Fitch Ratings assigned an AA- underlying rating on the expected issuance of about $200 million in bonds on behalf of Florida-based BayCare Health System. Proceeds from the bonds will be used to refund about $154 million of outstanding auction-rate bonds issues in 2006 to provide $40 million to end a floating-to-fixed-rate swap on the 2006 bonds and to cover the cost of issuance, Fitch said in a release.