Objective: To reevaluate the necessity of empiric gram-negative therapy for postoperative endophthalmitis based on the recognition of aminoglycoside-induced toxic effects.
Methods: A review of 162 cases of culture-positive bacterial endophthalmitis to determine bacterial prevalence, antibiotic susceptibilities, and laboratory staining results of intraocular material.
Results: One hundred fifty (93%) gram-positive and 12 (7%) gram-negative isolates. All the gram-positive bacteria were susceptible to vancomycin hydrochloride; and gram-negative bacteria were susceptible to gentamicin sulfate, amikacin sulfate, and ceftazidime sodium. Bacterial rods were observed on smear of intraocular material in 10 gram-negative cases submitted for examination.
Conclusion: Vancomycin is an appropriate single agent if laboratory studies rule out gram-negative infection. In the absence of laboratory support, an aminoglycoside (possible toxic effects) or another gram-negative antibiotic (possibly ceftazidime) should also be administered.