Bifidobacteria spp.119-120 Theoretically, introduction of these species may mitigate and outcompete pathogenic organisms,121 thereby improving CM homeostasis.
Several clinical trials have found success in using probiotics as monotherapy or in conjunction with traditional AV therapy (Table 3).119,122-127 Studies are investigating "grafting" autologous microbes cultured from non-lesional skin in individuals with dermatoses onto affected areas.128 In the future, we may be able to extract the contents of an AV-prone follicle, apply a cocktail of C. acnes (IA1)-specific bacteriophage to deplete pathogenic strains and reintroduce commensal C. acnes phylotypes II and III.42,62 This dual-pronged approach may provide a personalized, targeted means to improve disease severity while promoting a healthy CM.129
More than Moisture: Water, Prebiotics, and Postbiotics
Prebiotics are topical/oral supplements or foods that selectively support and stimulate the growth and/or activity of the microbiome.
Different microorganisms have been found to tolerate decreased SCH, such as S. aureus, whose abundance correlates temporally with AD flares,130 and therefore may outcompete commensal microbes under more "arid" conditions.12,131 Therefore adequate moisturization and water-retention may not only promote EBF but also microbiome diversity. In this way water, by cultivating and stimulating CM growth and/or activity, may be considered a prebiotic.132
Postbiotics (or bacterial byproducts, metabolites, and excreted compounds from lysed organisms, such as Xanthomonas, and Enterococcus faecalis) may also have potential to affect dermatoses. An 8-week double-blind, randomized, vehiclecontrolled trial of 70 mild-moderate AV patients found that topically-applied anti-bacterial isolate from fecal Enterococcus faecalis significantly (P<.05) reduced more pustules than the vehicle.123 Postbiotics from Vitreoscilla filiformis, a gramnegative filamentous, non-pathogenic bacterium that is naturally found in thermal springs and spa water133 has been found to have antioxidant abilities mediated via mitochondrial superoxide dismutase in vitro134 and anti-inflammatory activity via interleukin-10 (IL-10) mediated regulatory T cells within murine models of AD.135 Preliminary data also suggest that addition of V. filiformis lysate to emollients may provide a method to improve EBF and CM diversity.136-138
DISCUSSION AND FUTURE DIRECTIONS
While the flow of causality between EBD and dysbiosis is
not yet clear for AV and rosacea, they do appear to play a
material role in the pathogenesis and development of clinical
symptoms. Repairing the barrier and restoring the microbiome
are essential, and quality skin care may help patients achieve
this goal. It is vital that dermatologists are aware of the growing
