Effect of an Emollient on the Mycobiome of Atopic Dermatitis Patients
October 2018 | Volume 17 | Issue 10 | Original Article | 1039 | Copyright © October 2018
Jyotsna Chandra PhD,a Mauricio Retuerto BS,a Sophie Seité PhD,b Richard Martin PhD,c Michaela Kus BS,a Mahmoud A. Ghannoum PhD,a Elma Baron MD,a,d Pranab K. Mukherjee PhDa
aCenter for Medical Mycology, Department of Dermatology, Case Western Reserve University, Cleveland, OH bLa Roche-Posay Dermatological Laboratories, Levallois-Perret, France cL’Oréal Research and Innovation, Tours, France dVeterans Affairs Medical Center, Cleveland, OH
INTRODUCTION: Atopic dermatitis (AD) is associated with changes in skin bacterial microbiome. Emollient treatment induces change in bacterial microbiome in AD, but its effect on fungal microbiome (“mycobiome”) and their inter-kingdom correlations is unknown. We used Ion-Torrent sequencing to characterize the mycobiome of AD patients in response to emollient treatment.
METHODS: Skin swabs were collected from lesional and non-lesional skin of AD patients suffering from moderate AD, after informed consent and according to GCP guidelines. Genomic DNA was extracted from each swab using the MoBio PowerSoil DNA Isolation kit and used for mycobiome sequencing analyses as described in our earlier publications. Principal coordinates analyses (PCoA), diversity, abundance, and correlations analyses were conducted in R and relevant packages using non-parametric tests (P less than .05 was significant).
RESULTS: Swab samples from 10 patients (7 females, 3 males; mean age, 10.5 years) were analyzed. Emollient treatment induced a significant reduction of Scoring Atopic Dermatitis (SCORAD) score (P less than .001). PCoA showed pre-treatment and post-treatment samples clustered differently at all taxa levels. Six genera were detected in only non-lesional samples, while four were detected in only lesional samples. In non-lesional samples, Shannon diversity index was significantly increased after emollient treatment (P less than equal to .04), while lesional skin exhibited non-significant decrease. Ascomycota was the most abundant phylum and Dothideomycetes was the most abundant Class in most samples. Eight fungal species were either significantly different (P less than .05) or showed a strong trend (P less than .1) between pre- and post-treatment samples of lesional and non-lesional skin. In lesional skin, Gram-negative Pseudomonas spp. correlated significantly with pathogenic fungal species (Aspergillus, Candida spp.) in pre-treatment samples; these correlations were not detected in post-treatment samples. Moreover, lesional skin exhibited significant correlations between Gram-positive bacteria (Corynebacterium kroppenstedtiian and Staphylococcus pettenkoferi) and pathogenic Candida species in pre-treatment samples, but not in post-
DISCUSSION: Emollient treatment may induce beneficial microbial changes in the mycobiome and augment host-microbe balance on skin in AD. Clinical relevance of these results need to be investigated.
J Drugs Dermatol. 2018;17(10):1039-1048.
Atopic dermatitis (AD) is a chronic inflammatory skin disorder that results in areas of dry, itchy skin.1,2 Several cultivation-dependent and independent studies have identified changes in the composition of microbial communities in these affected areas over time and when compared to healthy control individuals.3-8 However, how these communities vary on affected and unaffected skin of the same individual, and how these communities respond to treatment, remains poorly understood.In a previous study, Flores et al9 characterized the bacterial microbiota of affected and unaffected skin of 49 patients with AD before and after emollient treatment using high-throughput sequencing V1-V2 areas of the 16S rRNA gene. These investigators showed that microbial diversity and community composition was different between affected and unaffected skin of AD patients prior to treatment. Differences were driven primarily by the overabundance of Staphylococcus species on affected skin and a corresponding decrease in bacterial diversity. After 3 months of emollient treatment, the clinical symptoms of AD improved in 72% of the study population and an average decreased SCORAD of -38% (from 34 to 21) was noted. Microbial communities associated with affected skin of these treatment responders more closely resembled unaffected skin after treatment as indicated by increased overall diversity and a decrease in the abundance of Staphylococcus species without any antibiotic treatment. Interestingly, Xanthomonas genus was signifi-