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Neisseria cinerea
Scientific classification
Kingdom:
Phylum:
Class:
Order:
Family:
Genus:
Neisseria
Species:
N. cinerea

Neisseria cinerea is a commensal species grouped with the Gram-negative, oxidase-positive, and catalase-positive diplococci.[1] It was first classified as Micrococcus cinereus by von Lingelsheim in 1906.[2] Using DNA hybridization, N. cinerea exhibits 50% similarity to Neisseria gonorrhoeae and this is distinct from it.[3]

Classification[edit]

N. cinerea has been formerly classified as many other organisms, including Moraxella catarrhalis and Neisseria pseudocatarrhalis.[4] It is often mistaken for N. gonorrhoeae as they are morphologically and biochemically very similar.[5] They are isolated from similar infections, including endocervical and rectal infections, neonatal conjunctivitis, and lymphadenitis.[6] N. cinerea has even been isolated on gonococcal selective media specifically made to isolate N. gonorrhoeae.[7]

Colony Morphology[edit]

One important difference between N. cinerea and N. gonorrhoeae is that N. cinerea is slightly more pigmented and exhibits a golden-brown rather than a pinkish-brown pigmentation.[8] The average diameter of N. cinerea colonies varies but stays around 1-2 mm.[9] The colonies are convex, translucent, and glistening.[10] There is no change in the color of the media used to isolate N. cinerea before or after staining with Lugol's iodine.[11]

Biochemical Processes[edit]

N. cinerea can produce acid from glucose like N. gonorrhoeae but it will then oxidize the acid to carbon dioxide.[12] Although it can break down glucose, it is unable to use glucose or other carbohydrates for energy, making it asaccharolytic.[13] In addition, N. cinerea will react in coagglutination serologic tests and, like N. gonorrhoeae, it produces the enzyme hydroxyprolylaminopeptidase.[14] N. cinerea does not reduce nitrate, but it does reduce nitrite.[15] Proline, arginine, cystine, and cysteine are required for its growth.[16] N. cinerea does not react with antigonococcal protein I monoclonal antibodies and does not produce immunoglobulin A protease, unlike N. gonorrhoeae.[17] Also unlike N. gonorrhoeae, N. cinerea is not resistant to the antibiotic colistin and it can grow on Mueller-Hinton agar and trypticase soy agar.[18]

Disease[edit]

Neisseria cinerea is classified as a non-pathogenic bacterium, but has been isolated from numerous infections including acute meningitis.[19] Many studies indicate that N. cinerea colonizes the oropharynx and sometimes the genital tract.[20] A few infections which could possibly be caused by N. cinerea have been reported.[21] However, in each case the organism was misidentified as N. flavescens, N. gonorrhoeae, or M. catarrhalis.[22]

See Also[edit]

Notes[edit]

  1. ^ Knapp 1984.
  2. ^ CDC 2008.
  3. ^ CDC 2008.
  4. ^ CDC 2008.
  5. ^ CDC 2008.
  6. ^ CDC 2008.
  7. ^ CDC 2008.
  8. ^ CDC 2008.
  9. ^ Knapp 1988.
  10. ^ Knapp 1988.
  11. ^ Knapp 1988.
  12. ^ CDC 2008.
  13. ^ Knapp 1984.
  14. ^ CDC 2008.
  15. ^ Knapp 1984.
  16. ^ Knapp 1984.
  17. ^ Knapp 1984.
  18. ^ Knapp 1984.
  19. ^ Knapp 1984.
  20. ^ Knapp 1988.
  21. ^ Knapp 1984.
  22. ^ Knapp 1984.

References[edit]

  • Centers for Disease Control and Prevention (2008). "Neisseria cinerea"
  • Knapp, J. S. et al. (1984). "Characterization of Neisseria cinerea, a nonpathogenic species isolated on Martin-Lewis medium selective for pathogenic Neisseria spp."
  • Boyce, J. M., et al. "Nosocomial pneumonia caused by a glucose-metabolizing strain of Neisseria cinerea." Journal of clinical microbiology 21.1 (1985): 1-3.
  • Knapp, J. S., and E. W. Hook. "Prevalence and persistence of Neisseria cinerea and other Neisseria spp. in adults." Journal of clinical microbiology 26.5 (1988): 896-900.