To investigate the spectrum of organisms causing culture-proven endophthalmitis and their susceptibilities to commonly used antimicrobial agents over 10 years.

Retrospective, noncomparative, consecutive case series.

Medical records were reviewed of all cases with culture-proven endophthalmitis at a single institution from 2002 through 2011. The outcome measures included all intravitreal isolates identified as well as antibiotic susceptibilities.

A total of 448 organisms were isolated during the study interval. The most common organisms identified were Staphylococcus epidermidis in 30.1% (135/448), Streptococcus viridians group in 10.9% (49/448), Staphylococcus aureus in 7.8% (35/448), Candida albicans in 5.8% (26/443), other coagulase-negative staphylococci in 6.0% (27/448), Propionibacterium acnes in 4.7% (21/448), and Pseudomonas aeruginosa in 3.1% (14/448). Overall, 327 (72.9%) of 448 isolates were gram-positive organisms, 48 (10.7%) of 448 isolates were gram-negative organisms, 71 (15.8%) of 448 isolates were fungi, and 2 (0.4%) of 448 isolates were viruses. For gram-positive organisms, susceptibilities were the following: vancomycin, 100%; gentamicin, 88.0%; sulfamethoxazole/trimethoprim, 77.5%; levofloxacin, 58.5%; oxacillin, 54.7%; ciprofloxacin, 51.0%; gatifloxacin, 51.0%; and moxifloxacin, 47.0%. For gram-negative organisms, susceptibilities were the following: ceftazidime, 100%; levofloxacin, 100%; ciprofloxacin, 95.0%; tobramycin, 90.6%; gentamicin, 80.6%; and sulfamethoxazole/trimethoprim, 59.4%.

In the current study, no single antibiotic provided coverage for all of the microbes isolated from eyes with endophthalmitis. Combination therapy generally is the recommendation as the initial empiric treatment of suspected bacterial endophthalmitis. Appropriate history and characteristic clinical features may guide the use of initial antifungal agents.