What is Optimal Post-operative Prophylactic Therapy in Irradiated Breasts Undergoing Repeat Surgery

This study looks at the best antibiotic to use before repeat breast surgery in women who have previously had both breast surgery and radiation therapy to the same breast. Prior radiation increases the risk of infection with repeat surgery, and researchers want to find out which antibiotic (or combination) works best to prevent post-operative infections. **You may be eligible if...** - You are a woman over 18 years old - You have previously had breast surgery AND radiation therapy to the same breast - You now need another breast surgery on that same breast **You may NOT be eligible if...** - You are currently taking antibiotics for another reason - You are allergic to trimethoprim or sulfonamides - You have a history of drug-induced immune thrombocytopenia (low platelets from certain antibiotics) - You have severe liver or kidney disease - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.