Effects of a Moisturizer Containing Colloidal Oatmeal and Filaggrin Technology on Staphylococcus Species In Vitro

April 2025 | Volume 24 | Issue 4 | 416 | Copyright © April 2025


Published online March 12, 2025

doi:10.36849/JDD.8706 

Cleo Whiting BAa*, Sara Abdel Azim MDa*, Nicolas Joly-Tonetti PhDb, Nadege Lachmann MSb, Adam Friedman MD FAADa

aDepartment of Dermatology, George Washington University School of Medicine and Health Sciences, Washington, DC
bGlobal Sensitive Skincare Faculty, Galderma SA, Lausanne, Switzerland

*Authors contributed equally

Abstract

The pathophysiology of atopic dermatitis (AD) is multifactorial, with genetic predisposition, environmental exposures, and dysbiosis of the skin microbiome all associated with disease activity. Colonization by Staphylococcus aureus (S. aureus) is specifically associated with AD, and modifying the skin microbiota through topical skincare products may play a role in AD management. A moisturizer containing colloidal oatmeal, a patented filaggrin technology, niacinamide, and tocopheryl acetate was assessed for its impact on the growth, biofilm formation, and bacterial mix adhesion of S. aureus and/or S. epidermidis on reconstructed human epidermis (RHE). Compared to control conditions, the bacterial growth and adhesion of S. aureus were decreased compared to S. epidermidis in the presence of the moisturizer. Additionally, the moisturizer did not significantly induce nor inhibit the formation of S. aureus biofilm relative to control. Overall, the moisturizer improved the growth ratio of Staphylococcus species, shifting the predominant species from pathogenic S. aureus to commensal S. epidermidis, which may be clinically beneficial in the management of AD.

J Drugs Dermatol. 2025;24(4):416-418. doi:10.36849/JDD.8706 

INTRODUCTION

Atopic dermatitis (AD) is a multifactorial disease associated with both genetic risk factors and environmental stimuli. AD is also associated with dysbiosis, notably increased colonization by Staphylococcus aureus, and the degree of colonization correlates with disease severity.1 Topical skincare products may be beneficial in improving bacterial diversity resulting from barrier dysfunction.2 

A moisturizer specifically designed for AD (Moisturizer 1642) containing colloidal oatmeal, a patented filaggrin technology (Restoraderm Technology™, sodium pyrrolidone carboxylic acid [PCA], and arginine), niacinamide, and tocopheryl acetate was evaluated for its effect on bacterial growth, biofilm formation, and bacterial mix adhesion on reconstructed human epidermis (RHE). 

MATERIALS AND METHODS

The growth of two bacteria strains (S. aureus and S. epidermidis) cultured without hydrocortisone or antibiotics at 37°C with 5% CO2 was evaluated in the absence (control) and presence of Moisturizer 1642 at 8 concentrations from 0.004% to 0.5% by measuring optical density (OD) at 600 nanometers (nm) kinetically for 24 hours. Bacterial enumeration and adhesion were measured by colony counting of untreated (control) and pre-treated RHE seeded with a bacterial mix of 50% S. aureus and 50% S. epidermidis (1.67x107 CFU/ml of each strain). Biofilm formation of S. aureus was performed according to the Helaly et al protocol3 and was assessed by the fixation of crystal violet measured by optical density at 590 nm. Experimental data was standardized to control for color interference with OD measurements. All experiments were performed in triplicate.

Statistical analyses were performed using Microsoft Excel and GraphPad PRISM software. The inter-group comparisons were performed using unpaired Student's t-tests.

RESULTS

Bacterial Growth

Individual growth curves for each bacterial strain showed that under control conditions (n=3), S. aureus and S. epidermidis growth plateaued after approximately 12 and 8 hours of incubation, respectively. Following treatment with Moisturizer 1642 (n=3), no significant inhibition or promotion of either bacterial strain was observed. 

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