Neisseria meningitidis vs Neisseria gonorrhoeae- 32 Differences

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Neisseria meningitidis and Neisseria gonorrhoeae, are obligate human pathogens that cause distinctly different disease syndromes. They are both Gram negative diplococci, non-sporing, oxidase positive and difficult to differentiate on morphological and cultural characteristics.

Differences between Neisseria meningitidis and Neisseria gonorrhoeae

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However, they can be differentiated on the following grounds:

S.N.

Character

Neisseria gonorrhoeae

Neisseria meningitidis
1.       Commonly Called Gonococcus Meningococcus
2.       Causative agent of Sexually transmitted disease- Gonorrhoea Causes a range of diseases embraced by the term invasive meningococcal disease. Most commonly cerebrospinal meningitis.
3.       Cell Morphology Kidney shaped with apposing ends concave. Semicircular diplococcus with flat apposing ends.
4.       Capsule Absent Capsule is present which is anti-phagocytic and an important virulence factor.
5.       Pili N. gonorrhoeae most often moves using one retracting pilus. N. meningitidis most often move using four pili.
6.       Plasmids Usually possess plasmids, coding for drug resistant genes. Rarely have plasmids
7.       Form Predominantly exist in

intracellular form

 Exist in both intra· and

extracellular forms
8.       Movement Movement of N. gonorrhoeae occurs at lower speed. Movement of N. meningitidis occurs faster with a larger number of retracting pili.
9.       Growth on Blood Agar N. gonorrhoeae grow less well on blood agar than N. meningitidis. N. meningitidis grow well on blood agar than N.  gonorrhoeae
10.    Culture medium Contain antimicrobials that inhibit the growth of organisms other than N. gonorrhoeae; typically vancomycin (inhibits Gram-positive bacteria), colistin (inhibits gram-negative bacteria including the commensal Neisseria spp.), trimethoprim (inhibits swarming of Proteus spp.) and nystatin or amphotericin B (antifungal agents). Blood agar, trypticase soy agar, supplemented chocolate agar, and Mueller-Hinton agar.
11.    Growth Rate Slower than Meningococcus. Slow
12.    Fastidious Most fastidious among Neisseria spp. Comparatively less fastidious.
13.    Colony morphology N. gonorrhoeae form smooth, round, moist, uniform grey/ brown colonies with a greenish colour underneath on primary isolation medium.

Mostly, has a irregular margin.

 N. meningitides would form smooth, round, moist, uniform

large grey/brown colonies with a glistening surface and entire edges.
14.    Sugar Fermentation Produce acid from glucose only Produce acid from glucose and maltose.
15.    Maltose Fermentation No Yes
16.    Nitrite Reduction N. gonorrhoeae doesn’t reduce nitrites. N. meningitidis can reduce nitrites in low concentrations.
17.    Autolysis May autolyse Autolyse
18.    Glutamylaminotransferase Non-producer Producer
19.    Β-Lactamase Production Common Rare
20.    Antigen Heterogeneity More than meningococci. Comparatively less.
21.    Grouping Strains characterized by auxotyping which recognizes reqiurements for specific nutrients. Serogroup is determined by its lipopolysaccharide capsular antigen.
22.    Normal Flora Not considered as normal flora. Many normal individuals may harbor Neisseria meningitidis in the upper respiratory tract
23.    Pathogen It is always a pathogen. It may or may not be pathogenic.
24.    Portal of Entry Genital Respiratory
25.    Site of Infection Primarily causing infection of the anogenital tract. Colonizes the upper respiratory tract as a commensal and occasionally invades to

cause systemic disease. 
26.    Virulence Factors Pili, IgA proteases and production of lipopolysaccharide endotoxin. LPS capsule, IgA protease and iron utilizationfrom transferrin.
27.    Related Conditions N. gonorrhoeae can also cause conjunctivitis, pharyngitis, proctitis or urethritis, prostatitis, and orchitis. Cause meningitis and other forms of meningococcal disease such as meningococcemia, a life-threatening sepsis.
28.    Specimens Transport swab of endocervix, urethra, rectum, pharynx, conjunctiva, blood, joint fluid, aspirates from skin lesions. Cerebrospinal fluid (CSF) and blood, swab skin lesions and nasopharynx.
29.    Presence in inflammatory exudates (pus) In larger proportions In less numbers
30.    Prevalence and Mortality N.gonorrhoeae infections have a high prevalence and low mortality. N. meningitidis infections have a low prevalence and high mortality.
31.    Superbug Considered as “superbug” Not considered as “superbug”
32.    Vaccines No Serogroup A, B, C, Y and W-135 meningococcal infections can be prevented by vaccines.

References

  1. Greenwood, D., Slack, R. C. B., Peutherer, J. F., & Duguid, J. P. (1992). Medical microbiology: A guide to microbial infections : pathogenesis, immunity, laboratory diagnosis, and control. Edinburgh: Churchill Livingstone.
  2. Sastry A.S. & Bhat S.K. (2016). Essentials of Medical Microbiology. New Delhi : Jaypee Brothers Medical Publishers.
  3. Parija S.C. (2012). Textbook of Microbiology & Immunology.(2 ed.). India: Elsevier India.
  4. https://microbiologyinfo.com/difference-between-neisseria-gonorrhoeae-and-neisseria-meningitides/
  5. https://www.jfmed.uniba.sk/fileadmin/jlf/Pracoviska/ustav-mikrobiologie-a-imunologie/NEISSERIA_AND_HAEMOPHILUS.pdf
  6. http://textbookofbacteriology.net/neisseria.html

About Author

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Sagar Aryal

Sagar Aryal is a microbiologist and a scientific blogger. He is doing his Ph.D. at the Central Department of Microbiology, Tribhuvan University, Kathmandu, Nepal. He was awarded the DAAD Research Grant to conduct part of his Ph.D. research work for two years (2019-2021) at Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Saarbrucken, Germany. Sagar is interested in research on actinobacteria, myxobacteria, and natural products. He is the Research Head of the Department of Natural Products, Kathmandu Research Institute for Biological Sciences (KRIBS), Lalitpur, Nepal. Sagar has more than ten years of experience in blogging, content writing, and SEO. Sagar was awarded the SfAM Communications Award 2015: Professional Communicator Category from the Society for Applied Microbiology (Now: Applied Microbiology International), Cambridge, United Kingdom (UK). Sagar is also the ASM Young Ambassador to Nepal for the American Society for Microbiology since 2023 onwards.

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