Skin Microbiome in Patients With Psoriasis Before and After Balneotherapy at the Thermal Care Center of La Roche-Posay

December 2015 | Volume 14 | Issue 12 | Original Article | 1400 | Copyright © December 2015

Richard Martin MSc,a Jessica B. Henley PhD,b Patrick Sarrazin MD,c and Sophie Seité PhDd

aL’Oréal Research and Innovation, Tours, France
bCooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
cThermal care center La Roche-Posay, La Roche-Posay, France
dLa Roche-Posay Dermatological Laboratories, Asnières, France

BACKGROUND: Changes in the composition of microbial communities that colonize skin have been linked to several diseases including psoriasis. Nevertheless, the intra-individual dynamics and how these communities respond to balneotherapy remain poorly understood.
METHODS: This open label study was conducted between July and September 2012. Microbial communities of patients with psoriasis vulgaris were characterized prior and post a 3-week selenium-rich water balneotherapy treatment at the thermal care center La Roche-Posay (La Roche-Posay, France). Balneotherapy consisted of high-pressure filiform showers, baths, facial, and body spray treatments as well as La Roche-Posay thermal spring water (LRP-TSW) consumption. Swabs were taken from affected and proximal unaffected skin and the 16S rRNA bacterial gene was used to analyze the composition of bacterial communities. Using the same 16S rRNA gene tool, we tried to describe the LRP-TSW bacterial landscape.
RESULTS: This study included 54 patients diagnosed with moderate to severe forms of psoriasis vulgaris. After eliminating individuals lacking paired samples from both visits, 29 individuals were analyzed for their microbiome profile. Shannon Diversity Index and global bacterial landscape indicate similar microbial communities on both unaffected and adjacent affected skin. PASI values decreased post-balneotherapy implying improvement of disease severity. No significant change in the Shannon Diversity Index was noticed at the end of the third week. The average taxonomic composition of skin microbial communities associated with unaffected and affected skin of psoriatic patients post-balneotherapy shows that treatment with LRP-TSW significantly increased the level of Xanthomonas genus and, to a lesser extent, Corynebacterium genus. The Xanthomonas genus belongs to the main Xanthomonadaceae family found in LRP-TSW and also on healthy skin.
CONCLUSIONS: In psoriatic patients, a poor bacterial biodiversity was noticed and the bacterial communities were similar on unaffected and affected adjacent skin. Family analysis identified, for the first time, Xanthomonadaceae belonging to Proteobacteria phylum and known to be keratolytic, associated with the clinical improvement observed after a 3-week balneotherapy treatment. This data supports the interest of selenium-rich thermal spring water in the treatment of psoriasis vulgaris.

J Drugs Dermatol. 2015;14(12):1400-1405.


Human skin hosts complex microbial communities whose diversity and composition vary by skin region1 and between individuals.2,3 Compositional differences between skin regions arise largely from contrasting environmental conditions of skin sites.4 Inter-individual differences in microbiome composition have been attributed to a number of factors including host genetics, demographics and behavior.5 For example, the diversity of palm bacterial communities differs between genders.6 These inter- and intra-individual differences in skin bacterial communities may contribute to differences in disease susceptibility and quantifying such differences may help to monitor changes in skin health status.7,8
Many clinical therapeutic usages of selenium-rich water balneotherapy treatment at the thermal care center La Roche-Posay including mainly chronic inflammatory diseases ie, atopic dermatitis (eczema), psoriasis but also, wound healing, burn scars, pruritus, and others dermatosis like rosacea or ichthyosis have been widely described.9 In the past, thermal spring water was only described by its mineral composition and never by its natural bacterial signature.10 Thermal spring water, used in the different treatments, is non-sterile water that contains its own bacterial profile. Due to the specificity of water biotope, bacterial signature must be very reproducible and is linked to the mineral signature of each thermal spring water.
In a clinical study previously performed on 92 patients with moderate plaque psoriasis undergoing a selenium-rich water balneotherapy showed that after 3 weeks of treatment, PASI score (Psoriasis Area and Severity Index score)11 was reduced by 47% ± 4% (P<0.001). Interestingly, 8% of patients were completely cleared and 48% improved by more than 50%. Prior to