Skin microbiome before development of atopic dermatitis: Early colonization with commensal staphylococci at 2 months is associated with a lower risk of atopic dermatitis at 1 year

Abstract

BackgroundDisease flares of established atopic dermatitis (AD) are generally associated with a low-diversity skin microbiota and Staphylococcus aureus dominance. The temporal transition of the skin microbiome between early infancy and the dysbiosis of established AD is unknown.MethodsWe randomly selected 50 children from the Cork Babies After SCOPE: Evaluating the Longitudinal Impact Using Neurological and Nutritional Endpoints (BASELINE) longitudinal birth cohort for microbiome sampling at 3 points in the first 6 months of life at 4 skin sites relevant to AD: the antecubital and popliteal fossae, nasal tip, and cheek. We identified 10 infants with AD and compared them with 10 randomly selected control infants with no AD. We performed bacterial 16S ribosomal RNA sequencing and analysis directly from clinical samples.ResultsBacterial community structures and diversity shifted over time, suggesting that age strongly affects the skin microbiome in infants. Unlike established AD, these patients with infantile AD did not have noticeably dysbiotic communities before or with disease and were not colonized by S aureus. In comparing patients and control subjects, infants who had affected skin at month 12 had statistically significant differences in bacterial communities on the antecubital fossa at month 2 compared with infants who were unaffected at month 12. In particular, commensal staphylococci were significantly less abundant in infants affected at month 12, suggesting that this genus might protect against the later development of AD.ConclusionsThis study suggests that 12-month-old infants with AD were not colonized with S aureus before having AD. Additional studies are needed to confirm whether colonization with commensal staphylococci modulates skin immunity and attenuates development of AD.

Staphylococcus aureus: Master Manipulator of the Skin

“…A prospective observational study of culturable skin bacteria of children from birth to age 2 has shown that S. aureus colonization precedes the onset of the disease (Meylan et al, 2017), while another recent bacterial metagenomic study before onset of AD has shown the bacterial community can be protective (Kennedy et al, 2017). Additionally, whole-genome sequencing of skin swabs from AD subjects has shown again that S. aureus is increased and clonal on AD skin and suggested these clones promote changes in the skin of mice (Byrd et al, 2017).…”

Atopic Dermatitis: Collegium Internationale Allergologicum (CIA) Update 2019

“…During acute flares, the microbial diversity significantly decreases, correlating with AD severity, while the proportion of S. aureus increases [109]. Early colonization with commensal staphylococci at age of 2 months has been observed to lower the risk of AD at 1 year [110]. Both dysbiosis and S. aureus promote inflammation in AD [111].…”

Staphylococcal Biofilms in Atopic Dermatitis

“…The distribution of microbial communities changes with gender, age, and fluctuations in immune status [41] and is also sensitive to changes in humidity or seasonal weather [42]. In contrast, birthing method and feeding method have little effect on the skin microbiome [43]. The composition of the skin microbiome varies widely between different skin sites, dependent in part on whether the skin site is dry, oily, or moist [40, 44••].…”

“…To assess the evolution of dysbiosis in the skin microbiome, a study was conducted to characterize the skin microbiome within the first 6 months of life. Colonization at the antecubital fossa with commensal staphylococcal species (e.g., S. epidermidis and S. cohnii ) at 2 months of age was associated with decreased incidence of AD at 1 year [43]. Children who had developed AD at 1 year of age showed a decrease in skin commensals, suggesting that these species are protective.…”

“…Children who had developed AD at 1 year of age showed a decrease in skin commensals, suggesting that these species are protective. Notably, S. aureus was not observed in any samples collected from infants before the onset of AD symptoms [43]. More studies are needed to assess when S. aureus colonization most commonly occurs and the implications it carries for inflammatory responses.…”