May 03, 2016
2 min read

Study: Hypochlorous acid eliminates nearly all staph from lower lids

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SEATTLE – Saline containing 0.01% pure hypochlorous acid was found to reduce Staphylococcus overall from the skin below the eyelid in 99.6% of ocular specimens, according to David W. Stroman, PhD.

“This is the first clinical study with a product many of you know as Avenova (NovaBay),” Stroman said here at the Association for Research in Vision and Ophthalmology meeting.

He said the challenge for the clinician is to reduce the load of bacteria and other microbes from the surface of the skin as much as possible.

“It’s erroneous to think we could ever sterilize the skin, because many of the bacteria are in the sweat glands and epidermidis, but you can reduce bacteria on the surface.”

Stroman and colleagues collected 71 microbiological specimens from the eyelids of 36 subjects before and 20 minutes after an application of hypochlorous acid. Average patient age was 63 years, with a range of 19 years to 88 years. There were 22 females and 14 males, he said.

The most common bacterial species collected was Staphylococcus, Stroman reported, with Propionibacterium as the second most common. Others included Corynebacterium, Bacillus, Enterococcus, Micrococcus, Rothia, Streptococcus mitis, Prevotella, Pseudomonas, Pantoea, Neisseria, Moraxella and Enterobacter.

“The majority collected were gram-positive species, and 20 minutes later the mix hasn’t changed much at all, it’s just that the amount has changed,” Stroman said.

“This is an important concept,” he continued. “Some people worry about treatment with agents on the surface of the skin, that you may disturb the diversity of bacteria present.”

Ninety-eight strains of staphylococci were recovered prior to treatment, and 24 were identified 20 minutes after treatment, Stroman said.

Of these 98 strains of staphylococci, 60 were Staphylococcus epidermidis, he said, and only 18 were left 20 minutes after treatment.

Stroman said he is still completing the analysis of P. acnes, the second most common.

“So far there’s a 93% reduction, but I expect it to go down,” he said.

Overall, total staphylococci recovered were reduced by 99.6% 20 minutes after treatment with hypochlorous, Stroman said.

However, there is “more to this story,” he said. “There were other strains of these species that appeared 20 minutes after hypochlorous acid treatment that we did not recover at time 0. We recovered 54 gram-positive isolates at 20 minutes that were not present at time 0. Also, 31 strains of S. epidermidis were not originally present.”

Stroman said perhaps the sample was taken at a different spot or some were uncovered that had been down in the epidermis or hair follicle.

“We can’t ignore that; you’re not sterilizing the surface of the skin,” he said. “If you look at the same type of susceptibility profile, they’re no different than the others we saw at time 0.”

Stroman concluded: “The skin near the lid margin will be recolonized rapidly after a hypochlorous acid treatment even though it removes many of them. For that reason, we encourage users of our product to treat multiple times per day to optimally reduce the load at the surface of the skin.”

He said further research will assess the diversity and bacterial load after 2 weeks of twice daily treatment. – by Nancy Hemphill, ELS, FAAO


Stroman DW, et al. Reduction in the bacterial load on the skin in a clinical setting. Presented at: ARVO; May 1-5, 2016; Seattle, Washington.

Disclosure: Stroman is employed by NovaBay Pharmaceuticals.