If the United States trustee has appointed an individual under
section 586(b) of title 28 to serve as standing trustee in cases under this subchapter, and if such individual qualifies as a trustee under
section 322 of this title, then that individual shall serve as trustee in any case under this subchapter. Otherwise, the United States trustee shall appoint one disinterested person to serve as trustee in the case or the United States trustee may serve as trustee in the case, as necessary.