Seasonal, Geographic, and Antimicrobial Resistance Patterns in Microbial Keratitis: 4-Year Experience in Eastern Pennsylvania. Issue 3 (March 2015)

• Record Type: Journal Article
• Authors: Ni, Nina; Nam, Enoch M.; Hammersmith, Kristin M.; Nagra, Parveen K.; Azari, Amir A.; Leiby, Benjamin E.; Dai, Yang; Cabrera, F. Abigail; Ma, Jenny F.; Lambert, Calvin E.; Honig, Stephanie E.; Rapuano, Christopher J.
• Is Part Of: Cornea. Volume 34:Issue 3(2015)
• Publication Date: 2015-03
• Subjects: microbial keratitis -- corneal ulcer -- seasonal variation -- geographic variation -- antimicrobial resistance; Cornea -- Periodicals; Cornea -- Periodicals; Cornée -- Périodiques; 617.719
• DOI: 10.1097/ICO.0000000000000352
• Languages: English
• ISSNs: 0277-3740

Abstract

Abstract : Purpose: The aim of this study was to review the demographics, causative organisms, seasonal and geographic variation, and antimicrobial resistance patterns of microbial keratitis at our institution over a 4-year period. Methods: Electronic medical records of all patients with microbial keratitis who underwent corneal culturing at a single institution in eastern Pennsylvania between January 1, 2009 and December 31, 2012 were reviewed. Results: A total of 311 patients representing 323 instances of infectious keratitis were analyzed. The most frequently implicated organisms in contact lens-related infections were Pseudomonas aeruginosa for bacteria and Fusarium species for fungus, compared with Staphylococcus aureus and Candida species in non–contact lens-associated bacterial infections. Bacterial keratitis occurred most frequently in spring and least frequently in winter ( P = 0.024). Patients who live in large fringe metro (suburban) areas accounted for the highest proportion of infectious keratitis cases. P. aeruginosa and methicillin-sensitive S. aureus isolates were highly susceptible to fluoroquinolones, whereas 32% of coagulase-negative staphylococcus isolates tested were resistant to moxifloxacin and gatifloxacin, and all methicillin-resistant S. aureus organisms tested were resistant to these 2 fluoroquinolones. No organisms tested were resistant to tobramycin, gentamicin, or vancomycin. No fungal infections tested were resistant to voriconazole. Conclusions: Most infectious keratitis occurred in nonwinter months and in patients from suburban counties. Although fluoroquinolones were effective against the most common bacteria, staphylococcal species exhibited a high rate of resistance, representing a therapeutic challenge given the increasing use of fluoroquinolones as first-line monotherapy. No organisms tested were resistant to tobramycin, gentamicin, vancomycin, or voriconazole.