In vivo confocal microscopy appearance of Fusarium and Aspergillus species in fungal keratitis

• Published in: British journal of ophthalmology Vol. 101; no. 8; p. 1119
• Main Authors: Chidambaram, Jaya Devi, Prajna, Namperumalsamy Venkatesh, Larke, Natasha, Macleod, David, Srikanthi, Palepu, Lanjewar, Shruti, Shah, Manisha, Lalitha, Prajna, Elakkiya, Shanmugam, Burton, Matthew J
• Format: Journal Article
• Language: English
• Published: England 01-08-2017
• Subjects: Adult; Aged; Aspergillosis - diagnostic imaging; Aspergillus - isolation & purification; Corneal Ulcer - diagnostic imaging; Corneal Ulcer - microbiology; Eye Infections, Fungal - diagnostic imaging; Female; Fusarium - isolation & purification; Humans; Keratitis - diagnostic imaging; Keratitis - microbiology; Male; Microscopy, Confocal; Middle Aged; Young Adult; Infection; Cornea; Microbiology; Imaging; Diagnostic tests/Investigation
• ISSN: 1468-2079
• DOI: 10.1136/bjophthalmol-2016-309656

Clinical outcomes in fungal keratitis vary between
and
spp, therefore distinguishing between species using morphological features such as filament branching angles, sporulation along filaments (adventitious sporulation) or dichotomous branching may be useful. In this study, we assessed these three features within Heidelberg Retina Tomograph 3 in vivo confocal microscopy (IVCM) images from culture-positive
and
spp keratitis participants.
Prospective observational cohort study in Aravind Eye Hospital (February 2011-February 2012). Eligibility criteria: age ≥18 years, stromal infiltrate ≥3 mm diameter,
or
spp culture-positive.
previous/current herpetic keratitis, visual acuity <6/60 in fellow eye, >80% corneal thinning. IVCM was performed and images analysed for branch angle, presence/absence of adventitious sporulation or dichotomous branching by a grader masked to the microbiological diagnosis.
98 participants were included (106 eligible, 8 excluded as no measurable branch angles); 68 were positive for
spp, 30 for
spp. Mean branch angle for
spp was 59.7° (95% CI 57.7° to 61.8°), and for
spp was 63.3° (95% CI 60.8° to 65.8°), p=0.07. No adventitious sporulation was detected in
spp ulcers. Dichotomous branching was detected in 11 ulcers (7
spp, 4
spp).
There was very little difference in the branching angle of
and
spp. Adventitious sporulation was not detected and dichotomous branching was infrequently seen. Although IVCM remains a valuable tool to detect fungal filaments in fungal keratitis, it cannot be used to distinguish
from
spp and culture remains essential to determine fungal species.