Meningitis-associated pneumococcal serotype 8, ST 53, strain is hypervirulent in a rat model and has non-haemolytic pneumolysin which can be attenuated by liposomes

Streptococcus pneumoniae causes life-threatening invasive pneumococcal disease (IPD), including meningitis. Strains of serotype 8, ST 53, are increasing in prevalence in IPD in several countries. Here we tested the virulence of such an isolate in a rate model of meningitis in comparison with a serotype 15B and a serotype 14 isolate. In the literature serotype 8 has been described as an invasive serotype in both children and adults with invasiveness determined by serotype. Therefore, the combination of our data from the in vivo rat model and in vitro primary mouse brain cells, as well as patient data has led us to propose that it is worth paying particular attention to serotype 8 strains of ST 53, possessing a thick capsule and non-haemolytic pneumolysin.