Resistant Streptococcus strain. Coloured transmission electron micrograph of a dividing Streptococcus pyogenes group A bacterium. This is the resistant strain implicated in the outbreak of necrotic fascitis in the UK which caused about a dozen fatalities. S. pyogenes is usually found in the nose and throat of healthy adults and is the most frequent cause of throat infections. The onset of necrotic fascitis is very rapid and may lead to death in a matter of hours. Large areas of fibrous connective tissue become necrotic with a gangrenous appearance and the infection is not stopped by common antibacterial drugs. Magnification: x44,000 at 6x4.5cm size.