Comparative antibacterial activity of topical antiseptic eardrops against methicillin-resistant Staphylococcus aureus and quinolone-resistant Pseudomonas aeruginosa

Objective: Aural irrigation using antiseptic solutions can be an effective medical treatment of chronic suppurative otitis media (CSOM) owing to the increasing prevalence of antibiotic-resistant CSOM infections. In the present study, we compared the antimicrobial activities of 100% Burow's solution, 50% Burow's solution, 2% acetic acid, vinegar with water (1:1), and 4% boric acid solution against methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible S. aureus (MSSA), quinolone-resistant Pseudomonas aeruginosa (QRPA), and quinolone-susceptible P. aeruginosa (QSPA) in vitro. Methods: We examined the antimicrobial activities of five antiseptic solutions against MRSA, MSSA, QRPA, and QSPA. The antimicrobial activities of the solutions were calculated as a percentage of the surviving microorganisms by dividing the viable count in each antiseptic solution with that in control. The time (D-10 value) required for each of the five solutions to inactivate 90% of the microorganism population was also investigated. Results: Burow's solution exhibited the highest antimicrobial activity and the lowest D10 value against MRSA, MSSA, QRPA, and QSPA, followed by 2% acetic acid, vinegar with water (1:1), and 4% boric acid solution. Conclusion: Our results indicate that Burow's solution has the most potent activity against bacteria including antibiotic-resistant strains. Twofold dilution of the solution is recommended to avoid ototoxicity. (C) 2016 Elsevier Ireland Ltd. All rights reserved.