Fluroquinolone mechanism of action in gram positive organism is by ?
**Core Concept**
Fluoroquinolones are a class of antibiotics that exert their bactericidal effect by inhibiting bacterial DNA replication. In gram-positive organisms, fluoroquinolones target the bacterial enzyme DNA gyrase and topoisomerase IV.
**Why the Correct Answer is Right**
Fluoroquinolones bind to the active site of DNA gyrase and topoisomerase IV, preventing the enzymes from catalyzing the unwinding of DNA. This leads to the accumulation of double-strand breaks in the bacterial DNA, ultimately causing cell death. The mechanism of action is similar to that of other fluoroquinolones, such as ciprofloxacin and levofloxacin, which also inhibit DNA gyrase and topoisomerase IV in gram-positive organisms.
**Why Each Wrong Option is Incorrect**
* **Option A:** Fluoroquinolones do not inhibit cell wall synthesis, which is the mechanism of action of beta-lactam antibiotics like penicillin.
* **Option B:** Fluoroquinolones do not target the bacterial protein synthesis, which is the mechanism of action of antibiotics like tetracycline.
* **Option C:** Fluoroquinolones do not inhibit the bacterial electron transport chain, which is the mechanism of action of antibiotics like metronidazole.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that fluoroquinolones can cause phototoxicity and should be used with caution in patients with a history of skin sensitivity or porphyria.
**Correct Answer: C. Inhibiting DNA gyrase and topoisomerase IV.**