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.