Are the "nonpathogenic" Neisseriae pathogenic?

Neisseriae other than N. meningitidis and N. gonorrhoeae are common upper respiratory commensals, but rarely cause disease. A case of N. sicca bacteremia in an immunocompromised patient is reported, and the literature dealing with infections attributed to these usually nonpathogenic organisms is reviewed. These neisseriae have been shown to cause meningitis, endocarditis, sepsis, and some cases of pneumonia, otitis media, and sinusitis; however, their pathogenicity is doubtful in many of the reported cases of urethritis, cervicitis, and upper respiratory infection. They are not uniformly sensitive to the penicillins, so therapy should be guided by the results of antimicrobial susceptibility testing.