Phylogenetic Type III is Associated with Progressive Macular Hypomelanosis.

Progressive macular hypomelanosis (PMH) is a skin disorder that is characterized by hypopigmented macules and usually seen in young adults. The skin microbiota, in particular the bacterium , is suggested to play a role. Here, we compared the population of 24 PMH lesions from eight patients with corresponding nonlesional skin of the patients and matching control samples from eight healthy individuals using an unbiased, culture-independent next-generation sequencing approach. We also compared the population before and after treatment with a combination of lymecycline and benzoylperoxide. We found an association of one subtype of , type III, with PMH. This type was predominant in all PMH lesions (73.9% of reads in average) but only detected as a minor proportion in matching control samples of healthy individuals (14.2% of reads in average). Strikingly, successful PMH treatment is able to alter the composition of the population by substantially diminishing the proportion of type III. Our study suggests that type III may play a role in the formation of PMH. Furthermore, it sheds light on substantial differences in the phylotype distribution between the upper and lower back and abdomen in healthy individuals.