The Hidden Dangers of Summer Swim: Understanding Otitis Externa Risks in Freshwater Lakes Infested with Pseudomonas aeruginosa

Abstract

OBJECTIVE–To ascertain if a surge in otitis externa was linked to swimming in freshwater recreational lakes and to confirm if the epidemic was attributable to Pseudomonas aeruginosa present in the water. DESIGN–Matched case-control investigation. SETTING–The Achterhoek region, the Netherlands. SUBJECTS–98 instances of otitis externa and 149 matched controls according to age, gender, and residence. MAIN OUTCOME MEASURES–Odds ratios regarding type of swimming water and swimming frequency; the detection of P aeruginosa in ear swabs and freshwater lakes. RESULTS–Otitis externa exhibited a significant correlation with swimming in recreational freshwater lakes during the prior two weeks (odds ratio 15.5 (95% confidence interval) 4.9 to 49.2) compared to non-swimmers. The risk heightened with the number of days spent swimming, and individuals with recurrent ear issues had a markedly increased risk. The lakes adhered to the Dutch bathing water regulations and those established by the European Commission for fecal contamination in the summer of 1994; however, P aeruginosa was isolated from all of them, as well as from ear swabs of 78 (83%) of the affected individuals and 3 (4%) of the controls. CONCLUSIONS–Even if existing bathing water criteria are satisfied, swimming can entail a significant risk of otitis externa due to exposure to P aeruginosa. Individuals with recurrent ear conditions should exercise caution when swimming in waters harboring P aeruginosa.