Okay, let's tackle this question. The question is about an enzyme produced by streptococci that turns thick pus into a thinner consistency. Hmm, I remember that some bacteria produce enzymes to help them spread or survive in the host. Streptococcus species are known for various enzymes like streptokinase, streptodornase, and hyaluronidase.

Thick pus is usually due to fibrin. If there's an enzyme that breaks down fibrin, that would make the pus thinner. Streptokinase is a clot-busting enzyme, right? It activates plasminogen to plasmin, which digests fibrin clots. So maybe streptokinase is the answer here.

Wait, streptodornase breaks down DNA in pus, which also contributes to thinning. Oh, but the question mentions "streptococci" specifically. Let me think. Streptococcus pyogenes (Group A) produces both streptokinase and streptodornase. But which one is responsible for liquefying pus? Streptokinase acts on fibrin, while streptodornase acts on DNA. Pus has a lot of DNA from dead white blood cells, so breaking down DNA would make the pus less viscous. So maybe streptodornase is the enzyme here.

Wait, but the question says "thick pus of streptococci is converted thin by enzyme." So if the pus is thick because of DNA, then the enzyme that breaks down DNA (streptodornase) would make it thin. Alternatively, if it's due to fibrin, then streptokinase. I need to recall which enzyme is responsible for this specific effect.

Another angle: when you have a streptococcal infection, the pus tends to be more liquid because of these enzymes. Streptokinase is more about dissolving blood clots, while streptodornase (deoxyribonuclease) breaks down nucleic acids. So in the context of pus, which is rich in DNA, streptodornase would make it thin. Therefore, the correct answer should be streptodornase.

But wait, the options weren't provided in the original question, so I need to make sure. The user didn't list the options, but the correct answer is probably streptodornase. Let me confirm. Yes, streptodornase is the enzyme that degrades DNA in pus, making it less viscous. So the answer should be streptodornase, which is also known as deoxyribonuclease (DNase).

**Core Concept**
Streptococcal enzymes like streptokinase and streptodornase (DNase) modify host tissues to evade immune defenses. **Streptodornase** specifically degrades extracellular DNA in pus, reducing viscosity and aiding bacterial spread.

**Why the Correct Answer is Right**
**Streptodornase (DNase)** is a deoxyribonuclease produced by *Streptococcus pyogenes*. It hydrolyzes DNA from dead leukocytes in pus, breaking down the viscous DNA matrix. This liquefies pus, facilitating bacterial dissemination and reducing host immune entrapment. Unlike streptokinase (which targets fibr

✓ Correct Answer: A. DNAase