Bacteriotherapy Has Therapeutic Potential in Atopic Dermatitis-Related S. Areus

A personalized topical cream applied for 1 week was shown to reduce Staphylococcus areus colonization and improve clinical outcomes.

Bacteriotherapy formulated from coagulase-negative Staphylococcus can likely help combat Staphylococcus aureus (S. areus) colonization in patients with atopic dermatitis.

Research has long shown an association between atopic dermatitis and S. areus, which can lead to diminished expression of human skin antimicrobial peptides and defects in the skin barrier.

“Recently, we have found that an abnormality in the composition and function of the microbiome in patients with AD also contributes to S. areus overgrowth,” noted the investigative team, led by Teruaki Nakatsuji, PhD, of the University of California, San Diego.

“Compared with individuals without AD, patients with AD lack coagulase-negative Staphylococcus (CoNS) that has the capacity to produce antimicrobials (AM) that inhibit SA (CoNS-AM+),” they continued.

Nakatsuji and colleagues thus conducted a randomized, double-blind, placebo-controlled study to explore the potential efficacy and safety of autologous CoNS-AM+ application for 1 week.

The Study

The team isolated CoNS-AM+ from the nonlesional skin of patients randomized to active treatment (n = 5), expanded the isolates through culture and formulated it in Cetaphil lotion. Patients in the vehicle cohort (n = 6) received cream formulated with saline only.

Twice a day for 7 days, they then applied 2 grams of either lotion on the ventral surface of the arms, which included lesional and nonlesional areas.

They obtained skin swab results at day 0, day 4, day 7, 8, 9, and 11.

As such, the primary endpoint sought by the investigators was the abundance of S. aureus after 1 week. Secondary endpoints included safety and clinical outcomes.

The Results

“Species characterization of each individual CoNS-AM+ isolate revealed a variety of different strains with AM activity, including Staphylococcus epidermidis, Staphylococcus hominis, Staphylococcus warneri, and Staphylococcus capitis,” Nakatsuji’s team reported. “These strains show potent AM activity against the SA strain that was isolated from the lesional skin of the same patient.:

Overall, there were no serious adverse events observed in either treatment group.

The team also noticed that S. aureus colonization was reduced by 99.2% in patients treated with the autologous CoNS-AM+ (mean of log10 ratio to baseline, −1.702; 95% CI, −2.882 to −0.523) when compared with vehicle treatment (mean of log10 ratio to baseline, 0.671; 95% CI, −0.289 to 1.613; P = .01). This improvement notably persisted for 4 days post-treatment.

Furthermore, patients who received CoNS-AM+ treatment (mean of percentage change, −48.45; 95% CI, −84.34 to −12.55) experienced significant improvements in local Eczema Area and Severity Index (EASI) scores at day 11 when compared with those who received vehicle treatment (mean of percentage change, −4.52; 95% CI, −36.25 to 27.22; P = .04).

The team acknowledged the single-center nature of the study and the small cohort as limitations of their study — nevertheless, they expressed optimism for bacteriotherapy’s potential against S aureus in this patient population.

“Early results from this study, as well as others, demonstrate promise for bacteriotherapy that utilizes protective skin commensal microbes in AD,” they concluded. “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.”

The study, “Use of Autologous Bacteriotherapy to Treat Staphylococcus aureus in Patients With Atopic Dermatitis: A Randomized Double-blind Clinical Trial,” was published online in JAMA Dermatology.