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Diana Gabriela Ponce-Angulo, Luis Antonio Bautista-Hernández, Rosa Paulina Calvillo-Medina, Gerardo Aparicio-Ozores, Rosa María Ribas-Jaimes, Victor Manuel Bautista; Microscopic characterization of mouse model mixed keratitis. Invest. Ophthalmol. Vis. Sci. 2018;59(9):506.
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© ARVO (1962-2015); The Authors (2016-present)
Corneal infections have been described originated by bacteria, fungi, virus, and co-infection, which can involve more than two infectious agents. In the world, more than two millions two cases have been reported. There are few reports of polimicrobial infections in ophthalmology, however, cases are increasing every year. Several inveestigations have been developed an effective animal model in order to study and understand co-infectious keratitis physiology. Based on these information the aim of this study was performed a mixed keratitis murine model of Staphylococcus aureus and Fusarium falciforme and microscopic characterization.
We performed an immunosuppressants ascending concentration curve (methylprednisolone-cyclophosphamide), using ocular clinical strains and BALB / c female mice at 6-8 weeks old. We performed an ocular injury by the pocket technique. The rigth eyes were inoculated with Fusarium falciforme (1x105 conidia) and S. aureus (1X105 UFC). The mice were sacrificed at 72 h after induction of infection, the right eyes were enucleated and preserved with formaldehyde. Histological preparations were developed and stained with H-E and PAS stains. In another hand, stained preparations with calcofluor white and propidium iodide were made and analyzed by fluorescence microccopy and finally transmission microscopy was performed to observed the microorganisms prescence and morphology.
It is important to mention that this is the first experimental work where used a combination of two immunosuppressants cyclophosphamide-methylprednisolone obtaining saticfactory results with cyclophosphamide 150 mg/kg and methylprednisolones 80 mg/kg of mouse weight. We found that the microbial distribution was in the cornea at stroma level and epithelium. In some cases the F. falciforme hyphae were located at lens level, the previous observations were revealed by histopathological and fluorescence analysis and finally the transmission electron microscopy suggested biofilm formation by S. aureus and F. falciforme in mono and mixed infection.
The microbial distribution was determinated by fluorescence and histopalogic analysis observing that the S. aureus had a dsitribution at epithelial level while F. falciforme was found at stromal, retina and lens level. We found that both microorganisms infected the mice cornea and induced a mixed keratitis and biofilm formation.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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