Nocardia farcinica keratitis in a contact lens wearer
Photographer: Stefani Karakas
Contributor: Brittni A. Scruggs, MD, PhD
September 18, 2017
A 43-year-old woman with poor contact lens hygiene presented with two weeks of redness, pain, photophobia, and decreased vision of the right eye (OD). Visual acuity was 20/60 OD, and her anterior segment examination is documented in Figures 1-3. She was started on two fortified topical antibiotics, topical amphotericin, oral valacyclovir, and a topical cycloplegic, and corneal cultures were collected. Confocal microscopy showed numerous activated keratocytes without definitive hyphae or amoebic cysts (Fig 4). Corneal cultures were positive for >100 colonies of Nocardia farcinica. Topical amikacin 10 mg/mL and oral trimethoprim-sulfamethoxazole were added to her regimen. Within two weeks, her symptoms resolved and vision improved to 20/15 OD. Her drops were slowly tapered over three months.
Nocardia keratitis (NK) is a rare cause of bacterial keratitis that mimics fungal infections and, as a result, is often diagnostically challenging. Nocardia are gram-positive, aerobic bacteria of the actinomycetes order that are found in microflora of soil, dust, decaying vegetation, etc (1). NK classically leads to a wreath-like arrangement of patchy, anterior stromal infiltrates in the setting of trauma, contact lens use, or LASIK (1, 2). The course of NK is usually slowly progressive; however, these infections are commonly recalcitrant unless Nocardia-specific treatment (e.g., amikacin and sulphonamides) is initiated early (1, 2). Topical corticosteroids should be avoided prior to adequate treatment of Nocardia (1).
- Sridha, M.S., Gopinathan, U., Garg, P., Sharma, S., Rao, G.N. "Ocular nocardia infections with special emphasis on the cornea." Surv Ophthalmol. 45 (5): 361-78 (2001).
- Garg, P. "Fungal, Mycobacterial, and Nocardia infections and the eye: an update." Eye, 26 (2): 245–251 (2012).
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