Native-valve endocarditis due to Neisseria sicca: case report and review.

Many species of the Neisseria, gram-negative diplococci that are frequent respiratory commensals in humans, have been regarded as being nonpathogenic or as causing disease in only immunocompromised hosts; in contrast, gram-negative diplococci such as Neisseria meningitidis and Neisseria gonorrhoeae are known pathogens. We report a case in which Neisseria sicca was the cause of serious infection (with catastrophic consequences) in an immunocompetent patient and review the world literature on endocarditis due to N. sicca.