Each of the following statements concerning Treponema is correct EXCEPT:

  •  Patients infected with T. pallidum produce antibodies that react with beef heart cardiolipin.
  •  T. pallidum cannot be grown on conventional laboratory media.
  •  Treponemes are members of the normal flora of the human oropharynx.
  •  T. pallidum produces an exotoxin that stimulates adenylate cyclase.