What is the Difference Between Neisseria Gonorrhoeae and Neisseria Meningitidis

The main difference between Neisseria Gonorrhoeae and Neisseria Meningitidis is that N. gonorrhoeae causes gonorrhea whereas N. meningitidis causes cerebrospinal meningitis.

N. gonorrhoeae and N. meningitidis are two types of closely-related organisms with different pathogenicity. Both are Gram-negative bacteria.

Key Areas Covered

1. What is Neisseria Gonorrhoeae
     – Definition, Characteristics, Importance
2. What is Neisseria Meningitidis
     – Definition, Characteristics, Importance
3. Similarities Between Neisseria Gonorrhoeae and Neisseria Meningitidis
     – Outline of Common Features
4. Difference Between Neisseria Gonorrhoeae and Neisseria Meningitidis
     – Comparison of Key Differences

Key Terms

Neisseria Gonorrhoeae, Neisseria Meningitidis

What is Neisseria Gonorrhoeae

N. gonorrhoeae is a gonococcus bacterium that is a species of Gram-negative diplococci. The main importance of the bacterium is that it causes the sexually-transmitting disease gonorrhoea. Generally, the sexual transmission of N. gonorrhoeae occurs through oral, anal, and vaginal sex. However, barrier protections can prevent the transmission of the bacterium sexually. Other than the sexual transmission of N. gonorrhoeae, it infects the genitals, eyes, and throat. In general, the bacterium causes asymptomatic infections in both males and females. When untreated, infections can spread to the rest of the body.

Figure 1: Neisseria gonorrhoeae

Furthermore, untreated infections may cause pelvic inflammatory disease in females. Scarring in the process can cause infertility. In addition, it causes other forms of gonococcal diseases, including septic arthritis, disseminated gonococcemia, and gonococcal ophthalmia neonatorum. N. gonorrhoeae is an aerobic bacterium that is oxidase positive. Apart from that, they can grow inside neutrophils, and therefore they can survive phagocytosis. The diagnosis of N. gonorrhoeae is by Gram-staining, culturing, nucleic acid tests, PCR, urethral swab, urine sample, and cervical swab.  

What is Neisseria Meningitidis

N. meningitidis is a Gram-negative bacterium that causes meningitis and other forms of meningococcal disease, including meningococcemia and sepsis, which is life-threatening. The shape of the bacteria is a coccus. N. meningitidis is a diplococcus bacterium due to its tendency to form pairs. It is the main cause of bacterial meningitis in children as well as adults. Usually, 10% of adults carry N. meningitis bacterium in the nasopharynx. N. meningitis is an exclusively human pathogen in children and young adults. It also causes developmental impairments and death in 10% of infected cases.

Figure 2: Neisseria meningitidis

Moreover, the spreading of N. meningitidis occurs through saliva and respiratory secretions. It occurs during coughing, kissing, sneezing, and chewing. In addition, the transmission of the N. meningitidis bacteria occurs through oral sex. Usually, it forms urethritis in men. This bacterium infects host cells by sticking them with pili. Apart from that, surface-exposed proteins such as Opa and Opc and several virulence factors also help in the infection of the host cell by the bacterium.     

Similarities Between Neisseria Gonorrhoeae and Neisseria Meningitidis

• Gonorrhoeae and N. meningitidis are two types of closely-related bacteria.
• Both are Gram-negative bacteria.

Difference Between Neisseria Gonorrhoeae and Neisseria Meningitidis

Definition

N. gonorrhoeae refers to a bacterial pathogen responsible for gonorrhea, while N. meningitidis refers to the bacteria that causes the illness cerebrospinal meningitis.

Morphology

N. gonorrhoeae is kidney-shaped, and opposing ends are concave, while N. meningitidis is semicircular with opposing ends.

Capsule

N. gonorrhoeae does not contain a capsule, while N. meningitidis contains a capsule.

Colony Morphology

Moreover, N. gonorrhoeae forms a smooth, round, uniform, and moist colonies that are brown in color while N. meningitidis forms large, brown-color colonies.

Maltose Fermentation

N. gonorrhoeae does not undergo maltose fermentation, while N. meningitidis undergoes maltose fermentation.

Pathogenesis

N. gonorrhoeae causes gonorrhoea, but N. meningitidis causes cerebrospinal meningitis.

Conclusion                                                                                                

In brief, N. gonorrhoeae and N. meningitidis are two types of closely related bacteria. Generally, N. gonorrhoeae is a bacterial pathogen that causes gonorrhea. N. gonorrhoeae is a kidney-shaped bacterium that has opposing ends. It also contains a capsule. It forms a smooth, round, uniform, and moist colonies that are brown in color. In contrast, N. meningitidis is a bacterial pathogen that causes cerebrospinal meningitis. In general, the bacterium is semicircular and has opposing ends. Also, it forms large, brown-color colonies. However, the main difference between N. gonorrhoeae and N. meningitidis is the type of disease they cause.                                                   

References:                

1. Wikimedia Foundation. (2022, December 6). Neisseria gonorrhoeae. Wikipedia. Retrieved December 23, 2022
2. Wikimedia Foundation. (2022, October 22). Neisseria meningitidis. Wikipedia. Retrieved December 23, 2022

Image Courtesy:

1. “cal urethritis PHIL 4085 lores” By Nephron – Own work (Public Domain) via Commons Wikimedia
2. “Neisseria meningitidis Charles-Orszag 2018” By Myron G. Schultz – Own Work (CC BY-SA 4.0) via Commons Wikimedia