Sulfadiazine is a sulfonamide antibiotic that inhibits the synthesis of bacterial cell walls by binding to the enzyme beta-lactamase. Sulfadiazine binds to beta-lactamase enzyme and prevents it from breaking down and destroying penicillin molecules and other beta-lactam antibiotics. This mechanism prevents the production of bacterial cell walls and as a result, leads to cell death. Sulfonamides are used in combination with other antibiotics.