BUZZ-Mediclinic: Down as Swiss, UAE margins under pressure
** Hospital operator Mediclinic 2nd-top faller on FTSE 100
** Swiss unit's H1 margin falls to 17.4 pct from 18.6 pct last year; Lower Swiss margin reflects lower patient volumes, ongoing insurance mix change, co says. Revenue per bed in Swiss unit down 1.3 pct
** Co reports lower H1 EBITDA margins of 8.5 pct from 11 pct last year for Middle East unit. Lowers sales guidance for South Africa
** Switzerland, UAE margins miss Jefferies' estimates, reiterates "underperform" rating on stock
** Stock biggest loser on STOXX 600 healthcare index (RM (LSE: RM.L - news) :sanjeeban.sarkar.thomsonreuters.com@reuters.net)