A 65-year-old man with a long history of diabetes mellitus was hospitalized for treatment of an ulcer, which had been present on his left great toe for several months. Left sided below knee amputation was performed because of the inability multiple courses of oral antibiotics to resolve the ulcer, On the first postoperative day, he developed fever which worsened by day 2. His amputation stump was mottled with many areas of purplish discoloration, and the most distal areas were quite obviously necrotic. Crepitus was palpable up to his patella. An X-ray of the left lower extremity was done. What is the likely pathogen?
X-ray of the left lower extremity shows gas in the soft tissues, extending beyond the knee to the area of the distal femur This patient had Clostridium perfringens gas gangrene It is one of the dreaded complications that may follow lower extremity amputation in diabetics. * The resulting dead or dying tissue has very low oxygen tension, which greatly ours the growth of anaerobes. If the amputation is insufficient, it may leave behind tissue whose blood supply is compromised to the point that oxygen tension in the remaining stump ours the growth of anaerobes. The elaboration, by C. perfringens, of large amounts of gas that are not absorbed by the tissues allows the clostridial organisms to spread along fascial planes, which are separated by the pressure of the gas as the clostridia grows. Thus, gas production acts as a "virulence factor," which makes this organism quite ferocious.
Escherichia coli
Actinomyces israelii
Clostridium perfringens
Staphylococcus aureus
Integrated QBank