[Bacterial flora of the external ear canal. 1. Cancer patients]

The bacterial flora of the external ear canal was investigated in a group of 64 patients with head and neck cancer, to observe why otitis externa frequently occurs in cancer patients. Staphylococcus epidermidis (48.5%), Pseudomonas sp. (18.8%), and Flavobacterium sp. (16.8%) were the prominent isolates from ear samples, and Gram-negative organisms which rarely existed in normal canal, were found to be markedly increased (59.4%). Moreover, about half of all non-sterile ear canals were found to have more than one Gram-negative flora. We have concluded that cancer patients probably suffer from external otitis more frequently because of enhanced colonization by Gram-negative pathogens.