Reducing S aureus Skin Colonization in Patients With AD

A close-up of bad psoriasis on a person’s arm
Can treatment with autologous CoNS-AM+ suppress S. aureus survival and improve atopic dermatitis symptoms?

Reintroduction of autologous antimicrobial-producing coagulase-negative Staphylococcus (CoNS-AM+) to patients with atopic dermatitis (AD) was associated with a reduction in the colonization of S. aureus and improved disease severity, according to study findings published in JAMA Dermatology.

Investigators in the double-blind, single-center study randomly assigned adult patients with moderate to severe AD to receive either autologous CoNS-AM+ (n=5) or a vehicle control (n=6).

In the group that received active intervention, researchers isolated autologous CoNS-AM+ from swabs obtained from nonlesional skin of each patient with AD. The CoNS-AM+ was then expanded by culture and reapplied to each assigned patient’s forearm skin at a concentration of 107 colony-forming units/gram. Researchers compared groups at 1 week in terms of S. aureus abundance. Safety and clinical outcomes were also assessed at the 1-week follow-up period.

No serious adverse events were reported in either treatment arm. At the completion of treatment, colonization of S. aureus on lesional skin in patients who received autologous CoNS-AM+ (mean of log10 ratio to baseline, −1.702; 95% CI, −2.882 to −0.523) was reduced by 99.2% compared with that observed in the vehicle control arm (mean of log10 ratio to baseline, 0.671; 95% CI, −0.289-1.613; P =.01). This reduction was maintained for up to 4 days following treatment (CoNS-AM+, mean of log10 ratio to baseline, −1.752; 95% CI, −3.051 to −0.453; vehicle, mean of log10 ratio to baseline, −0.003; 95% CI, −1.083 to 1.076; P =.03).

At day 11, changes in the local Eczema Area And Severity Index scores in the CoNS-AM+ group (mean of percentage change, −48.45; 95% CI, −84.34 to −12.55) were significantly improved compared with the change in the vehicle control arm (mean of percentage change, −4.52; 95% CI, −36.25-27.22; P =.04).

Limitations of this study included its single-center design, small sample size, and the inclusion of only adults with S. aureus-positive AD.

The researchers wrote that “future investigations that target the microbiome in AD represent a therapeutic approach that may alter the pathogenesis of AD and explore its potential as an early intervention in pediatric AD.”


Nakatsuji T, Gallo RL, Shafiq F, et al. Use of autologous bacteriotherapy to treat staphylococcus aureus in patients with atopic dermatitis: A randomized double-blind clinical trial. Published online June 16, 2021. JAMA Dermatol. 2021;157(8):978-982. doi:10.1001/jamadermatol.2021.1311