Bacon Wrapped Hamburgers

1/2 Cup shredded Cheddar cheese
1 Tablespoon grated Parmesan cheese
1 Small onion, chopped
1 Egg
1 Tablespoon ketchup
1 Tablespoon Worcestershire sauce
1/2 Teaspoon salt
1/8 Teaspoon pepper
1 Pound ground beef
6 Bacon slices
6 Hamburger buns, split

Preheat a grill for high heat.
In a large bowl, mix together the Cheddar cheese, Parmesan cheese, onion, egg, ketchup, Worcestershire sauce, salt and pepper. Crumble in the ground beef, and mix together by hand. Form into 6 patties, and wrap a slice of bacon around each one. Secure bacon with toothpicks.
Place patties on the grill, and cook for 5 minutes per side, or until well done. Remove toothpicks before serving on hamburger buns.