An expanded multilocus sequence typing scheme for propionibacterium acnes: investigation of 'pathogenic', 'commensal' and antibiotic resistant strains

PLoS One. 2012;7(7):e41480. doi: 10.1371/journal.pone.0041480. Epub 2012 Jul 30.


The Gram-positive bacterium Propionibacterium acnes is a member of the normal human skin microbiota and is associated with various infections and clinical conditions. There is tentative evidence to suggest that certain lineages may be associated with disease and others with health. We recently described a multilocus sequence typing scheme (MLST) for P. acnes based on seven housekeeping genes ( We now describe an expanded eight gene version based on six housekeeping genes and two 'putative virulence' genes (eMLST) that provides improved high resolution typing (91eSTs from 285 isolates), and generates phylogenies congruent with those based on whole genome analysis. When compared with the nine gene MLST scheme developed at the University of Bath, UK, and utilised by researchers at Aarhus University, Denmark, the eMLST method offers greater resolution. Using the scheme, we examined 208 isolates from disparate clinical sources, and 77 isolates from healthy skin. Acne was predominately associated with type IA(1) clonal complexes CC1, CC3 and CC4; with eST1 and eST3 lineages being highly represented. In contrast, type IA(2) strains were recovered at a rate similar to type IB and II organisms. Ophthalmic infections were predominately associated with type IA(1) and IA(2) strains, while type IB and II were more frequently recovered from soft tissue and retrieved medical devices. Strains with rRNA mutations conferring resistance to antibiotics used in acne treatment were dominated by eST3, with some evidence for intercontinental spread. In contrast, despite its high association with acne, only a small number of resistant CC1 eSTs were identified. A number of eSTs were only recovered from healthy skin, particularly eSTs representing CC72 (type II) and CC77 (type III). Collectively our data lends support to the view that pathogenic versus truly commensal lineages of P. acnes may exist. This is likely to have important therapeutic and diagnostic implications.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acne Vulgaris / microbiology
  • Bacterial Typing Techniques
  • Databases, Genetic
  • Drug Resistance, Bacterial / genetics*
  • Endophthalmitis / microbiology
  • Evolution, Molecular
  • Genes, Bacterial
  • Genes, Essential
  • Gram-Positive Bacterial Infections / microbiology
  • Humans
  • Keratitis / microbiology
  • Linkage Disequilibrium
  • Multilocus Sequence Typing*
  • Mutation
  • Phylogeny
  • Propionibacterium acnes / classification
  • Propionibacterium acnes / genetics*
  • Propionibacterium acnes / isolation & purification
  • RNA, Bacterial / genetics
  • RNA, Ribosomal / genetics
  • Selection, Genetic
  • Skin / microbiology
  • Virulence Factors / genetics


  • RNA, Bacterial
  • RNA, Ribosomal
  • Virulence Factors

Grant support

The work was supported by funding from the R & D Office of the Health and Personal Social Services Northern Ireland (grant number HSCNI 9.41; and The Prostate Cancer Charity, United Kingdom (grant number 110831; IN: Hungarian National Office for Research and Technology Teller program OMFB-00441/2007, French-Hungarian Associated European Laboratory (LEA) SkinChroma OMFB-00272/2009, and TAMOP-4.2.1.B-10/2/KONV-2010-0002. AG: Micropathology Ltd and the Royal Commission for the Exhibition of 1851. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.