[Experimental meningitis due to a high-level cephalosporin-resistant strain of Streptococcus pneumoniae serotype 23F].

INTRODUCTION:The increasing prevalence of high-level cephalosporin-resistant strains of Streptococcus pneumoniae could complicate the treatment of severe infections such as meningitis. There are still questions as to the characteristics of these strains, their ability to produce severe infection, and the inflammatory response they induce in CSF. METHODS:Using a rabbit model of meningitis, we sought to determine the pathogenicity and differences in inflammatory parameters in two serotype 23F S. pneumoniae strains with different susceptibility to betalactams. Minimal inhibitory concentrations of the two strains were as follows: strain A--PEN 4 micro g/mL, CRO/CTX 2 micro g/mL--and strain B--PEN 0.12 micro g/mL, CRO/CTX 32 micro g/mL. RESULTS:Strain A resulted in a greater incidence of secondary bacteremia and higher inflammatory parameters during the early phases of infection. Strain B caused brain edema, a more severe inflammatory response and significantly higher mortality at the end of the experiment. CONCLUSIONS:Both strains induced meningitis in the animal model. The differences in inflammatory response produced by the two strains could be related to the variations that determine the betalactam resistance level.