VITREOUS CULTURES IN SUSPECTED ENDOPHTHALMITIS - BIOPSY OR VITRECTOMY

Background. Isolation of bacteria from vitreous biopsy often guides th erapy in suspected endophthalmitis. Therapeutic vitrectomy provides an additional source of culture material. The authors compared the abili ty of these two techniques to isolate organisms from patients with acu te endophthalmitis. Methods: In a large ophthalmic microbiology labora tory during a 4-year period, the authors analyzed 206 microbial cultur e results from patients with suspected endophthalmitis. Results: Two h undred six cases were evaluated. While cultures of vitreous biopsy spe cimens obtained using a needle and syringe were positive in 91 (53.8%) of 169 patients, culturing the contents of the vitrectomy cassettes p roduced positive cultures in 29 (74.8%) of 39 patients. Both technique s were performed on 23 patients. Vitreous biopsy allowed isolation of the causative organism in 43% of these patients, whereas vitrectomy wa s 76% successful. Both comparisons were significant at the P < 0.01 le vel. No positive vitreous biopsy cultures had associated negative vitr ectomy cultures. Conclusion: Culturing the contents of the vitrectomy cassette significantly increases the likelihood of obtaining a positiv e culture compared with merely culturing a vitreous biopsy.