Aerotolerant Clostridium tertium brain abscess following a lawn dart injury.

A young girl developed an intracranial abscess and necrotizing cellulitis following penetrating injury from a lawn dart. Initial identification of a gram-positive rod growing aerobically from clinical specimens was as a Bacillus organism, but the observation that the isolate grew poorly in subcultures for susceptibility testing but quite well under standard anaerobic culture techniques led to the identification of the organism as an aerotolerant Clostridium tertium. Early management of penetrating head trauma should include cranial imaging studies to detect fractures and intracranial pathology. Clinical microbiologists and clinicians should be aware of the phenomenon of aerotolerance in anaerobic bacteria to avoid errors in choice of antibiotic therapy.