Rifampin reduces production of reactive oxygen species of cerebrospinal fluid phagocytes and hippocampal neuronal apoptosis in experimental Streptococcus pneumoniae meningitis

Abstract

Bacterial compounds induce the production of reactive oxygen species (ROS) in meningitis. Rifampin releases smaller quantities of proinflammatory compounds from Streptococcus pneumoniae than do beta-lactam antibiotics. Therefore, rabbits infected intracisternally with S. pneumoniae were treated intravenously either with rifampin 5 mg/kg/h or ceftriaxone 10 mg/kg/h (n = 9 each). Before initiation of antibiotic treatment, a strong positive correlation between ROS production of cerebrospinal fluid (CSF) phagocyte populations and bacterial CSF titers was observed (granulocytes: r(s) = .90, P < .0001; monocytes: r(s) = .81, P < .0001). CSF leukocytes from rifampin-treated rabbits produced less ROS (monocytes at 2 h after initiation of treatment: P = .045; at 5 h: P = .014; granulocytes at 5 h: P = .036) than did leukocytes from animals receiving ceftriaxone. The CSF malondialdehyde concentrations and the density of apoptotic neurons in the dentate gyrus were lower in rifampin- than in ceftriaxone-treated animals (P = .002 and .005). The use of rifampin to reduce the release of ROS and to decrease secondary brain injury appears promising.