A case of bacterial keratitis caused by multi-drug-resistant Shewanella algae without marine exposure

Shewanella are Gram-negative rods and marine pathogens. Here, we report a case of bacterial keratitis caused by Shewanella algae without marine exposure. A 66-year-old man with suspected pneumonia was sent to the emergency department from a nursing hospital. He had been in there for 2 years in a vegetative state and could not close his eyes voluntarily. Neither the patient nor his family had experienced any marine exposure. Keratitis was suspected in his right eye. Gram-negative rods grew from swab culture and identified as S. algae by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and 16S rRNA sequencing. The patient was treated with topical tobramycin, moxifloxacin and ofloxacin as well as steroids for 14 days, and the keratitis improved. S. algae is a rare human pathogen, and most human infections involve marine exposure. This is the second report of bacterial keratitis caused by S. algae worldwide and the first in Asia.