We are reporting a male neonate with meningitis caused by Bifidobacterium breve. This is only the second case reported so far to our knowledge. The patient's clinical course was excellent and inflammatory indications, such as serum C-reactive protein, were weak. Although the antibiotics used for the patient were effective against this bacterium both in vitro and in vivo, two relapses occurred which might have been caused by an incomplete remission due to the low permeability of antibiotics through the blood-brain barrier under the very mild inflammation of the meninges, and also by the discrepancy between minimum bactericidal concentrations (MBC) and minimum inhibitory concentrations (MIC). Anaerobic meningitis is very rare, but it may exist in more than the reported cases. Anaerobic culture should be performed for patients with culture-negative purulent meningitis.