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Aaron J Smith, Taylor Smith, Suzanne Hoadley, Kimberly Williams Crowder; Comparing Culturing Techniques in Corneal Ulcers. Invest. Ophthalmol. Vis. Sci. 2014;55(13):2845.
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© ARVO (1962-2015); The Authors (2016-present)
To compare two different culturing techniques in patients with corneal ulcers treated by ophthalmologists at the University of Mississippi Medical Center.
Patients presenting with corneal ulcers that the treating ophthalmologist determines warrants cultures were randomly assigned into one of two groups. One group of cultures were collected using dry sterile cotton tip applicators and the other group of cultures were collected using sterile cotton tip applicators moistened with thioglycollate broth. ulcers were randomized to the two different groups. The culturing technique and culturing mediums were the same for each group. Culture results were analyzed to see if there is a statistically significant difference between the two groups in regards to positive culture yield. Secondary information was observed will be characteristics of the ulcers (size, location, associated hypopyon) as well as species of organisms isolated. Based on the gathered information, we aim to allow treating ophthalmologists to use techniques what will increase positive culture results allowing more targeted antibiotic selection toward the isolated organism.
Currently 14 total eyes have been cultured with presenting visual acuity ranging from 20/25 to NLP. 9 of 14 had visual acuity of 20/70 or worse. 50% of ulcers were considered centrally located. A total of 7 dry swabs and 7 moistened swabs were performed. Dry swabs revealed only 1 of 7 positive culture results(14.3%) while 6 of 7 moistened swabs revealed positive culture results (85.7%). This proved to be a statistically significant difference between culturing techniques (p=0.008). Study is ongoing and data continues to be collected.
Based on relatively small sample size, performing cultures with a cotton swab moistened with Thioglycollate broth is superior to performing cultures with a dry cotton swab alone. 50% of ulcers had positive cultures. Sterile cotton swabs appear to be an effective culturing instrument. The presence of a hypopyon was associated with an increased likelihood of a positive culture, but this was not statistically significant. Contact lens usage and trauma were the most common risk factors observed.
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