Meningococcal pneumonia in Japan: A case report and literature review

Neisseria meningitidis often causes meningitis and meningococcemia; however, meningococcal pneumonia is quite rare. Herein, we report a case of non-invasive meningococcal pneumonia initially misdiagnosed as pneumonia due to Moraxella catarrhalis on the basis of a Gram stain in a 43-year-old woman with asthma, type 2 diabetes mellitus, and schizophrenia. She visited our hospital following a 3-day history of fever, productive cough, and shortness of breath. Since her sputum smear revealed Gram-negative diplococcus and the chest radiograph showed infiltration in the lower right lung field, her initial diagnosis was pneumonia caused by M. catarrhalis. However, the next day, the sputum culture colonies were unlike those of M. catarrhalis, and matrix-assisted laser desorption/ionization time of flight mass spectrometry analysis revealed the pathogen to be N. meningitidis. As a result, we administered the appropriate treatment and ensured adequate infection prevention and control measures including, droplet precautions and prophylaxis provided to close contacts. Secondary infection did not occur. Although meningococcal pneumonia is not common, physicians should consider N. meningitidis when Gram-negative diplococci are observed in respiratory specimens, as N. meningitidis cannot be distinguished from M. catarrhalis with Gram staining alone. Moreover, it is also important to monitor the appearance of the pathogenic colonies and to closely coordinate with laboratory technicians to determine appropriate treatments. In this article, we review the previous case reports of meningococcal pneumonia reported in 1984-2015 in Japan, summarizing the clinical characteristics and comparing previous reviews of the literature.