An organism from an eye wash of a patient with a cornea infection who had been wearing contact lenses for the past 2 years. what is the most likely agent?

An organism from an eye wash of a patient with a cornea infection who had been wearing contact lenses for the past 2 years. what is the most likely agent?

• A. Entamoeba histolytica
• B. Naegleria spp.
• C. Acanthamoeba spp.
• D. Trichomonas vaginalis

Answer: (C)

The scenario points to an organism that commonly causes severe keratitis in contact lens wearers exposed to contaminated water. Acanthamoeba spp. are free-living amoebae found in tap water, including eye wash, soil, and other environmental sources, and they can adhere to contact lenses or contaminated solutions. In a patient with a corneal infection who has worn contact lenses for years, Acanthamoeba keratitis is a classic pattern, often with disproportionate pain and a characteristic stromal ring infiltrate. Diagnosis is supported by finding trophozoites and cysts in corneal scrapings, and treatment can be challenging, typically using topical anti-amoebic agents. By contrast, Entamoeba histolytica mainly causes intestinal disease, Naegleria spp. are associated with fatal brain infection after nasal exposure, and Trichomonas vaginalis is a genital parasite, not a typical cause of eye infections. Therefore, the most likely agent is Acanthamoeba.

The scenario points to an organism that commonly causes severe keratitis in contact lens wearers exposed to contaminated water. Acanthamoeba spp. are free-living amoebae found in tap water, including eye wash, soil, and other environmental sources, and they can adhere to contact lenses or contaminated solutions. In a patient with a corneal infection who has worn contact lenses for years, Acanthamoeba keratitis is a classic pattern, often with disproportionate pain and a characteristic stromal ring infiltrate. Diagnosis is supported by finding trophozoites and cysts in corneal scrapings, and treatment can be challenging, typically using topical anti-amoebic agents. By contrast, Entamoeba histolytica mainly causes intestinal disease, Naegleria spp. are associated with fatal brain infection after nasal exposure, and Trichomonas vaginalis is a genital parasite, not a typical cause of eye infections. Therefore, the most likely agent is Acanthamoeba.