Eric W. Fitz, MD (New York, NY), Shaw Mahendra, BS (New York, NY), Richard B. Rosen, MD (New York, NY), Ronald C. Gentile, MD (New York, NY)

PURPOSE:

Endophthalmitis remains one of the most devastating complications of ophthalmic surgery. Timely treatment with appropriate antibiotics is necessary to prevent severe loss of vision. This study reviews microbial antibiotic resistance profiles of culture positive isolates in endophthalmitis.

METHODS:

All positive vitreous cultures in the microbiology records at the New York Eye and Ear Infirmary since the onset of sensitivity testing for fourth generation fluoroquinolones were reviewed (April 2004 to September 2005). Medical records were reviewed for clinical correlation. Endophthalmitis was classified as “post-operative” in eyes that had undergone intraocular surgery within 6 weeks, “bleb-related” in eyes with a filtering bleb, and “other” in eyes with trauma or a corneal abscess.

RESULTS:

42 positive vitreous cultures from 38 patients were identified. 76% of all isolates were gram positive (73% of the “bleb associated” 78% of the “post-op” and 75% of the “other”.) Overall, Staphylococcus and Streptococcus species were the most common pathogens. Gram negative pathogens included Pseudomonas, Serratia, and Moraxella species. All of the “bleb-related” and all of the “other” isolates were sensitive to a fourth generation fluoroquinolone. In contrast, all of the gramnegative “post-op” isolates, but only 64 to 65 percent of the gram-positive “post-op” isolates, were sensitive to a fourth generation
fluoroquinolone. See table 1 for a full listing of sensitivities to six common antibiotics.

CONCLUSION:

This study shows no resistance of bacterial isolates in culture positive endophthalmitis to empiric combination treatment with Vancomycin and Ceftazadime. However, overall sensitivity to a fourth generation fluoroquinolone was only 75%. Caution should be used when using fourth generation fluoroquinolones to treat endophthalmitis, especially as monotherapy in post-operative patients.
TABLE 1: Sensitivity of bacterial isolates in endophthalmitis.