EXPERIENCE WITH A BROTH CULTURE TECHNIQUE FOR DIAGNOSIS OF BACTERIAL KERATITIS

Purpose: To determine if a broth culture technique is a practical mean s for bacteriological investigation of keratitis. Material and methods : Twenty-seven eyes of 27 patients with a clinical diagnosis of bacter ial keratitis were included in a prospective and non-comparative study at a Danish referral hospital. A corneal scrape was inoculated direct ly into broth medium which was transferred to the diagnostic laborator y for incubation and subculture. Results: Culture was negative in 4 pa tients, and 19 of the remaining 23 patients had a pure growth of eithe r Pseudomonas aeruginosa (n = 8), Staphylococcus aureus (n = 2), Strep tococcus pneumoniae (n = 2), Haemophilus influenzae biotype III (n = 1 ), Moraxella species (n = 1), Corynebacterium species (n = 1), or coag ulase-negative staphylococci (n = 4). In 4 patients there was a mixed Grampositive growth. There was no association between microbiological findings and previous topical antibiotic therapy Contamination and lac k of quantitative assessment of growth proved not to be a problem. Con clusions: By broth culture technique we identified a definite pathogen (P. aeruginosa, S. aureus or S. pneumoniae) in 44% of patients (95% b inomial confidence limits: 25-65%). The technique may replace the stan dard technique of direct plate culture under circumstances where it is difficult to keep a supply of fresh media or transport inoculated pla tes.