Long-term effects of cataract surgery with topical levofloxacin on ocular bacterial flora

Abstract

To clarify the long-term effect of topical antibiotics on the ocular bacterial flora after cataract surgery. Miyata Eye Hospital, Miyazaki, Japan. Prospective case series. Patients who had cataract surgery between November 2014 and January 2015 were included. Levofloxacin 1.5% was administered 4 times a day by topical instillation from 3days before surgery to 1month postoperatively. The conjunctival sacs of patientswere scraped before the procedure and 0, 3, 6, 9, and 12months after the last instillation. The samples were cultured, and minimum inhibitory concentrations (MICs) of levofloxacin for Staphylococcus epidermidis and Propionibacterium acnes were evaluated using mixed-effects models. The study evaluated 50 patients. Diverse bacterial species, predominantly S epidermidis and P acnes, were isolated before the application of topical levofloxacin. Bacterial diversity was substantially reduced after the final topical levofloxacin application and subsequently increased after 3months. However, the geometric mean levofloxacin MICs for S epidermidis isolates were still significantly higher at 0months and 3months than before treatment (P<.01 and P=.03, respectively) and reached pretreatment levels 6months and 12months after the last application. Propionibacterium acnes did not show significant changes in the geometric mean levofloxacin MIC over time. The restoration of the bacterial flora required more than 6months after cataract surgery and topical levofloxacin.