The diversity and host interactions of Propionibacterium acnes bacteriophages on human skin.
Liu J, Yan R, Zhong Q, et al. ISME J. 2015 Apr 7. [Epub ahead of print]
The investigators sought to determine whether bacteriophages modulate the composition of the bacterial populations, thus potentially playing a role in health or disease. By sequencing 48 P. acnes phages isolated from acne patients and healthy individuals and by analyzing the P. acnes phage populations in healthy skin metagenomes, they found that P. acnes phage populations in the skin microbial community are often dominated by one strain. It was also found that phage strains shared among both related and unrelated individuals, suggesting that a pool of common phages exists in the human population and that transmission of phages may occur between individuals. To better understand the bacterium-phage interactions in the skin microbiota, the authors determined the outcomes of 74 genetically defined Propionibacterium strains challenged by 15 sequenced phages. In type II P. acnes strains, they found that encoding matching clustered regularly interspaced short palindromic repeat spacers is insufficient to confer phage resistance. Overall, the findings suggest that the prey-predator relationship between bacteria and phages may have a role in modulating the composition of the microbiota. The study also suggests that the microbiome structure of an individual may be an important factor in the design of phage-based therapy.