The bacteriology of infected malignant ulcers.

Infected ulcerated malignant tumours are often foul smelling and covered with necrotic tissue. We have studied 70 patients with infected ulcers; 30 of the underlying lesions in these patients were carcinoma of the breast, and 19 were a variety of skin cancers. Anaerobes were the predominant organisms isolated from individual ulcers. Of the 179 anaerobes isolated, 37 were Bacteroides asaccharolyticus, 31 each were B melaninogenicus and anaerobic streptococci, 29 B fragilis, and 17 B ureolyticus. Among the facultative organisms Escherichia coli was the commonest and was isolated mainly from patients with carcinoma of the breast. Most infections were mixed, yielding both anaerobes and aerobes and this made interpretation of the role of individual pathogens difficult to assess.