Bond and oath.) Before entering upon the performance of his duties, every public administrator and every public guardian shall take and file in the court an oath or affirmation that he will support the Constitution of the United States and the Constitution of the State of Illinois and will faithfully discharge the duties of his office and shall enter into a bond payable to the people of the State of Illinois in a sum of not less than $5,000 with security as provided by this Act and approved by the court of the county in which he is appointed, conditioned that he will faithfully discharge the duties of his office. The court may from time to time require additional security of the public administrator or guardian and may require him to give the usual bond required of representatives of estates of decedents, or persons with disabilities in other cases. In default of his giving bond within 60 days after receiving his commission or of his giving additional security within 60 days after being ordered by the court to do so, his office is deemed vacant and upon certificate of a judge of the court of that fact the Governor or the Circuit Court shall fill the vacancy.