Neisseria meningitidis Strain of Unknown Serogroup, China

摘要

To the Editor: Neisseria meningitidis is a major public health hazard in many parts of the world. This organism is classifi ed into 13 serogroups, and most meningococcal disease is caused by strains that express 1 of the 5 types of capsular polysaccharides (A, B, C, Y, and W135). In the natural reservoir of the human nasopharynx, strains of N. meningitidis that do not fi t into 1 of the 13 serogroups and are presumably unencapsulated are common. By contrast, rare meningococcal diseases are caused by these nonserogroupable strains. In this article, we describe a case of N. meningitidis infection caused by a nonserogroupable strain in the People's Republic of China and the genotype characteristics of this strain.The patient was a 6-month-old boy who was admitted to a local hospital in Beijing in May 2009. The infection started suddenly with high fever (39°C). N. meningitidis infection was confi rmed on the basis of the clinical signs and results of laboratory examination. Nausea, vomiting, and neck stiffness developed, and the patient lost consciousness. Physical examination showed a positive Kernig sign and negative Brudzinski sign. The patient's cerebrospinal . uid sample was injected into chocolate agar, in which microbial growth was observed after 24 hours. The API NH system (bioMérieux, Marcy-Etoile, France) showed that the isolate was N. meningitidis. However, this strain could not be placed in a serogroup, even after specifi c antiserum (Remel, Lenexa, KS, USA) was used. No other disease with complement defi ciency was detected in the patient. The patient's infection was treated with antimicrobial drugs, and he recovered completely