Analysis of Complete Genomes ofPropionibacterium acnesReveals a Novel Plasmid and Increased Pseudogenes in an Acne Associated Strain

Abstract

The human skin harbors a diverse community of bacteria, including the Gram-positive, anaerobic bacteriumPropionibacterium acnes.P. acneshas historically been linked to the pathogenesis of acne vulgaris, a common skin disease affecting over 80% of all adolescents in the US. To gain insight into potentialP. acnespathogenic mechanisms, we previously sequenced the complete genome of aP. acnesstrain HL096PA1 that is highly associated with acne. In this study, we compared its genome to the first published complete genome KPA171202. HL096PA1 harbors a linear plasmid, pIMPLE-HL096PA1. This is the first describedP. acnesplasmid. We also observed a five-fold increase of pseudogenes in HL096PA1, several of which encode proteins in carbohydrate transport and metabolism. In addition, our analysis revealed a few island-like genomic regions that are unique to HL096PA1 and a large genomic inversion spanning the ribosomal operons. Together, these findings offer a basis for understandingP. acnesvirulent properties, host adaptation mechanisms, and its potential role in acne pathogenesis at the strain level. Furthermore, the plasmid identified in HL096PA1 may potentially provide a new opportunity forP. acnesgenetic manipulation and targeted therapy against specific disease-associated strains.