New patterns of infecting organisms in late bleb-related endophthalmitis: a ten year review

To report the risk factors, causative organisms and visual outcomes in patients with late-onset bleb-related endophthalmitis.

Medical records of all patients with the clinical diagnosis of late-onset bleb-related endophthalmitis undergoing vitreous aspirates for culture at our institution from January 1987 to July 1996 were reviewed. Late-onset bleb-related endophthalmitis was defined as conjunctival injection, bleb purulence and intraocular inflammation developing at least 1 month following filtering surgery.

Forty-nine cases of bleb-related endophthalmitis developed in 42 patients (23 men, 19 women). Mean patient age was 62.1 +/- 19.3 years (range 5-94 years). Thirty-nine patients underwent prior filtering surgery (superior trabeculectomy, 24 eyes; inferior trabeculectomy, 10 eyes; combined superior trabeculectomy/cataract extraction, 4 eyes; posterior lip sclerectomy, 1 eye) and 3 had inadvertent blebs following cataract extraction. Endophthalmitis developed an average of 25.4 +/- 23.5 months (range 1-96 months) post-operatively. Antifibrosis agents were used in 25 of 39 eyes undergoing filtering surgery (mitomycin C, 13 eyes; 5-fluorouracil, 12 eyes). Bleb leaks were documented in a total of 32 of 49 (65%) cases either before or at the time of endophthalmitis diagnosis. Vitreous cultures were positive in 42 of 49 (86%) cases. The most frequently cultured organisms were Staphylococcus aureus (13), Staphylococcus epidermidis (12), Streptococcus species (8) and Haemophilus influenzae (2). A final visual acuity of 20/400 or better was achieved in 32 of 49 (65%) cases.

Staphylococcal species were the most frequently cultured organisms in this series and may be associated with better visual outcomes. Although a causal relationship cannot be established, these results suggest a strong association between bleb leaks and endophthalmitis.