The Antibacterial Comparison of 5% and 2.5% Povidone Iodine to 0.01% Hypochlorous Acid Using Corneoscleral Tissue as a Solid-Phase Medium

Abstract

Purpose

Prophylactic topical antiseptics used to eliminate bacteria on the ocular surface prior to ocular surgery should be both effective and non-irritating. Five percent povidone iodine (PI) is an accepted antiseptic used for prophylaxis. Dilute 2.5% PI and 0.01% hypochlorous acid (HOCl) may be more patient comfortable and equally effective. PI at 5% and 2.5% were compared to HOCl against a battery of bacterial endophthalmitis isolates using corneoscleral tissue as a solid-phase medium to determine antiseptic efficacy.

Methods

Bacteria from 20 cases of endophthalmitis were tested for the elimination of growth against topical 5% PI, 2.5% PI, HOCl, and no antiseptic using donor corneoscleral tissue. The tissue was inoculated with 10³ colony forming units of bacteria prior to a 3-minute contact time with the antiseptics, placed in liquid growth medium, and monitored for growth at three days. No growth indicated antiseptic treatment success. Differences were analyzed using Chi square (χ2).

Results

For 20 isolates, 5% PI was comparable to 2.5% PI for preventing bacteria growth (p=0.71), and both were more effective than HOCl (p=0.004). Estimated weighted comparison over a 27-year period indicated that for all bacterial groups, except Streptococcus viridans, 5% PI was equally effective to 2.5% PI for preventing bacterial growth (p=1.0). For Streptococcus viridans, 5% PI was more effective than 2.5% PI (p=0.0001). Both concentrations of PI were more effective than HOCl (p=0.00001).

Conclusion

Five percent PI appears to be optimal as a prophylaxis prior to ocular surgery.

Keywords:

• povidone iodine
• hypochlorous acid
• endophthalmitis prophylaxis
• intravitreal injection
• corneoscleral tissue
• antiseptic susceptibility

Disclosure

Dr Michelle Rhee reports grants from Ocular Therapeutix, is a Medical Advisor Board member for NovaBay, and consultant for The Eye-Bank for Sight Restoration, outside the submitted work. Dr Deepinder Dhaliwal reports personal fees from Kala, personal fees from Trefoil, personal fees from Haag Streit, personal fees from Horizon Therapeutics, personal fees from Ocular Therapeutics, personal fees from Novartis, personal fees from Allergan, personal fees from Staar Surgical, grants from Noveome, grants from Avedro, grants from Kowa, outside the submitted work. The authors have no current “Significant Conflict of Interests” to disclose for the completion of this study as determined by the Office of Research, University of Pittsburgh, Pittsburgh, PA, USA.

Additional information

Funding

This study was partially supported by the Eye Bank Association of America/Richard Lindstrom Research Grant. This work was supported by NIH CORE Grant P30 EY08098 to the Department of Ophthalmology, the Eye and Ear Foundation of Pittsburgh, and from an unrestricted grant from Research to Prevent Blindness, New York, NY.