Pythium insidiosum Keratitis in Israel

Abstract

This is the first reported case of culture-proven, contact lens-related Pythium keratitis originating from Israel. Pythium is a fungus-like, aquatic oomycete found in tropical climates. Human pythiosis is uncommon but associated with high morbidity. Case reports describe surgical cure of Pythium keratitis, but this case recurred despite two penetrating keratoplasties and maximal antifungal therapy. In cases of presumed fungal keratitis that do not respond to antifungals, the fungus should be sent for speciation because early surgical intervention is the only means to save the eye in ocular pythiosis.

Imported Pythium insidiosum Keratitis After a Swim in Thailand by a Contact Lens-Wearing Traveler

“…17 In most cases, patients have a history of being recently exposed to wet environments (wastewater, rice paddies, swimming pool, tap water, or river) or farming occupations, which was shown in a series of 11 cases of Pythium keratitis in which 91% patients were farmers. 10 Recently, Thanathanee and others 11 reported an outbreak of four consecutive cases of ocular pythiosis during the rainy season in Thailand; all of them had a history of fungal keratitis after being exposed to contaminated water (wastewater, rice field [N = 2], or contaminated rainwater).…”

“…In total, 45 cases of Pythium keratitis have been reported from Thailand (N = 39), 2,[10][11][12] Haiti (N = 1), 13 New Zealand (N = 1), 14 Australia (N = 1), 15 Israel (N = 2), 16,17 and Malaysia (N = 1), 18 and all cases, except for one patient returning from Israel, were indigenous cases. 17 In most cases, patients have a history of being recently exposed to wet environments (wastewater, rice paddies, swimming pool, tap water, or river) or farming occupations, which was shown in a series of 11 cases of Pythium keratitis in which 91% patients were farmers.…”

“…There are only four published reports of Pythium keratitis linking this infection to contact lens use, and all reported cases had a history of water contamination as well (river, tap water, and swimming pool). 12,[16][17][18] Unlike Pseudomonas aeruginosa or Acanthamoeba, filamentous fungi were historically infrequently linked to contact lens-associated keratitis. [19][20][21] In 2005, a multicountry outbreak of contact lens-associated keratitis caused by the Fusarium species occurred and was suspected to be linked with the use of a specific brand of contact lens multipurpose solution that was contaminated.…”

“…[10][11][12]14,[16][17][18]27 P. insidiosum poorly responds to conventional systemic or topical antifungal agents (i.e., amphotericin B and triazoles), because it lacks the drug target ergosterol in its cytoplasmic membrane. However, echinocandins, the antifungal agents that inhibit the β-glucan synthesis of the cell wall, may be effective in the treatment of pythiosis.…”

“…In the case of deep extension, the ocular structures must be removed by enucleation or evisceration to cure the disease. 2,17 For localized disease, a penetrating keratoplasty should be performed, because it seems to be the only conservative treatment. 11,13,15,16,18 Nevertheless, infection can post-operatively recur if organisms are left behind.…”