First case of Neisseria meningitidis capsule null locus infection in China.

Invasive meningococcal diseases are rarely caused by capsule null locus (cnl) strains, which are unencapsulated owing to an absence of capsule synthesis genes. Only a few cases of cnl meningococcemia in severely immunocompromised patients have been reported. Here, we describe and discuss the first case of invasive disease in an immunocompetent patient due to a cnl strain of Neisseria meningitidis in China. We characterize this strain and discuss the special ST-198 complex of cnl.