**Core Concept**
Panton-Valentine leukocidin (PVL) is a type of exotoxin produced by certain strains of Staphylococcus aureus, a bacterium commonly associated with skin and soft tissue infections. PVL is a bi-component toxin that causes lysis of leukocytes, leading to tissue damage and inflammation.

**Why the Correct Answer is Right**
PVL is produced by Staphylococcus aureus strains that carry the pvl gene, which encodes for the two subunits of the toxin. These subunits, LukS-PV and LukF-PV, work together to form a pore in the membrane of leukocytes, leading to cell lysis and the release of pro-inflammatory mediators. PVL is particularly associated with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because PVL is not produced by Streptococcus pyogenes, which is a different bacterium that produces a range of toxins, including streptolysins and erythrogenic toxins.

**Option B:** This option is incorrect because Coagulase-negative staphylococci, such as Staphylococcus epidermidis, do not produce PVL.

**Option C:** This option is incorrect because PVL is not produced by Escherichia coli, which is a gram-negative bacterium that produces a range of toxins, including Shiga toxin and hemolysin.

**Clinical Pearl / High-Yield Fact**
PVL-producing Staphylococcus aureus strains are often associated with severe skin and soft tissue infections, including necrotizing fasciitis and abscesses. These infections can be particularly challenging to treat due to the presence of antibiotic-resistant strains.

**Correct Answer:** C. Staphylococcus aureus