A prospective study determining the efficacy of topical 0.5% levofloxacin on bacterial flora of patients with chronic blepharoconjunctivitis

Abstract

To determine the efficacy of conjunctival bacterial eradication following a 1-day, 3-day and 7-day application of topical 0.5% levofloxacin, with and without eyelid scrub, in patients with chronic blepharoconjunctivitis (CBC). Patients with CBC (n = 60) were prospectively randomized to three groups (n = 20 in each group): no antibiotic treatment, topical levofloxacin four times per day in both eyes, and eyelid scrub in addition to topical levovofloxacin four times a day in both eyes. Patients without CBC (n = 40) were enrolled as the negative control group. Cultures of the conjunctiva were obtained from both eyes at baseline, 1 day, 3 days, and 7 days following treatment. The most common bacteria isolated for all groups at baseline were coagulase-negative Staphylococcus. Eight patients did not complete the study. The remaining 52 patients with CBC had a significantly higher rate of positive thioglycolate broth cultures (94%) compared to a 58% positive culture rate in patient without CBC (P < 0.0001). Treatment with at least 3 days of topical antibiotic in patient with CBC resulted in a significant reduction (P < 0.05) in the number of thioglycolate positive cultures (<or= 60%) compared to non-treated eyes (>or= 88%). Following a minimum of a 1-day application of antibiotic, the median colony-forming unit was 0-1 compared to 3-8 for eyes without antibiotic treatment (P < 0.05). Scrubbing of the eyelids did not provide further benefit compared to antibiotic treatment alone. CBC eyes have a significantly higher number of positive cultures than eyes without CBC. The application of topical 0.5% levofloxacin for at least 3 days provided a significant reduction in the number of positive cultures as well as the number of bacteria harbored on the conjunctival surface.