Padmanabhan Saraswathi1, Roger W Beuerman2. 1. Singapore Eye Research Institute (SERI), Singapore. 2. Singapore Eye Research Institute (SERI), Singapore; Duke-NUS SRP Neuroscience and Behavioural Disorders and Emerging Infectious Diseases, Singapore; Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore. Electronic address: rwbeuerman@gmail.com.
Abstract
PURPOSE: Microbial biofilms commonly comprise part of the infectious scenario, complicating the therapeutic approach. The purpose of this study was to determine in a mouse model of corneal infection if mature biofilms formed and to visualize the stages of biofilm formation. METHODS: A bacterial keratitis model was established using Pseudomonas aeruginosa ATCC 9027 (1 × 10(8) CFU/ml) to infect the cornea of C57BL/6 black mouse. Eyes were examined post-infection (PI) on days 1, 2, 3, 5, and 7, and imaged by slit lamp microscopy, and light, confocal, and electron microscopy to identify the stages of biofilm formation and the time of appearance. RESULTS: On PI day 1, Gram staining showed rod-shaped bacteria adherent on the corneal surface. On PI days 2 and 3, bacteria were seen within webs of extracellular polymeric substance (EPS) and glycocalyx secretion, imaged by confocal microscopy. Scanning electron microscopy demonstrated microcolonies of active infectious cells bound with thick fibrous material. Transmission electron microscopy substantiated the formation of classical biofilm architecture with P. aeruginosa densely packed within the extracellular polymeric substances on PI days 5 and 7. CONCLUSION: Direct visual evidence showed that biofilms routinely developed on the biotic surface of the mouse cornea. The mouse model can be used to develop new approaches to deal therapeutically with biofilms in corneal infections.
PURPOSE: Microbial biofilms commonly comprise part of the infectious scenario, complicating the therapeutic approach. The purpose of this study was to determine in a mouse model of corneal infection if mature biofilms formed and to visualize the stages of biofilm formation. METHODS: A bacterial keratitis model was established using Pseudomonas aeruginosa ATCC 9027 (1 × 10(8) CFU/ml) to infect the cornea of C57BL/6 black mouse. Eyes were examined post-infection (PI) on days 1, 2, 3, 5, and 7, and imaged by slit lamp microscopy, and light, confocal, and electron microscopy to identify the stages of biofilm formation and the time of appearance. RESULTS: On PI day 1, Gram staining showed rod-shaped bacteria adherent on the corneal surface. On PI days 2 and 3, bacteria were seen within webs of extracellular polymeric substance (EPS) and glycocalyx secretion, imaged by confocal microscopy. Scanning electron microscopy demonstrated microcolonies of active infectious cells bound with thick fibrous material. Transmission electron microscopy substantiated the formation of classical biofilm architecture with P. aeruginosa densely packed within the extracellular polymeric substances on PI days 5 and 7. CONCLUSION: Direct visual evidence showed that biofilms routinely developed on the biotic surface of the mouse cornea. The mouse model can be used to develop new approaches to deal therapeutically with biofilms in corneal infections.
Authors: Michaelle Chojnacki; Alesa Philbrick; Benjamin Wucher; Jordan N Reed; Andrew Tomaras; Paul M Dunman; Rachel A F Wozniak Journal: Antimicrob Agents Chemother Date: 2018-12-21 Impact factor: 5.191
Authors: L Edward Clemens; Jesse Jaynes; Edward Lim; Satya S Kolar; Rose Y Reins; Hasna Baidouri; Samuel Hanlon; Alison M McDermott; Kathryn W Woodburn Journal: Invest Ophthalmol Vis Sci Date: 2017-12-01 Impact factor: 4.799