Use of a low nutrient culture medium for the identification of bacteria causing severe ocular infection.

A low nutrient culture medium was used to identify the pathogens in four cases of persisting ocular infection. Bacto R2A agar was used in addition to conventional liquid- and solid-phase media to culture pathogenic bacteria from one case of recurrent keratitis, one case of suture-related keratitis with endophthalmitis and two eyes (two patients) with post-operative endophthalmitis. In each case, a pathogen was identified solely with R2A agar after culture for 6 days. Species isolated were Pseudomonas aeruginosa (one), Propionibacterium acnes (two) and Staphylococcus aureus (one). Antibiotic therapy was tailored to conform to the sensitivity of the cultured organism in each case. The use of Bacto R2A low nutrient agar should be considered in culture negative eyes not showing clinical improvement, or for chronic cases where bacteria may have become adapted to more stringent ocular environments.

Acanthamoeba sclerokeratitis: treatment with systemic immunosuppression.

OBJECTIVE: This study describes the clinical features, management, and outcome of 19 patients who had severe Acanthamoeba sclerokeratitis (ASK) unresponsive to conventional management, requiring systemic immunosuppression to control disease. DESIGN: Retrospective, non-comparative, interventional case series. PARTICIPANTS: Records of all patients with Acanthamoeba keratitis treated at Moorfields Eye Hospital between 1989 and 2000 were reviewed. From more than 200 patients, 19 who developed ASK treated with systemic immunosuppression were identified. MAIN OUTCOME MEASURES: Visual acuity, level of pain, and degree of inflammation were recorded after immunosuppressive treatment. RESULTS: ASK requiring immunosuppression occurred in 20 eyes of 19 patients (11 males and 8 females). The mean age (mean +/- standard deviation) at onset was 38.6 +/- 13.2 years. On presentation, best-corrected visual acuity was counting fingers or worse in 11 eyes (55%), 6/18 to 6/60 in 5 eyes (25%), and 6/12 or better in 4 eyes (20%). The mean time between onset of initial symptoms of Acanthamoeba keratitis and commencement of systemic immunosuppression was 4.8 +/- 3.5 months. The mean duration of immunosuppression required to control inflammation was 7.2 +/- 3.9 months. Severe scleritic pain remained uncontrolled in two patients and resulted in enucleation. Best-corrected visual acuity at final follow-up was counting fingers or worse in eight eyes (40%), 6/18 to 6/60 in six eyes (30%), and 20/40 or better in six eyes (30%). The mean follow-up period after resolution of inflammation was 24.3 +/- 20.9 months (range, 0.2-59.7 months). CONCLUSIONS: ASK is an uncommon complication of Acanthamoeba keratitis. The scleritis associated with this infection seems to be an immune-mediated response. After topical amebicidal treatment, systemic immunosuppression may be required to control the pain and tissue destruction associated with ASK.