Abstract
Purpose :
We compared the antibacterial activity of povidone iodine (PI) and hypochlorous acid (HA) against endophthalmitis isolates of Staphylococcus aureus and coagulase-negative staphylococcus using time-kill studies.
Methods :
Time-kill studies of PI, HA (0.08%), and HA (0.01%, Avenova), were conducted in duplicate against methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant Staphylcoccus aureus (MRSA), and coagulase negative Staphylococcus (CNS) at time points 1, 2, 10, and 30 minutes. Each antiseptic was inoculated to a final bacterial concentration of 106 CFU/mL. The main outcome measure was based on a bactericidal decrease in colony counts units (CFU) (3 log10 or 99.9% decrease).
Results :
At 1 minute, HA (0.08% and 0.01%) were more bactericidal than PI for decreasing the CFU of MRSA, MSSA, and CNS (p=0.045, Fisher’s Exact Test). At 2 minutes, the bactericidal effect was equivalent for PI and HA (0.08% and 0.01%) against the three Staphylococcal groups. The bactericidal effects of HA 0.08% and HA 0.01% were equivalent at all time points against all three Staphylococcal groups.
Conclusions :
Povidone iodine is the current gold standard for endophthalmitis prophylaxis. This in vitro study supports a 2 minute contact time between Staphylococci and PI for a bactericidal effect. The contact time between HA (0.08% and 0.01%) and Staphylococci for a bactericidal effect appears to be reduced to 1 minute.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.