Standard&Poor's Ratings Services affirmed its 'AA' long-term rating on Mayo Foundation's (Mayo) outstanding bonds. At the same time, Standard&Poor's lowered it rating to 'AA/A-1' from 'AA/A-1+' on the City of Rochester, Minn.'s $90 million health care facilities revenue bonds, series 2000A, issued for Mayo. In addition, the 'A-1+' short-term ratings on various issuers' health care facilities revenue bonds, issued for Mayo, were affirmed. The outlook is stable. The lowering of the short-term rating on the City of Rochester's $90 million series 2000A issue reflects a substitution of the liquidity provider to a standby bond purchase agreement (SBPA) provided by Morgan Stanley Bank from Mayo's own liquidity. The short-term ratings on certain bonds issued for Mayo (including