Direct demonstration of Staphylococcus biofilm in an external ventricular drain in a patient with a history of recurrent ventriculoperitoneal shunt failure

Abstract

External ventricular drains (EVD) are associated with a high infection rate. Early detection of infection is frequently problematic due to a lack of clinical signs and the time period required for culturing. Bacterial biofilms have been suggested to play an important role in the infection of EVD, but direct evidence is as yet lacking. We report the case of a 17- year-old male with Dandy-Walker malformation who presented with headache, nausea and drowsiness; a CT scan revealed enlarged ventricles. The patient had a history of ventriculoperitoneal shunt revision 3 weeks prior to admission. The shunt was removed on suspicion of infection and an EVD placed. Daily surveillance cultures through the EVD were negative and the EVD was replaced on day 5. Examination of the initial EVD by confocal microscopy demonstrated clear intraluminal biofilm formation; molecular analysis by PCR identified Staphylococcus aureus resident on the catheter. To our knowledge, this is the first direct demonstration of an intraluminal biofilm compromising an EVD. Despite the presence of biofilm on this catheter, the patient demonstrated no clinical signs of infection, and the routine surveillance culture was negative. Undetected biofilm may pose a latent risk on EVD and other neurosurgical catheters.