CLINICOPATHOLOGIC AND ULTRASTRUCTURAL STUDY OF ENDOGENOUS KLEBSIELLA PNEUMONIAE ENDOPHTHALMITIS

Systematic review of 342 cases of endogenous bacterial endophthalmitis

We review a total of 342 cases of endogenous bacterial endophthalmitis reported between 1986 and 2012. Predisposing conditions were present in 60%, most commonly diabetes, intravenous drug use, and malignancy. The most common sources of infection were liver, lung, endocardium, urinary tract, and meninges. Systemic features such as fever were present in 74%, hypopyon in 35%, and an absent fundal view in 40%. Diagnostic delay occurred in 26%. Blood cultures were positive in 56%, and at least one intraocular sample was positive in 58% (comprising 26% anterior chamber samples, 59% vitreous taps, and 41% vitrectomy specimens). Worldwide, Gram negative infections (55%) were more frequent than Gram positive (45%) infections, particularly in Asia. Over the last decade, 11% of eyes were treated with systemic antibiotics alone, 10% intravitreal antibiotics alone, 36% systemic plus intravitreal antibiotics, and 20% systemic plus intravitreal antibiotics plus pars plana vitrectomy. The most commonly used intravitreal antibiotics were vancomycin (for Gram positive infection) and ceftazidime (Gram negative). The median final visual acuity was 20/100, with 44% worse than 20/200. Among all cases, 24% required evisceration or enucleation, and mortality was 4%. Both intravitreal dexamethasone and vitrectomy were each associated with a significantly greater chance of retaining 20/200 or better and significantly fewer eviscerations or enucleations-these warrant further study. For most patients, treatment should include a thorough systemic evaluation and prompt intravitreal and systemic antibiotics.

The diabetic ocular environment facilitates the development of endogenous bacterial endophthalmitis

PURPOSE

We tested the hypothesis that changes in the diabetic ocular environment facilitate the development of endogenous bacterial endophthalmitis (EBE).

METHODS

C57BL/6J mice were rendered diabetic with streptozotocin (STZ) for 1, 3, or 5 months' duration. Diabetic and age-matched nondiabetic mice were tail vein-injected with 10(8) CFU of Klebsiella pneumoniae, a common cause of EBE in diabetics. After either 2 or 4 days postinfection, the EBE incidence was assessed by electroretinography, histology, bacterial counts, and myeloperoxidase ELISAs. Blood-retinal barrier (BRB) permeability in uninfected diabetic mice also was determined.

RESULTS

No cases of EBE were observed among the 1-month diabetic group. Extending the time from diabetes induction to 3 months resulted in a 23.8% EBE incidence after 2 days, and a 22% incidence after 4 days. The incidence of EBE increased to 27% in the 5-month diabetic group. Infected eyes had an average 8.01 × 10(2) and 6.19 × 10(4) CFU/eye for the 3- and 5-month diabetic groups, respectively. There was no significant difference in BRB permeability between control and 1-month uninfected diabetic mice. However, 3- and 5-month diabetic mice had significantly greater BRB permeability than control mice. These results suggested that increasing the time from STZ diabetes induction to 3 and 5 months resulted in an ocular environment more conducive to the development of EBE.

CONCLUSIONS

These results demonstrated a correlation between an increase in BRB permeability and an increase in EBE incidence, supporting the hypothesis that diabetic ocular changes contribute to the development of EBE.