title: An expanded multilocus sequence typing scheme for propionibacterium acnes: investigation of 'pathogenic', 'commensal' and antibiotic resistant strains.
abstract: 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 (http://pubmlst.org/pacnes). 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.
authors.affiliation: Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University, Belfast, United Kingdom. a.mcdowell@qub.ac.uk
authors.forename: Andrew
authors.initials: A
authors.lastname: McDowell
authors.forename: Emma
authors.initials: E
authors.lastname: Barnard
authors.forename: István
authors.initials: I
authors.lastname: Nagy
authors.forename: Anna
authors.initials: A
authors.lastname: Gao
authors.forename: Shuta
authors.initials: S
authors.lastname: Tomida
authors.forename: Huiying
authors.initials: H
authors.lastname: Li
authors.forename: Anne
authors.initials: A
authors.lastname: Eady
authors.forename: Jonathan
authors.initials: J
authors.lastname: Cove
authors.forename: Carl E
authors.initials: CE
authors.lastname: Nord
authors.forename: Sheila
authors.initials: S
authors.lastname: Patrick
mesh_terms: D000152:Acne Vulgaris / Q000382:microbiology; D015373:Bacterial Typing Techniques; D030541:Databases, Genetic; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D009877:Endophthalmitis / Q000382:microbiology; D019143:Evolution, Molecular; D005798:Genes, Bacterial; D020043:Genes, Essential; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology; D006801:Humans; D007634:Keratitis / Q000382:microbiology; D015810:Linkage Disequilibrium; D058885:Multilocus Sequence Typing; D009154:Mutation; D010802:Phylogeny; D011425:Propionibacterium acnes / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D012329:RNA, Bacterial / Q000235:genetics; D012335:RNA, Ribosomal / Q000235:genetics; D012641:Selection, Genetic; D012867:Skin / Q000382:microbiology; D037521:Virulence Factors / Q000235:genetics
chemical_list: D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D037521:Virulence Factors