Yin and Yang of skin microbiota in "swimmer acne".

Cutibacterium acnes (C. acnes) is an organism implicated in the pathogenesis of acne. Despite regular immersion in antimicrobial chlorine, adolescent swimmers suffer from acne and tend to be resistant to standard therapies. Given the presence of Pseudomonas within swimming facilities, we hypothesized that "swimmer acne" is potentially driven by a different microbial mechanism. In this study, we aimed to examine the microbial dynamics of C. acnes and Pseudomonadaceae, a family of gram-negative bacteria (includes Pseudomonas aeruginosa), in swimmers and its potential contribution to the pathogenesis of acne in this population. Using fluorescence photography that measures the Coproporphyrin III (CPIII), we quantitated an absolute abundance of C. acnes present on the face of each participant pre- and post-swimming. In addition, 16S rRNA gene sequencing was utilized to assess relative abundance of the skin microbiota on each participant pre- and post-swimming. 16 swimmers (8 girls and 8 boys) completed the study. Seven had acne on the face. The CPIII fluorescence levels decreased for all swimmers after 1 h of swimming (p-value <0.001). In contrast, the relative abundance of C. acnes remained unchanged, while that of Pseudomonadaceae increased after swimming (p-value =0.027). Comparing the relative abundances of Pseudomonadaceae before swimming, there was a significant increase in variance from the mean in acne group as compared to no acne group (p-value <0.001). Taken together, we conclude that the skin dysbiosis resulting from repeated decolonization and colonization of C. acnes and Pseudomonadaceae, respectively, can potentially be associated with the pathogenesis of acne in swimmers.

Effects of swimming on facial sebum in adolescents.

Swimmers often complain of dry skin, consistent with decreased skin sebum levels, and yet may also have acne, which is commonly related to elevated sebum levels. Sixteen adolescent swimmers with and without acne were enrolled to examine two markers of facial sebum levels before and after 1 hour of swimming. Swimmers with acne did not have significant decreases in their sebum levels or shine measurements after swimming, whereas swimmers without acne did. Overall, swimming may remove superficial sebum more than follicular sebum and therefore leave swimmers subject to both dry skin and acne simultaneously.

Accessibility to air travel correlates strongly with increasing melanoma incidence.

As the cost of air travel has decreased substantially in the USA and Europe over the past few decades, leisure travel to vacation destinations during the winter months has expanded significantly. This trend has probably increased the incidence of significant ultraviolet radiation exposure and sunburn in a broader population who could not previously afford this kind of travel. The purpose of this study was to analyse the correlation between increasing accessibility to air travel and melanoma incidence. This ecological study surveyed air travel patterns and melanoma incidence over the past three decades. Melanoma age-adjusted incidence was obtained from the United States Surveillance, Epidemiology, and End Results 9 Registry Database, 1975-2000, and the Cancer Registry of Norway, 1965-2000. United States mean inflation-adjusted airfare prices for four airports linked to leisure destinations (Miami, Los Angeles, San Diego, Phoenix) were compared with melanoma incidence. Parallel analyses were performed using annual domestic passenger-kilometres and melanoma incidence in Norway. Declining United States leisure-specific airfares corresponded strongly with increasing melanoma incidence (r = 0.96, r = 0.92, P < 0.001). Modelling a 5-year time lag between airfare and melanoma diagnosis strengthened the association (r = 0.98, r = 0.96, P < 0.001). Longer time lags could not be modelled due to data limitations. Data from Norway similarly showed that increasing air passenger mileage corresponded strongly with increasing melanoma incidence. Although correlation does not equate to causality, the very strong relationship between increasing access to air travel and melanoma incidence suggests that changes in recreational patterns may be contributing significantly to the public health problem of melanoma.