Purpose
To investigate the spectrum of organisms causing culture-proven endophthalmitis and their susceptibilities to commonly used antimicrobial agents over 10 years.
Design
Retrospective, noncomparative, consecutive case series.
Methods
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.
Results
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%.
Conclusions
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.
Infectious endophthalmitis is a severe intraocular inflammation resulting from many different causes, including intraocular surgery, trauma, or systemic infection. The manifestations typically lead to severe vision loss and ocular morbidity. The treatment of endophthalmitis involves identification of the etiologic organisms through culture of intraocular fluids and prompt initiation of broad-spectrum antimicrobial therapy as indicated. As soon as culture results are available, therapy is tailored further to the causative organisms.
Strategies for both prevention and treatment of endophthalmitis include evaluation of emerging bacterial strains resistant to frequently used antibiotics and evaluation of the microbial spectrum of newer antimicrobial medications. The purpose of the current study was to investigate the spectrum of organisms causing culture-proven endophthalmitis and their susceptibilities to commonly used antimicrobial agents at a university referral center between 2002 and 2011.
Methods
The current study was approved by the Institutional Review Board of the University of Miami School of Medicine Medical Sciences Subcommittee for the Protection of Human Subjects. This was a retrospective, noncomparative, consecutive case series. The microbiology records were reviewed of all cases with culture-proven endophthalmitis (positive culture results from the vitreous cavity) at the Bascom Palmer Eye Institute between January 1, 2002, and December 31, 2011. Further comparison was made between these data and similar data from the same institution obtained between January 1, 1996, and December 31, 2001. The outcome measures included intravitreal isolates identified as well as antibiotic susceptibilities. Susceptibility testing of the intraocular isolates was performed using an automated system, the VITEK (Automatic Microbial System; Biomerieux Vitek, Hazelwood, Missouri, USA) or the E test (A. B. Biodisk, NA; Remel, Lenexa, Kansas, USA).
Results
In the 10-year timeframe of the current study, 448 organisms were identified in patients with culture-proven endophthalmitis from the microbiology records of a university referral center. Overall, 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% (26/448), other coagulase-negative staphylococci in 6.0% (27/448), Propionibacterium acnes in 4.7% (21/448), and Pseudomonas aeruginosa in 3.1% (14/448). Study isolates included gram-positive organisms in 327 (72.9%) of 448 organisms, gram-negative isolates in 48 (10.7%) of 448 organisms, fungi in 71 (15.8%) of 448 organisms, and viruses in 2 (0.4%) of 448 organisms ( Table 1 ).
| Vitreous Isolates | Current Study at BPEI 2002 through 2011 | Prior Study at BPEI 1996 through 2001 a | ||
|---|---|---|---|---|
| % of Total | No. (n = 448) | % of Total | No. (n = 313) | |
| Staphylococcus epidermidis | 30.1 | 135 | 27.8 | 87 |
| Streptococcus viridans group b | 10.9 | 49 | 12.8 | 40 |
| Staphylococcus aureus | 7.8 | 35 | 7.7 | 24 |
| Candida albicans | 6.3 | 28 | 2.9 | 9 |
| Coagulase-negative Staphylococcus (other) c | 6.0 | 27 | 9.3 | 29 |
| Propionibacterium acnes | 4.7 | 21 | 7.0 | 22 |
| Pseudomonas aeruginosa | 3.1 | 14 | 2.2 | 7 |
b Streptococcus viridans group: S. salivarius , S. salivarius , S. miti , S. acidominimus , S. constellatus , S. anginous , S. intermidius .
c Coagulase-negative Staphylococcus (other): S. haemolyticus, S. simulans , S. cohnii , S. warnerii , S. xylosus , S. sciuri , S. auricularis , and S. hominis .
The gram-positive and gram-negative antibiotic susceptibilities of the most commonly identified endophthalmitis-causing organisms are shown in Tables 2 and 3 , respectively. Among the 327 gram-positive organisms identified, the 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%. Among the 48 gram-negative organisms, the susceptibilities were the following: ceftazidime, 100%; levofloxacin, 100%; ciprofloxacin, 95.0%; tobramycin, 90.6%; gentamicin, 80.6%; and sulfamethoxazole/trimethoprim, 59.4%.
| Vitreous Isolates | Current Study at BPEI 2002 through 2011 (n = 327), % of Total | Previous Study at BPEI 1996 through 2001 a (n = 246), % of Total |
|---|---|---|
| Vancomycin | 100.0 | 100.0 |
| Gentamicin | 88.0 | 78.4 |
| Sulfamethoxazole/trimethoprim | 77.5 | NC b |
| Levofloxacin | 58.5 | NC b |
| Oxacillin | 54.7 | NC b |
| Ciprofloxacin | 51.0 | 68.3 |
| Gatifloxacin | 51.0 | NC b |
| Moxifloxacin | 47.0 | NC b |
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