Microbiology and Immunology Group
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Purpose: To report clinical features, in vivo confocal microscopy (IVCM) characteristics and dual molecular diagnosis of microsporidial (Encephalitozoon hellem) keratoconjunctivitis acquired through avian transmission in an immunocompetent adult.
Dual Molecular Diagnosis of Microsporidia (Encephalitozoon hellem) Keratoconjunctivitis in an Immunocompetent Adult
Stephan Ong Tone1, Thuy Doan2, Deborah S. Jacobs1
1Massachusetts Eye and Ear, Harvard Medical School, Boston, MA; 2Francis I. Proctor Foundation, University of California, San Francisco, CA
Methods: A patient with unilateral keratoconjunctivitis underwent corneal IVCM (Rostock Cornea Module of the Heidelberg Retina Tomograph 3), metagenomic deep sequencing diagnosis (MDS) and polymerase chain reaction (PCR) confirmation of microsporidial (Encephalitozoon hellem) keratoconjunctivitis.
Results: A healthy 18-year-old female was referred with unilateral keratoconjunctivitis after cleaning a birdcage. There was failure to respond to a course of topical fluoroquinolones, steroid, and oral erythromycin after initial intolerance to oral doxycycline. Her best-spectacle corrected visual acuity was 20/40 in the left eye, which improved to 20/20 with pinhole. Her intraocular pressure was 23 mm Hg. She had 2+ papillae and follicles in the upper tarsal and lower palpebral conjunctiva. Her cornea showed multiple punctate epithelial opacities/inclusions in the lower two thirds with positive fluorescein staining but no epithelial defect. Her anterior chamber was clear with no keratic precipitates. Her right eye and dilated fundus exam in both eyes were unremarkable. IVCM demonstrated multiple round and ovoid bright double walled structures in the superficial epithelial debris, epithelium and at the level Bowmanís membrane and the sub-basal nerve plexus. No stromal abnormalities were detected. The patient was initially presumed to have Chlamydia Psittaci keratoconjunctivitis and was treated with topical 1% azithromycin (2 times daily) and reduction of steroid to 0.5% loteprednol once daily. PCR of conjunctival swab and serologic testing for Chlamydia Psittaci were negative. MDS of sample obtain at time of conjunctival swab for PCR was positive for Encephalitozoon hellem, a parasitic fungus in the phylum microsporidia, which was confirmed on subsequent PCR testing of initial specimen. Clinical improvement was observed but a subsequent 1-month course of topical 1% voriconazole (6 times daily) was administered with resolution of all signs and symptoms. Repeat IVCM demonstrated absence of the multiple round and ovoid structures previously seen.
Conclusion: IVCM may be used as a diagnostic tool to initiate therapy while corneal cultures or molecular testing are pending. MDS is emerging as a promising technology for pathogen detection in clinical samples. In this case, a dual molecular diagnosis, rather than diagnosis by conventional light microscopy, histology, electron microscopy, culture, cell culture, or serologic methods, was made in an immunocompetent patient with avian exposure after testing for Chlamydia Psittaci was negative. Clinical cure was attained with topical therapy.
Disclosure: N (SOT, TD); C (DJ, Novartis Pharma AG, Santen, Inc., SimpleContacts, TECLens)
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