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Yingyu Li, Pei Zhang, Ziyuan Liu, Wei Wang; Comparison Study on Aspergillus Pathogenicity of Corneal Clinical Isolates And Standard Strain: The Relationship Between Invasiveness And Growth Characteristics. Invest. Ophthalmol. Vis. Sci. 2019;60(9):869. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
This study combined the clinical and pathological features with growth characteristics of Aspergillus isolating from cornea in vitro to explore the pathogenic mechanism of Aspergillus keratitis.
A retrospective study of patients with Aspergillus keratitis was conducted. The clinical information of 8 cases was collected and analyzed, pathological section observed microscopically. Compared with the standard strain, 2 Aspergillus corneal clinical isolates were inoculated in different nutrient media, including PDA media, YG media and SGA media. On the solid media we observed the colony morphology, while in the liquid media the optical density (OD) was recorded to generate growth curves for each fungus and medium.
Most cases of Aspergillus keratitis could get rapidly progression with insidious onset. Pathologically, Aspergillus was widely distributed in differential depths of corneal tissue with various growth forms and inflammatory cells infiltrating, but inflammatory cells couldn’t limit the pathogen spread. Aspergillus could break the Descemet’s membrane without corneal perforation. In vitro, on solid media, the diameter and density of clinical colonies was greater than standard one, so was the diameter of conidiation zone. New colonies could be observed in the clinical plates. In liquid media, the differences between clinical isolates and standard strains would be more obvious in the simple composition medium (PL=0.006，PW=0.036). The clinical isolates had an advantage of ODs and growth speed over the standard one.
Compared with standard strain, the corneal clinical isolates of Aspergillus had stronger ability of growth, reproduction, dispersion and higher adaptive capacity to poorer nutrition condition.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
Fig1 a, b, c (PAS, 200×) Aspergillus and inflammatory cells were widely distributed in all depths of corneal tissue. Epithelial layer and Bowman’s layer were destroyed, and stroma was swollen. d (PAS, 400×) Descemet’s membrane broke. e (PAS, 1000×) Split of Descemet’s membrane. f (PAS, 1000×) The Aspergillus grew in the Descemet’s layer. g, h, i (PAS, 1000×) Aspergillus presented various growth forms and couldn’t be controlled by inflammatory cells.
The colonies of different strains on different media, incubating at 29°C for 96h. New colonies could be seen in the clinical plates.
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