Progressive bacterial synergistic gangrene: causes, symptoms, diagnosis, treatment, prognosis, and prevention

Progressive bacterial synergistic gangrene, also known as Meleney's synergistic gangrene, Meleney's postoperative progressive synergistic gangrene, or chronic undermining burrowing ulcer, is a subcutaneous tissue infection caused by microaerobic nonhemolytic streptococcus and anaerobic streptococcus, with slow progression, with severe soft tissue necrosis.


Causes

The pathogens are similar to those of necrotizing fasciitis and are composed of various bacteria. Microaerobic nonhemolytic streptococcus is often found around the infected focus, and Staphylococcus aureus, Bacillus proteus, Enterobacteria, Pseudomonas aeruginosa, and Clostridium can be isolated in the central necrotic area.

This disease often occurs near the incision of abdominal or chest surgery, especially the site with indwelling suture, incision of intraabdominal abscess and empyema drainage, and stoma for colostomy or ileostomy, as well as microtrauma.

Pathogenesis

Bacterial synergistic gangrene is a slow-progressive infection, with a development of only 1 - 2cm in 7 - 10 days. Histopathology reveals chronic suppurative necrotizing inflammation with obvious eosinophilic infiltration.

Cutaneous, subcutaneous, fascial, and muscular extensive dissolution and coagulative necrosis are present. A large number of Gram-positive cocci and various bacilli can be seen in the necrotic area. Superficial necrosis develops gradually down to the deep, and necrosis can be seen in the skin, subcutaneous tissues, deep fascia, muscle, interosseous membrane, and bones.

Some small blood vessel walls around the necrotic lesion reveal inflammatory cell infiltration and hyperplasia, and some lumens are narrow or occluded. Circulatory embarrassment caused by microcirculatory stasis and embolism in the tissues is visible.

Necrotic focus is surrounded by dense lymphocytes, plasma cells, mononuclear cells, and a large number of eosinophils. The infiltrating inflammatory cells can even be dominant in some areas.


Signs and Symptoms

Several days to several weeks after surgery, a small red and swollen induration appears near the wound, developing into a grayish red inflammatory infiltrating area, with purple center.

Severe pain and tenderness in the purple area is a local characteristic of this disease. The necrotizing induration gradually evolves into an ulcer, with undermined edges. The ulcer is surrounded by purplish red gangrene, with serous secretions.

The ulcer expands slowly, and is surrounded by the necrotic skin. The necrotic skin is surrounded by a purple annular zone that is surrounded by red halos. Discrete satellite ulcers, multiple sinus tracts, and tenderness are present. The ulcer is also known as Meleney's ulcer.

Systemic symptoms are mild.


Diagnosis

On the basis of a history of surgery, typical skin lesions such as Meleney's ulcer, and results of bacterial isolation and culture, the disease can be diagnosed.


Treatment

The disease is a mixed infection of multiple bacteria, and there is a strong synergistic effect between the pathogens, so it is difficult to treat.

Extensive debridement is required. After the granulation tissue grows, skin grafting can be considered.

Antibiotics can be selected according to the results of bacterial culture and drug susceptibility test. Penicillin may be used before the results are reported. It has been reported that imipenem and cilastatin sodium have a significant effect in the treatment of this disease.

Oleum zinci oxidi can be applied to the periphery of the ulcer to protect the surrounding healthy skin.


Prognosis

Bacterial synergistic gangrene mainly invades subcutaneous soft tissue, and the disease develops slowly. After active and comprehensive treatment, the body functions are not affected.


Prevention

Contaminated wounds should be cleaned and debrided as much as possible during the operation, and antibiotics should be used prophylactically after surgery.