Aminoglycoside Therapy of Gram-Negative Bacillary Meningitis

The distribution of aminoglycosides in the cerebrospinal fluid (CSF) space was examined after intralumbar, intraventricular, and systemic administration during seven episodes of gram-negative bacillary meningitis. Six episodes were associated with culture proved ventriculitis. Parenteral therapy with gentamicin or tobramycin produced low concentrations of aminoglycoside (less than 1.0 mug/ml) in the lumbar, ventricular, and cisternal CSF. Administration of 5 to 10 mg of aminoglycoside into the lumbar intrathecal space resulted in 27-81 mug/ml in the lumbar CSF, but 0-2.1 mug/ml in the ventricular CSF. In contrast, aminoglycoside administered into the cerebral ventricles produced concentrations in the lumbar CSF of 11.5-27.5 mug/ml and ventricular CSF of 12.8-40 mug/ml. All six episodes treated via the ventricular route resulted in a bacteriologic cure. Intraventricular administration of aminoglycosides offers a reliable means of achieving high aminoglycoside concentrations throughout the subarachnoid space.