Purpose: To examine the clinical and microbiological profile of Bacillus keratitis.
Methods: A retrospective review was done of all medical and laboratory records of patients with infectious keratitis in an urban tertiary level eye-care center in South India between January 1991 and June 1997.
Results: Nineteen eyes of 17 patients having microbiologically proven Bacillus keratitis were reviewed. The mean age of the patients was 32.64 years (range, 3-70). The duration of symptoms ranged from 1 day to 3 months, with 11 eyes seen within a week of onset of symptoms. Trauma (five eyes), lagophthalmos (two eyes), topical corticosteroid therapy (one eye), bullous keratopathy (two eyes), previous corneal scars (two eyes), and diabetes (one eye) were identified as predisposing factors. Severe corneal features, disproportionate to the duration of symptoms, were present in most of the eyes. Gram stain of corneal scrapings showed variably stained bacilli in eight (42.1%) cases. Polymicrobial infection was present in six eyes (two fungal, four bacterial). Of the 16 isolates tested for in vitro antibiotic susceptibility, 100% were sensitive to gentamicin, 15 (93.75%) were sensitive to ciprofloxacin and norfloxacin, 14 (87.5%) were sensitive to chloramphenicol, and 10 (62.5%) were sensitive to cefazolin. Whereas 12 (63.1%) eyes required only medical therapy, adjunctive procedures were required in seven (36.8%) eyes. The ulcers healed (mean time to healing, 37.4+/-28.6 days) in 16 eyes (lost to follow-up, three). Visual acuity had improved after treatment in 10 (71.4%) of 14 eyes in whom vision could be recorded.
Conclusion: Bacillus is an unusual pathogen in the clinical setting of infectious keratitis. The infection is mostly amenable to treatment with commonly used antibiotics, and the final outcome is often satisfactory.