A previously healthy 22-year-old male was admitted to the intensive care unit following a motor vehicle accident. His injuries included a right subdural hematoma, subarachnoid hemorrhages, a left hemopneumothorax, a hemoperitoneum secondary to a splenic rupture, multiple rib fractures with flail chest, and fractures of the left scapula and left clavicle. The subdural hematoma was evacuated by means of a decompressive craniotomy on hospital day 1, and an external ventricular drain was inserted. A removal of the spleen was executed the day after. The patient's initial hospital course was complicated by a pneumonia due to Haemophilus parainfluenzae and Enterobacter cloacae, which was treated with cefotaxime for 7 days. On day 17 postcraniotomy, the patient developed a fever. Twelve blood cultures taken from the arterial catheter and one urine culture were negative. Chest and abdominal tomography showed no septic focus. A cerebrospinal fluid (CSF) sample was collected from the external collection bag while the external ventricular drain was in place. Analysis showed a protein level of 2.39 g/liter (range, 0.10 to 0.20 g/liter) and a glucose level of 3.8 mmol/liter (range, 2.7 to 3.9 mmol/liter), whereas the glycemic level was 6.4 mmol/liter, with 24 leukocytes/mm3 (90% neutrophils) and 9 erythrocytes/mm3, and no organism was seen on Gram stain. The cultures remained negative after 24 h and after 48 h of incubation. After 4 days, thin translucent pinpoint colonies were observed on a chocolate agar plate. Three other CSF samples collected from the external collection bag on days 19, 21, and 23 postcraniotomy were positive for the same organism, with increased numbers of white blood cells (62 cells/mm3, 70 cells/mm3, and 250 cells/mm3, respectively). In all, during hospitalization, among 21 samples of CSF collected from the external collection bag, 4 were positive for this organism. Gram stains of the colonies were negative. Microscopic examination revealed small colonies as shown in Fig. 1.