Ear infections with Shewanella alga: a bacteriologic, clinical and epidemiologic study of 67 cases

OBJECTIVE: To present bacteriologic and clinical data on 67 patients from the island of Funen, Denmark, with Shewanella alga, a bacterium rarely seen in Scandinavia, isolated from ear swabs. Included in the study is an examination of the occurrence of S. alga in sea water around the island. METHODS: Bacteriologic examination and antibiotic susceptibility testing of 67 clinical isolates, 11 sea-water isolates and two reference strains were conducted. Clinical information was obtained from the referring physicians. RESULTS: During 6 months S. alga was isolated from 67 patients, in 33 cases in pure culture. Seventy per cent of the patients were children between 3 and 15 years old who had clinical symptoms of acute or chronic otitis media. Previous ear disease was common (76%). Most of the cases (85%) occurred in August or September, and 47 of 55 patients reported contact with sea water shortly before symptoms developed. From seven of the patients, S. alga was isolated more than once. The species was also isolated from five of 10 bathing areas around the island of Funen. CONCLUSIONS: The patients were probably infected with S. alga during sea-water bathing in the unusually warm summer of 1994. Infections with marine bacteria are possible in countries with a temperate climate; patients with previous ear disease are at special risk.