In-use study of potential bacterial contamination of ophthalmic moxifloxacin

PURPOSE: To determine the contamination rate of topical moxifloxacin 0.5% (Vigamox) after clinical use for preoperative and postoperative prophylaxis for cataract surgery. SETTING: Bascom Palmer Eye Institute, Miami, Florida, USA. METHODS: A total of 61 bottles of moxifloxacin were collected in a 2-month time period after use preoperatively by patients (n = 21, mean 2.2 days), postoperatively by patients (n = 16, mean 7.2 days), or by nurses in the operating room (n = 24). For each bottle, cultures of the cap, tip, external thread, and solution were inoculated onto chocolate agar plates and incubated at 35 degrees for 7 days. A total of 13 bottles of benzalkonium chloride (BAC)-preserved gatifloxacin ophthalmic solution (Zymar) were also cultured in a similar manner for comparison. RESULTS: No organisms were found by cultures of the cap, tip, or solution from any bottle in the study. One colony of coagulase-negative Staphylococcus was recovered from the thread of 1 Vigamox bottle. This bottle had negative cultures from its cap, tip, and solution. CONCLUSIONS: The only contaminant found in this study was cultured from the bottle thread. This is a location with a high rate of skin contact and minimal solution contact. The remaining cultures from this bottle were negative, showing the solution's ability to self-preserve. These data demonstrate that BAC-free Vigamox can be treated no differently than BAC-preserved solutions by patients and medical staff, without concern for solution contamination.