All of the following antibacterial agents acts by inhibiting cell wall synthesis, except -

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.