Which type of infection is associated with opportunistic pathogens?

Opportunistic pathogens are microorganisms that typically do not cause disease in healthy individuals with a fully functioning immune system. Instead, they take advantage of certain conditions that compromise the immune system, making it easier for them to establish an infection. This phenomenon is particularly notable in immunocompromised individuals, such as those with HIV/AIDS, cancer patients undergoing chemotherapy, patients on immunosuppressive drugs, or individuals with genetic immunodeficiencies.

In these cases, the normally benign or low-virulence organisms can cause serious infections due to the weakened immune defenses of the host. Common opportunistic infections include those caused by organisms like Candida species, Pneumocystis jirovecii, and certain strains of Escherichia coli, which are usually harmless in healthy individuals but can lead to severe disease in those who are vulnerable.

The other answer choices do not align with the concept of opportunistic infections. Infections occurring in healthy individuals or under normal circumstances do not typically involve opportunistic pathogens, as those infections are generally caused by primary pathogens that can affect anyone. Additionally, while opportunistic infections can be serious and even fatal, not all are universally fatal; many can be treated successfully if identified and managed promptly in the appropriate clinical context.