Model of Streptococcus pneumoniae meningitis in adult rats.

Abstract

The purpose of this study was to develop a model of bacterial meningitis in young adult rats for assessing the efficacy of antimicrobial agents. Sixty 200- to 300-g male Sprague Dawley CD rats were inoculated intracisternally with 5.78 log10 CFU of a clinical isolate of Streptococcus pneumoniae in 5% hog gastric mucin. Inoculated rats were assigned to six groups containing 10 animals each. Group-1 rats served as controls and did not receive antibiotics. Rats of groups 2 to 4 received (subcutaneously every 12 h) cefotaxime (25, 6.25, and 1.56 mg/kg of body weight respectively). Rats of groups 5 and 6 received ampicillin (50 and 12.5 mg/kg respectively) and gentamicin (2.0 and 0.5 mg/kg respectively). Five additional Sprague Dawley CD rats were inoculated with only gastric hog mucin and were assigned to group 7. At postinoculation day 4 all animals were euthanized. Cerebral spinal fluid was collected for culturing. Brains were harvested for histologic examination and culturing. Untreated, infected control (group-1) animals were culture-positive for S. pneumoniae in the brain and cerebral spinal fluid. Of the antibiotic regimens evaluated, only cefotaxime (25 mg/kg) eradicated bacteria from the cerebral spinal fluid and brain. Cefotaxime at 25 or 6.25 mg/kg significantly (P < or = 0.05) decreased the bacterial burden of S. pneumoniae, whereas cefotaxime at 1.56 mg/kg and ampicillin/gentamicin combinations did not. There was histopathological evidence of subacute meningitis in infected rats. No meningitis was observed in rats receiving 25 mg of cefotaxime/kg. This model demonstrates the ability to induce bacterial meningitis with S. pneumoniae in adult rats and the ability to clear infection in 90 to 100% of the animals by administration of cefotaxime at dosages of 6.25 and 25 mg/kg given subcutaneously every 12 h.

• Authors: J G Strake, M J Mitten, P J Ewing, J D Alder
• Journal: Laboratory animal science (Lab Anim Sci) Vol. 46 Issue 5 Pg. 524-9 (Oct 1996) ISSN: 0023-6764 [Print] United States
• PMID: 8905585 (Publication Type: Journal Article)

Chemical References

• Anti-Bacterial Agents
• Gentamicins
• Ampicillin
• Cefotaxime

Topics

• Ampicillin (pharmacology)
• Animals
• Anti-Bacterial Agents (pharmacology)
• Brain (microbiology, pathology)
• Cefotaxime (pharmacology)
• Cerebrospinal Fluid (microbiology)
• Disease Models, Animal
• Gentamicins (pharmacology)
• Male
• Meninges (pathology)
• Meningitis (microbiology, veterinary)
• Rats
• Rats, Sprague-Dawley (microbiology)
• Rodent Diseases (microbiology)
• Rodentia
• Streptococcus pneumoniae (isolation & purification)