Atenuação do comprometimento cognitivo pelo antibiótico não-bacteriolítico daptomicina em ratos wistar submetidos à meningite pneumocócica

Abstract

Background: Streptococcus pneumoniae is associated with neurologic sequels, such as, seizures, sensory-motor deficits, hearing loss, learning and memory impairment, which can occur in approximately 30 to 52% of surviving patients. Neuronal damage can be caused by intense inflammatory reaction and direct effects of the bacteria virulence factors. The aim of the present study was to evaluate the effects of the nonbacteriolytic antibiotic daptomycin versus ceftriaxone on behavioral parameters in adult Wistar rats submitted to pneumococcal meningitis. Methods: The animals underwent a magna cistern tap receiving either 10 μl sterile saline as a placebo or an equivalent volume of a S. pneumoniae suspension at the concentration of 5x109 cfu/mL and they were randomized into different groups: sham (placebo); meningitis with ceftriaxone treatment (100 mg/kg during 7 days) and meningitis with daptomicyn treatment (50 mg/kg, during 7 days). Ten days after meningitis induction the animals were submitted to four behavioral tasks: habituation to an open field, step-down inhibitory avoidance, continuous multiple-trials step-down inhibitory avoidance task and object recognition. Results: Ten days after induction we verified that the meningitis group with daptomycin treatment showed retention of aversive memory; it presented memory of the object recognition at short term and long term. In continuous multiple-trials stepdown inhibitory avoidance task the meningitis group with ceftriaxone treatment required approximately two times more stimulus to reach the acquisition criterion when compared with meningitis group with daptomycin treatment. However, in habituation memory there were no differences in the number of crossings and rearings in training and task sessions demonstrating habituation impairment to the environment task in both meningitis groups. Conclusions: The evidence of the present study shows the potential alternative of the treatment with daptomycin in preventing learning and memory impairments caused by pneumococcal meningitis. Further investigations are necessary to provide support for evaluation of daptomycin as an alternative treatment of bacterial meningitis.