Serratia marcescens Canaliculitis: A Case Report of Uncommon Etiology

A 66-year-old female patient presented with chronic medial eyelid swelling and discharge of the right eye. She was initially treated with tobramycin eye drops and oral amoxicillin-clavulanic acid. However, the persistence of signs and symptoms accompanied by grainy punctal discharge on follow-up prompted a diagnosis of lacrimal canaliculitis. She underwent punctum-sparing right superior and inferior canaliculotomy under local anesthesia and completed topical antibiotic treatment with moxifloxacin. Serial follow-up examinations showed complete resolution of swelling, discharge, and epiphora. Microscopic examination of the lacrimal concretions showed the presence of <i>Serratia marcescens</i>, an unusual cause of canaliculitis. As a microorganism of nosocomial and opportunistic origin, it is commonly found in medical equipment, urine-collecting basins, and even tap water. Although extremely rare, <i>Serratia marcescens</i> should be considered in chronic lacrimal canaliculitis presenting with concretions.