: Question #17 A 35-year-old man comes to the emergency room for severe left leg pain several hours after injuring himself on a gardening tool. His temperature is 39°C (102.2°F) and his pulse is 105/min. Physical examination of the left leg shows a small laceration on the ankle surrounded by dusky skin and overlying bulla extending to the posterior thigh. There is a crackling sound when the skin is palpated. Surgical exploration shows necrosis of the gastrocnemius muscles and surrounding tissues. Tissue culture shows anaerobic gram-positive rods and a double zone of hemolysis on blood agar. Which of the following best describes the mechanism of cellular damage caused by the responsible pathogen? Answer Image A Lipopolysaccharide-induced complement and macrophage activation B Degradation of cell membranes by phospholipase с Increase of intracellular CAMP by adenylate cyclase D Inactivation of 60s ribosome subunit by N-glycosidase E Inactivation of elongation factor by ribosyltransferase F Inhibition of neurotransmitter release by protease