Type III group B streptococcal infections in mice: bacteremia and meningitis following oral inoculation.

The successful production of disease in mice by a type III group B streptococcus is described in this report. When injected intravenously, 106 organisms produced a fulminating sepsis and resulted in 100% mortality within 48 h. Inoculation of 108 - 109 organisms directly onto the surface of the oropharynx progressed to bacteremia and meningitis in greater than 50% of animals. In a group of mice treated with penicillin immediately after oropharyngeal inoculation, the incidence of invasive bacteremia was reduced to 30%. The use of this animal model for studying the pathogenesis and treatment of experimentally produced meningitis and eradication of oropharyngeal colonization is discussed.