from sqlalchemy.text import text

# Create a database connection called "connection"...

q = text('USE :name')
connection.execute(q, name='DATABASE_NAME')

"You have an error in your SQL syntax; check the manual that
corresponds to your MySQL server version for the right syntax to use
near ''DATABASE_NAME'' at line 1") [SQL: u'USE %s;'] [parameters:
(u'DATABASE_NAME',)]