Downloaded from www.microbiologyresearch.org by IP: 54.70.40.11 On: Thu, 25 Oct 2018 10:11:51 A novel multilocus sequence typing scheme for the opportunistic pathogen Propionibacterium acnes and characterization of type I cell surface- associated antigens Andrew McDowell, 1 Anna Gao, 2,3 Emma Barnard, 1 Colin Fink, 3 Philip I. Murray, 4 Chris G. Dowson, 2 Istvan Nagy, 5 Peter A. Lambert 6 and Sheila Patrick 1 Correspondence Andrew McDowell a.mcdowell@qub.ac.uk Received 14 March 2011 Revised 14 April 2011 Accepted 15 April 2011 1 Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen’s University, 97 Lisburn Road, Belfast BT9 7BL, UK 2 School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK 3 Micropathology Ltd, University of Warwick Science Park, Coventry CV4 7EZ, UK 4 Academic Unit of Ophthalmology, School of Immunity and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham B18 7QU, UK 5 Institute for Plant Genomics, Human Biotechnology and Bioenergy, Bay Zoltan Foundation for Applied Research, H-6701, Hungary 6 School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK We have developed a novel multilocus sequence typing (MLST) scheme and database (http://pubmlst. org/pacnes/) for Propionibacterium acnes based on the analysis of seven core housekeeping genes. The scheme, which was validated against previously described antibody, single locus and random amplification of polymorphic DNA typing methods, displayed excellent resolution and differentiated 123 isolates into 37 sequence types (STs). An overall clonal population structure was detected with six eBURST groups representing the major clades I, II and III, along with two singletons. Two highly successful and global clonal lineages, ST6 (type IA) and ST10 (type IB 1 ), representing 64 % of this current MLST isolate collection were identified. The ST6 clone and closely related single locus variants, which comprise a large clonal complex CC6, dominated isolates from patients with acne, and were also significantly associated with ophthalmic infections. Our data therefore support an association between acne and P. acnes strains from the type IA cluster and highlight the role of a widely disseminated clonal genotype in this condition. Characterization of type I cell surface-associated antigens that are not detected in ST10 or strains of type II and III identified two dermatan-sulphate-binding proteins with putative phase/antigenic variation signatures. We propose that the expression of these proteins by type IA organisms contributes to their role in the pathophysiology of acne and helps explain the recurrent nature of the disease. The MLST scheme and database described in this study should provide a valuable platform for future epidemiological and evolutionary studies of P. acnes. INTRODUCTION Propionibacterium acnes is a Gram-positive aerotolerant anaerobic bacterium which forms part of the normal resident human microbiota of the skin, oral cavity, and gastrointestinal and genito-urinary tracts (Patrick & McDowell, 2011). The organism is an opportunistic pathogen most widely known for its association with acne vulgaris (Dessinioti & Katsambas, 2010) but it also causes bacterial keratitis (Ovodenko et al., 2009) and endophthal- mitis after ophthalmic surgery (Javey et al., 2010), and is increasingly recognized as a significant cause of medical Abbreviations: HMP, human microbiome project; IFM, immunofluores- cence microscopy; ME, minimum-evolution; ML, maximum-likelihood; MP, maximum-parsimony; MLST, multilocus sequence typing; RAPD, random amplification polymorphic DNA; SLV, single locus variant; SNP, single nucleotide polymorphism; ST, sequence type. The GenBank/EMBL/DDBJ accession numbers generated during this study are HQ283896–HQ283931 (sodA), HQ908360–HQ908395 (atpD), HQ908396–HQ908419 (recA), JF789639–JF789651 (aroE), JF789652–JF789658 (lepA), JF789659–JF789664 (gmk) and JF789665–JF789677 (guaA). Six supplementary figures and two supplementary tables are available with the online version of this paper. Microbiology (2011), 157, 1990–2003 DOI 10.1099/mic.0.049676-0 1990 049676 G 2011 SGM Printed in Great Britain