Abstract
Abstract: :
Purpose: To compare the efficacy of a one–day versus three–day application of 0.5% topical levofloxacin in reducing ocular surface bacteria. Methods: This prospective randomized study assigned one hundred volunteers to receive one drop of topical 0.5% levofloxacin (4x/day) for one day (1–Day, n = 50) or three days (3–Day, n = 50) in one eye. Conjunctival cultures from both eyes were obtained in all subjects prior to (T0) and after the application of antibiotics (T1) with a moist cotton swab. The day after the completion of the antibiotic regimes, another culture was collected from all subjects after they received three additional drops of topical levofloxacin at five minute intervals (T2). They then received two drops of topical 5% povidone–iodine and another smear was collected (T3). All specimens were inoculated at 37°C for six days on solid and liquid culture media and aerobic/anaerobic bacterial growth was identified. Results: In the study eye, 82% of eyes in the 1–Day group and 74% in the 3–Day group had positive conjunctival cultures at baseline (P = 0.47). At T1, 46% of study eyes in the 1–Day group had positive cultures, compared to 34% in the 3–Day group (P = 0.3074). At T2, 30% of eyes in the 1–day group and 36% in the 3–day group had positive cultures (P = 0.671). Finally, at T3 there were 20% positive cultures in both groups (P = 1.000). Compared to their controls, cultures from both groups showed a significant reduction of bacteria at T1 (1–Day: P = 0.0038, 3–Day: P = 0.0025). On solid culture, most (>50%) of cultures were sterile for every group. The most commonly isolated bacteria were Coagulase Negative Staphylococcus, appearing in 69.4% of the 373 total isolated strains. Conclusions: The one–day application of topical 0.5% levofloxacin is as effective in eliminating bacteria from the conjunctiva as a three–day application. Both methods significantly remove microorganisms from the ocular surface.
Keywords: endophthalmitis • bacterial disease • antibiotics/antifungals/antiparasitics