A 65-year-old man with a history of rheumatic heart disease is being evaluated in preparation for his first screening colonoscopy. He is otherwise at average risk for colorectal cancer and has been told by his dentist that he needs antibiotics before all surgical procedures. Review of his medical record reveals a recent echocardiogram demonstrating mild thickening of the mitral valve leaflets and mild mitral regurgitation. He has no history of chronic kidney disease. The most appropriate recommendation is that: