The endophthalmitis vitrectomy study - Relationship between clinical presentation and microbiologic spectrum

Purpose: The authors determine if specific features of the clinical presentation of acute postoperative endophthalmitis correlate with the microbiologic culture results. Methods: A total of 420 patients who had clinical evidence of endophthalmitis within 6 weeks after cataract surgery or secondary intraocular lens implantation were evaluated as part of a randomized clinical trial. Results of cultures performed on aqueous and vitreous specimens obtained at presentation were categorized as follows: gram-positive coagulase-negative micrococci, ''other'' gram-positive, gram-negative, and equivocal/no growth. Results: Eleven features of the initial clinical presentation were associated with significant differences in the microbiologic spectrum (P < 0.05). Baseline factors correlating with higher rates of both gram-negative and other gram-positive isolates were: corneal infiltrate, cataract wound abnormalities, afferent pupillary defect, loss of red reflex, initial light perception-only vision, and symptom onset within 2 days of surgery. Gram-negative organisms did not grow in any eyes in which a retinal vessel could be visualized, and 61.9% of these eyes had equivocal or no growth. Diabetes mellitus was associated with a higher yield of gram-positive, coagulase-negative micrococci. Eye pain was not a discriminator for culture results. Conclusions: The presenting characteristics of acute endophthalmitis after cataract surgery may be helpful in predicting the most likely culture results. Such predictions do not appear sufficiently strong to guide the initial empiric choice of intravitreal antibiotics.