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Thomas Chris McCurry, Chang Lee, Jeffrey Golen; Bacterial Keratitis in Central Virginia. Invest. Ophthalmol. Vis. Sci. 2016;57(12):326.
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© ARVO (1962-2015); The Authors (2016-present)
The purpose of this study was to review the spectrum of disease and antibiotic susceptibilities of bacterial keratitis at a major tertiary care referral eye center in central Virginia.
Medical records of all patients with microbial keratitis from January 1, 2010, to September 30, 2015, at the University of Virginia Health System were reviewed.
A total of 282 cases of presumed bacterial keratitis were analyzed. 164 (58%) cases were cultured. Of the 164 cases cultured, 81 (49%) showed positive results. Seventy-three (90%) were positive for bacteria and 8 (10%) were positive for fungus. Gram-positive bacteria were found in 62% of bacterial-proven cultures. Of the gram-positive bacteria, coagulase-negative Staphylococcus was most common at 33%; Streptococcus pneumonia and Staphylococcus aureus were the next most common at 16% and 12%, respectively. Pseudomonas aeruginosa was the most common gram-negative bacteria isolated at 57% of all gram-negative isolates. Contact lens wear was found in 53% of the bacterial keratitis cases. The most common organism in contact lens-associated bacterial keratitis was P. aeruginosa (48%). In non-contact lens-related ulcers, the most common organism was coagulase-negative Staphylococcus (25%). P. aeruginosa showed no resistance to ciprofloxacin, levofloxacin and moxifloxacin. Moxifloxacin was not tested against any other gram negative bacteria. There were no cases of resistance of gram-positive bacteria to moxifloxacin, although there were no cases of S. aureus tested against moxifloxacin. 43% of S. aureus was resistant to Oxacillin, and 60% of S. aureus was resistant to levofloxacin. No organisms tested were resistant to gentamicin, tobramycin or vancomycin.
Gram positive bacteria are the most common cause of bacterial keratitis at our institution. However, among contact-lens wearers, P. aeruginosa is the most common organism. There was no resistance of P. aeruginosa to fluoroquinolones. S. aureus was found to have a high rate of resistance to oxacillin. Although no cases of S. aureus were tested against moxifloxacin it was found to have a high rate of resistance to a third-generation fluoroquinolone, levofloxacin. This could signify a therapeutic challenge since fluoroquinolones are increasingly used as first-line monotherapy. No organisms tested were resistant to gentamicin, tobramycin or vancomycin. Fungal ulcers constituted 10% of our culture-positive keratitis.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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