The mechanism of action of quinolones antimicrobials is:

Correct Answer: B

Rationale: Quinolones (e.g., ciprofloxacin) inhibit DNA gyrase, disrupting bacterial DNA replication.

Correct Answer: A

Rationale: First-generation cephalosporins (e.g., cefazolin) are relatively beta-lactamase resistant, unlike later generations with broader spectra.

Correct Answer: C

Rationale: Gentamicin causes nephrotoxicity and ototoxicity, not hemolytic anemia, which is not a typical side effect.

Correct Answer: D

Rationale: Ciprofloxacin is a systemic antibiotic, not a urinary antiseptic like the others, which act locally in the urinary tract.

Correct Answer: C

Rationale: Acyclovir is an antiviral drug effective against herpes viruses, unlike the others which are antibacterial or antiparasitic.