Lagenidium sp. ocular infection mimicking ocular pythiosis

Abstract

This is a report of a Lagenidium sp. in a Thai patient who was diagnosed with severe keratitis that was unresponsive to antibacterial and antifungal drugs. Examination of a corneal biopsy specimen confirmed the presence of aseptate hyphae. The internal transcribed spacer DNA sequence of the strain isolated showed 97% identity with Lagenidium giganteum and other Lagenidium species.

Fig 1

(A) Corneal infiltration with a reticular pattern and a feathery edge. (B) In vivo confocal microscopy showing numerous fungal elements as branching with interlocking and hyperrefractive thin lines in the corneal stroma. (C) Broad, rare, septate hyphae in a KOH preparation. Magnification, ×40. (D) Longitudinal and transverse broad hyphae. GMS staining; magnification, ×40.

Fig 2

(A) A 48-h culture on 2% Sabouraud dextrose agar of the Lagenidium sp. recovered from the patient whose case is reported here. In this medium, the strain developed submerged glabrous white/yellowish colonies in less than 24 h. (B) Presence of broad rarely septate hyaline hyphae. Note that the strain does not develop fruiting bodies in this medium. Bar, 18 μm. (C) Development of several sporangia with zoospores in liquid induction medium (arrows). Several swimming zoospores can be observed around the sporangia. Although the diameter of the Lagenidium hyphae from this case is greater, the hyphae have several phenotypic characteristics in common with P. insidiosum. Bar, 45 μm.