Neisseria

Definition

Neisseria is a genus of Gram-negative, oxidase-positive diplococci bacteria that are commonly found as part of the normal microbiota of the human respiratory tract. These bacteria are important in the context of the anatomy and normal microbiota of the respiratory system.

5 Must Know Facts For Your Next Test

1. Neisseria species are found in the upper respiratory tract, particularly in the nasopharynx, as part of the normal microbiota.
2. The most well-known Neisseria species are Neisseria meningitidis, which can cause meningitis, and Neisseria gonorrhoeae, which causes the sexually transmitted infection gonorrhea.
3. Neisseria species are typically harmless commensals in the respiratory tract, but they can opportunistically cause infections in immunocompromised individuals.
4. These bacteria are oxidase-positive, which means they possess the enzyme cytochrome c oxidase, an important component of the respiratory electron transport chain.
5. Neisseria species are diplococci, meaning they typically appear in pairs, with the cells flattened on the adjacent sides, forming a characteristic coffee bean-like shape.

Review Questions

• Describe the role of Neisseria in the normal microbiota of the respiratory tract.
  • Neisseria species are commonly found as part of the normal microbiota in the upper respiratory tract, particularly in the nasopharynx. As commensal bacteria, they typically do not cause harm but rather play a role in maintaining a healthy respiratory environment. However, under certain conditions, such as in immunocompromised individuals, Neisseria can opportunistically cause infections.
• Explain the significance of Neisseria being oxidase-positive and diplococci in the context of the respiratory tract.
  • The oxidase-positive nature of Neisseria species indicates the presence of the enzyme cytochrome c oxidase, which is an important component of the respiratory electron transport chain. This suggests that Neisseria is well-adapted to the respiratory environment and can effectively participate in cellular respiration. Additionally, the characteristic diplococci shape of Neisseria, with the cells forming pairs, is a distinctive feature that helps identify and differentiate these bacteria within the respiratory microbiota.
• Analyze the potential impact of Neisseria species on respiratory health and disease, considering their role as both commensal and pathogenic bacteria.
  • Neisseria species are generally considered commensal bacteria that are part of the normal microbiota in the respiratory tract. However, some Neisseria species, such as Neisseria meningitidis, can opportunistically cause serious infections, such as meningitis, in immunocompromised individuals. This highlights the delicate balance between Neisseria's role as a harmless commensal and its potential to become a pathogen. Understanding the factors that can shift this balance, as well as the mechanisms by which Neisseria can cause disease, is crucial for maintaining respiratory health and developing effective strategies to prevent and treat Neisseria-related respiratory infections.

Related terms

Oxidase-positive: A characteristic of certain bacteria that indicates the presence of cytochrome c oxidase, an enzyme involved in the respiratory electron transport chain.

Diplococci:

Bacteria that typically occur in pairs, with the cells flattened on the adjacent sides, forming a distinctive coffee bean-like shape.

Normal Microbiota: The community of microorganisms that naturally inhabit a specific body site, such as the respiratory tract, and play a role in maintaining health.