ampicillin (amoxicillin/clavulanate) and Bactrim (sulfamethoxazole and trimethoprim) are antibiotics used to treat a wide variety of bacterial infections. Augmentin and Bactrim are different types of antibiotics. Augmentin is a combination penicillin-type antibiotic and a beta-lactamase inhibitor and Bactrim is a combination of an anti-bacterial sulfonamide (a "sulfa" drug) and a folic acid inhibitor.