<prompt> All of the following antibacterial agents acts by inhibiting cell wall synthesis, except -CarbapenemsMonobactamsCephamycinsNitrofurantoin  <response>: Ans. is d i.e., Nitrofurantoin Nitrofurantoin acts by generation of highly reactive intermediates which damage DNA. It does not inhibit cell wall synthesis. Drugs inhibiting cell wall synthesis - beta-lactarn antibiotics Penicillin, Cephalosporins, monobactoms, Carbapenems, Cycloserine, bacitracin, vancomycin, fosfomycin. o Cause leakage from cell membrane - Polypeptides Polymyxins, Colistin, tyrothricin, Polyenes Amphotericin B, Nystatin, Hamycin, Azoles Ketoconazole, fluconazole, intraconazole o Inhibit protein synthesis - Tetracyclines, Chloramphenicol, Erythromycin, Clindamycin, Linezolid. o Cause misreading of m-RNA code and affect permeability- Aminoglycosides. Inhibit DNA gyrase - Nalidixic acid and fluoroquinolones. Interfere with DNA function - Rifampin, metronidazole. Interfere with DNA synthesis - Acyclovir, zidovudin. o Interfere with intermediary metabolism - Sulfonamide, Sulfones, PAS, trimethoprim, Pyrimethamine, Ethambutol. 