Cook bacon in a small Dutch oven until crisp; remove bacon, discarding drippings. Drain bacon on paper towels; crumble and set aside.

Place water, corn, celery, carrots, potatoes, onion, and reserved bacon in Dutch oven; bring to a boil. Cover and simmer 30 minutes.

Combine 1 cup milk and cornstarch in a small bowl, stirring well. Add cornstarch mixture, remaining milk, parsley, Worcestershire sauce, salt, oregano, and pepper to vegetables in Dutch oven; stir well. Bring to a boil; cook, uncovered, over high heat 1 minute, stirring constantly.

Stir in oysters; cover and simmer 15 minutes. Serve immediately in warm bowls.