Evolution of mobile genetic element composition in an epidemic methicillin-resistant Staphylococcus aureus: temporal changes correlated with frequent loss and gain events

BMC Genomics

Research Article

Alasdair MacGowan¹  Tony Elston²  Ewan M. Harrison³  M. Estée Török⁴  Alison E. Mather⁵  Francesc Coll⁶  Andreas Karas⁷  Simon R. Harris⁸  Julian Parkhill⁸  Dorota Jamrozy⁸  Sharon J. Peacock⁹ 

[1] British Society for Antimicrobial Chemotherapy, B1 3NJ, Birmingham, UK;Colchester Hospital University NHS Foundation Trust, CO4 5JL, Colchester, UK;Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, CB2 0QQ, Cambridge, UK;Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, CB2 0QQ, Cambridge, UK;Public Health England, Clinical Microbiology and Public Health Laboratory, CB21 5XA, Cambridge, UK;Cambridge University Hospitals NHS Foundation Trust, CB2 0QQ, Cambridge, UK;Department of Veterinary Medicine, University of Cambridge, CB3 0ES, Cambridge, UK;London School of Hygiene and Tropical Medicine, WC1E 7HT, London, UK;Public Health England, Clinical Microbiology and Public Health Laboratory, CB21 5XA, Cambridge, UK;The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, CB10 1SA, Cambridge, UK;The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, CB10 1SA, Cambridge, UK;London School of Hygiene and Tropical Medicine, WC1E 7HT, London, UK;Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, CB2 0QQ, Cambridge, UK;Cambridge University Hospitals NHS Foundation Trust, CB2 0QQ, Cambridge, UK;

关键词: Staphylococcus aureus;    HA-MRSA;    EMRSA-15;    CC22;    Evolution;    MGE;    Horizontal gene transfer;   

DOI  :  10.1186/s12864-017-4065-z

 received in 2017-05-11, accepted in 2017-08-15,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundHorizontal 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.ResultsWe 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.ConclusionsAncestral 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.

【 授权许可】

CC BY   
© The Author(s). 2017