[Bacterial flora of the external ear canal. 2. Effect of irradiation]

A group of 34 patients with nasopharyngeal cancer was studied to observe the influence of the radiation effect on the bacterial flora of the external ear canal. The effects were observed before and after radiation therapy. The Gram-positive aerobes, especially the Staphylococcus epidermidis, were found to have decreased (57.1% to 37.7%). Though there was a slight increase of the Gram-negative aerobes (44.6% to 50.8%), it was not statistically significant. We concluded that the higher incidence of otitis externa induced by irradiation is due to the local radiation reaction, but not the shifted colonization of the potentially pathologic flora.