Bacteroides fragilis meningitis in a Saudi infant: case report and literature review

BACKGROUND: Anaerobic meningitis is mainly caused by Bacteroides fragilis and it is rarely detected in children. Few cases have been reported and there is usually an underlying cause. The timing of early recognition is crucial because any delay in the diagnosis and initiation of appropriate antimicrobial therapy has a devastating outcome. Only 14 cases have been reported in 50 years. To the best of our knowledge, the present case is the first to be reported in Saudi Arabia with no underlying etiology. CASE PRESENTATION: We describe a 35-day-old male infant with culture-negative pyogenic meningitis who did not show satisfactory response to the empirical antibiotics, consequently, he developed severe subdural/epidural empyema and ventriculitis. When the drained empyema was cultured anaerobically, B. fragilis was detected and the patient improved after treatment with metronidazole combined with adjuvant surgical drainage of the empyema, and he finally had hydrocephalus. No underlying etiology was found to explain his infection. CONCLUSION: B. fragilis is an uncommon cause of meningitis that requires a high index of clinical suspicion. Any pyogenic cerebrospinal fluid with negative culture should draw the attention of physicians to an unusual organisms such as anaerobes because early identification and initiation of appropriate antimicrobials can prevent long-term morbidity and mortality.