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Jamrozy D, Coll F, Mather AE, Harris SR, Harrison EM, MacGowan A, Karas A, Elston T, Estée Török M, Parkhill J, Peacock SJ. Evolution of mobile genetic element composition in an epidemic methicillin-resistant Staphylococcus aureus: temporal changes correlated with frequent loss and gain events. BMC Genomics 2017; 18:684. [PMID: 28870171 PMCID: PMC5584012 DOI: 10.1186/s12864-017-4065-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 08/15/2017] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Horizontal transfer of mobile genetic elements (MGEs) that carry virulence and antimicrobial resistance genes mediates the evolution of methicillin-resistant Staphylococcus aureus, and the emergence of new MRSA clones. Most MRSA lineages show an association with specific MGEs and the evolution of MGE composition following clonal expansion has not been widely studied. RESULTS We investigated the genomes of 1193 S. aureus bloodstream isolates, 1169 of which were MRSA, collected in the UK and the Republic of Ireland between 2001 and 2010. The majority of isolates belonged to clonal complex (CC)22 (n = 923), which contained diverse MGEs including elements that were found in other MRSA lineages. Several MGEs showed variable distribution across the CC22 phylogeny, including two antimicrobial resistance plasmids (pWBG751-like and SAP078A-like, carrying erythromycin and heavy metal resistance genes, respectively), a pathogenicity island carrying the enterotoxin C gene and two phage types Sa1int and Sa6int. Multiple gains and losses of these five MGEs were identified in the CC22 phylogeny using ancestral state reconstruction. Analysis of the temporal distribution of the five MGEs between 2001 and 2010 revealed an unexpected reduction in prevalence of the two plasmids and the pathogenicity island, and an increase in the two phage types. This occurred across the lineage and was not correlated with changes in the relative prevalence of CC22, or of any sub-lineages within in. CONCLUSIONS Ancestral state reconstruction coupled with temporal trend analysis demonstrated that epidemic MRSA CC22 has an evolving MGE composition, and indicates that this important MRSA lineage has continued to adapt to changing selective pressure since its emergence.
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Affiliation(s)
- Dorota Jamrozy
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA UK
| | - Francesc Coll
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK
| | - Alison E. Mather
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES UK
| | - Simon R. Harris
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA UK
| | - Ewan M. Harrison
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, CB2 0QQ UK
| | - Alasdair MacGowan
- British Society for Antimicrobial Chemotherapy, B1 3NJ, Birmingham, UK
| | - Andreas Karas
- Public Health England, Clinical Microbiology and Public Health Laboratory, Cambridge, CB21 5XA UK
| | - Tony Elston
- Colchester Hospital University NHS Foundation Trust, Colchester, CO4 5JL UK
| | - M. Estée Török
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, CB2 0QQ UK
- Public Health England, Clinical Microbiology and Public Health Laboratory, Cambridge, CB21 5XA UK
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, CB2 0QQ UK
| | - Julian Parkhill
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA UK
| | - Sharon J. Peacock
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA UK
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, CB2 0QQ UK
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, CB2 0QQ UK
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