Necrotising Fasciitis (often referred to in the popular media as ‘flesh-eating killer-bug’ infection). A potentially lethal infection caused by the gram-positive (see GRAM'S STAIN) bacterium Streptococcus pyogenes, which has the property of producing dangerous exotoxins. The infection, which starts with CELLULITIS of FASCIA under the SKIN, may spread very rapidly, destroying tissue as it spreads. Urgent antibiotic treatment may check the infection, but major surgery is sometimes required to remove the damaged skin and underlying tissues such as muscle, in order to prevent death (see STREPTOCOCCUS).