Clinical outcomes with besifloxacin ophthalmic suspension 0.6% in the treatment of bacterial conjunctivitis due to potentially consequential pathogens

Abstract

Purpose: Besifloxacin is a chlorofluoroquinolone approved for use in the treatment of bacterial conjunctivitis. This study assessed the clinical efficacy of besifloxacin ophthalmic suspension 0.6% against conjunctivitis infections caused by potentially consequential pathogens. Design: Post hoc analysis of clinical outcomes for patients with conjunctival infections due to Pseudomonas aeruginosa, Serratia marcescens, Neisseria spp., methicillin-resistant Staphylococcus aureus (MRSA), and methicillin-resistant Staphylococcus epidermidis (MRSE) who were treated with besifloxacin in four multicenter, double-masked, randomized clinical trials. Methods: Minimum inhibitory concentrations (MICs) of besifloxacin against potentially consequential pathogens were pooled. Clinical outcome data for patients treated with besifloxacin with baseline infections due to these pathogens were pooled and summarized. Bacterial eradication was defined as the absence of ocular bacterial species present at or above threshold at baseline. Results: A total of 1,317 patients had culture-confirmed bacterial conjunctivitis across the four studies, and 151 infections were due to the aforementioned pathogens (P. aeruginosa n=9; S. marcescens n=10; Neisseria spp. n=16; MRSA n=35; MRSE n=81). Among MRSA and MRSE infections, 48.3% demonstrated concurrent ciprofloxacin resistance (ciprofloxacin-resistant [CipR]-MRSA n=24; CipR-MRSE n=32). The MIC90 (MIC for 90% of isolates) for besifloxacin was 1 μg/mL for S. marcescens, 0.25 μg/mL for Neisseria spp., 0.06 μg/mL for both ciprofloxacin-sensitive MRSA and ciprofloxacin-sensitive MRSE, and 4 μg/mL for both CipR-MRSA and CipR-MRSE. Against P. aeruginosa, the MIC range was 1–4 μg/mL. Bacterial eradication rates in patients treated with besifloxacin were 100% by the first follow-up visit for infections due to P. aeruginosa, S. marcescens, and Neisseria spp. and 87.8% by the second follow-up visit for infections due to MRSA and MRSE. Conclusion: The use of besifloxacin ophthalmic suspension 0.6% in the treatment of conjunctival infections due to potentially consequential pathogens resulted in high rates of bacterial eradication.