The mechanism of antibiotics and how they work on bacteria is an important topic, especially on exams. Antibiotics are grouped together and work on a specific part of the bacteria. Some antibiotics such as penicillin, cephalosporin, and vancomycin work on the cell wall. Antibiotics, such as polymyxin, work in the cell membrane. Trimethoprim, sulfonamides and Bactrim will affect folic acid synthesis. Two antibiotics that affect Nucleic Acid Synthesis include: Ciprofloxacin and Metronidazole (flagyl)—which works on DNA gyrase, and rifampin, which works on the RNA polymerase.
Antibiotics that work on protein synthesis are Tetracyclines such as Doxycycline and Aminoglycosides —both of which are 30S. Another subunit of antibiotics that affect protein synthesis classified as 50s are Clindamycin, Macrolides such as Erythromycin, and Zyvox.
Dr. Nabil Ebraheim's Blog 