The Opa gene is used to identify this endotoxin-producing bacterium that grows well in the high- CO₂ conditions inside phagocytes.

Verified step by step guidance

1. Identify the bacterium that is known to produce endotoxins and thrives in high-CO₂ environments.
2. Consider the role of the Opa gene in bacterial identification and its association with specific bacteria.
3. Recall that the Opa gene is associated with Neisseria species, which are known for their ability to survive in phagocytes.
4. Understand that Neisseria gonorrhoeae and Neisseria meningitidis are two species that possess the Opa gene and can produce endotoxins.
5. Conclude that the bacterium in question is likely Neisseria gonorrhoeae or Neisseria meningitidis, both of which fit the given conditions.

Key Concepts

Opa Gene

The Opa gene is a virulence factor found in certain strains of Neisseria gonorrhoeae and Neisseria meningitidis. It encodes for outer membrane proteins that facilitate adherence to host cells and play a role in immune evasion. Understanding the function of the Opa gene is crucial for identifying these bacteria and studying their pathogenic mechanisms.

Endotoxin

Endotoxins are components of the outer membrane of Gram-negative bacteria, primarily lipopolysaccharides (LPS). They are released when the bacteria die and can trigger strong immune responses in the host, leading to symptoms such as fever and inflammation. Recognizing the role of endotoxins is essential for understanding the pathogenicity of bacteria like Neisseria.

Phagocyte Environment

Phagocytes, such as macrophages and neutrophils, are immune cells that engulf and digest pathogens. Some bacteria, like Neisseria, can thrive in the high-CO₂ environment within phagocytes, which can enhance their survival and replication. This adaptation is significant for understanding how certain pathogens evade the immune response and persist in the host.