Ocular Microbiology and Immunology Group
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2015 OMIG Abstract 11

Organ culture model for microbial keratitis in ex vivo rabbit and human corneas
Prashant Garg¹, Nagaveni S¹, Abigail Pinnock², Sanhita Roy¹, Stephen Rimmer², Ian Douglas²,
Sheila MacNeil^2
1LV Prasad Eye Institute, Hyderabad, India; ²The University of Sheffield, Sheffield, UK

Purpose: The aim of the present study was to develop a reproducible model of corneal infection using ex vivo organ culture of rabbit and human corneas.
Methods: Wild brown rabbit and cadaveric human corneas unsuitable for transplant were maintained in corneal organ culture for 24 or 48 hours at 37°C after being wounded with a scalpel, or injected intrastromally with 10⁸ CFU of Staphylococcus aureus, Pseudomonas aeruginosa or Candida albicans. Corneas were homogenized and subjected to microbial plate counting and the results are presented as colony-forming units (CFU). Corneas were histologically processed and sections were Gram-stained. Corneas not exposed to microbes were used as controls.
Results: Using the scalpel wounding method, CFU/cornea recovered after 24 hours were 5.1±1x10⁵ and 1.4±4.2x10⁶, (n=5), for S. Aureus, 1.9±2.9x10⁷ and 2.8±3.2x10⁷, (n=5) for P. aeruginosa and 3.0±6.0x10⁵ and 2.0±7.8x10⁶ (n=3) for C. albicans from rabbit and human corneas respectively. The injection method yielded a 10-fold increase (p<0.05) in detectable organisms compared with the scalpel method. There was no significant difference in CFU/cornea after 48h. Histology of the scalpel-wounded and injection models indicated extensive infiltration of P. aeruginosa throughout the entire cornea, with less infiltration observed for S. aureus and C. albicans.
Conclusions: Both scalpel wounding and injection methods were suitable for inducing infection in corneas maintained in organ culture. Differences between the CFU/cornea for rabbit and human corneas may be due to the expression of different antimicrobial peptides or surface receptors influencing colonization of the tissue. These simple and reproducible ex vivo models will be useful as an alternative to monolayer cells and in vivo models for investigating microbial keratitis.

Financial support: Wellcome trust, UK

C = Allergan India, NovaBay

2015 Agenda and Abstracts | < Previous | Next >