Metronidazole is converted to reduction products that interact w/ DNA to cause destruction of helical DNA structure and strand leading to a protein synthesis inhibition and cell death in susceptible organisms. It is active against most anaerobic protozoa, some gm+ve, gm-ve and facultative anaerobes. Nystatin, a polyene antifungal, binds to ergosterol in the fungal cell membrane. This binding affects the cell wall permeability allowing leakage of cellular contents. Polymyxin B disrupts the bacterial cytoplasmic membrane of mostly gm-ve organisms allowing leakage of intracellular constituents by binding to membrane phospholipids. Neomycin is an aminoglycoside antibiotic. It binds to 30S ribosomal subunits...