A bacteriological study of microbial flora in the ear canal of divers and swimmers revealed a direct correlation between degree of exposure of ears to water and type of bacterial flora resident in the ear canal. Each diver began the dive with a Gram-positive bacterial flora. This flora was replaced by a primarily Gram-negative bacterial population shortly after immersion.
Otitis externa occurred in all cases where moisture predisposed such change in microbial flora, ie, 100% of the divers, 16% of the swimmers, and no nonswimmers. No single species of bacteria was isolated from all cases of disease. However, Pseudomonas aeruginosa was most often associated with otitis externa. Changes in microflora during prolonged water exposure and effects of a therapeutically assisted return to normal are described.
Wright DN, Alexander JM. Effect of Water on the Bacterial Flora of Swimmers' Ears. Arch Otolaryngol. 1974;99(1):15–18. doi:10.1001/archotol.1974.00780030019003