What is an opportunistic (super) infection?

• A. Infection that occurs after normal flora are destroyed
• B. An infection caused by viruses
• C. An infection that is always contagious
• D. An infection that resolves without treatment

Answer: (A)

An opportunistic infection happens when the body's defenses are weakened or its normal microbial barriers are disrupted, allowing organisms that normally coexist harmlessly or are kept in check to cause disease. A common trigger is destroying the normal flora with antibiotics, which creates an environment where fungi like Candida or bacteria such as Clostridioides difficile can overgrow or invade. This idea—that disease arises because the host’s defenses or microbial balance have been altered—best matches the scenario described. It’s not defined by being a viral infection, nor by contagiousness, and it isn’t about resolving without treatment.