The significance of nongonococcal, nonmeningococcal Neisseria isolates from blood cultures

Nongonococcal, nonmeningococcal neisseriae are part of the normal respiratory flora and infrequently cause disease. These organisms include Neisseria lactamica, Neisseria mucosa, Neisseria sicca, Neisseria flavescens, Neisseria subflava , Neisseria perflava , Neisseria flava , and Branhamella catarrhalis (previously classified as Neisseria catarrhalis). Blood cultures positive for these bacteria have been associated with serious infections, including endocarditis, septicemia, and meningitis. In a retrospective survey of a 10-year period, 1970-1980, eight patients were identified at Hartford Hospital (Hartford, Conn.) whose blood cultures were positive for nongonococcal, nonmeningococcal neisseriae. In four patients, the neisseria blood isolates were associated with serious infections: two with endocarditis, one with sepsis, and one with meningitis. In four other patients, the neisseria blood isolates were contaminants.