Abstract

The past decade has seen an increase in the prevalence of sequence type (ST) 45 methicillin-resistant Staphylococcus aureus (MRSA), yet the underlying drivers for its emergence and spread remain unclear. To better understand the worldwide dissemination of ST45 S. aureus, we performed phylogenetic analyses of Australian isolates, supplemented with a global population of ST45 S. aureus genomes. Our analyses revealed a distinct lineage of multidrug-resistant ST45 MRSA harbouring qacA, predominantly found in Australia and Singapore. Bayesian inference predicted that the acquisition of qacA occurred in the late 1990s. qacA was integrated into a structurally variable region of the chromosome containing Tn552 (carrying blaZ) and Tn4001 (carrying aac(6’)-aph(2”)) transposable elements. Using mutagenesis and in vitro assays, we provide phenotypic evidence that qacA confers tolerance to chlorhexidine. These findings collectively suggest both antimicrobial resistance and the carriage of qacA may play a role in the successful establishment of ST45 MRSA.

A study underscores the emergence of a qacA-harbouring multidrug-resistant sequence type 45 methicillin-resistant Staphylococcus aureus lineage, highlighting the potential impact of biocide tolerance on its recent clonal spread in Australia and Asia.

Details

Title
Emergence and clonal expansion of a qacA-harbouring sequence type 45 lineage of methicillin-resistant Staphylococcus aureus
Author
Nong, Yi 1   VIAFID ORCID Logo  ; Steinig, Eike 2 ; Pollock, Georgina L. 2   VIAFID ORCID Logo  ; Taiaroa, George 2 ; Carter, Glen P. 3   VIAFID ORCID Logo  ; Monk, Ian R. 1   VIAFID ORCID Logo  ; Pang, Stanley 4   VIAFID ORCID Logo  ; Daley, Denise A. 5 ; Coombs, Geoffrey W. 4 ; Forde, Brian M. 6   VIAFID ORCID Logo  ; Harris, Patrick N. A. 7   VIAFID ORCID Logo  ; Sherry, Norelle L. 8   VIAFID ORCID Logo  ; Howden, Benjamin P. 8   VIAFID ORCID Logo  ; Pasricha, Shivani 2 ; Baines, Sarah L. 1   VIAFID ORCID Logo  ; Williamson, Deborah A. 9   VIAFID ORCID Logo 

1  The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, Melbourne, Australia (GRID:grid.1008.9) (ISNI:0000 0001 2179 088X) 
2  The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Department of Infectious Diseases, Melbourne, Australia (GRID:grid.1008.9) (ISNI:0000 0001 2179 088X) 
3  The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, Melbourne, Australia (GRID:grid.1008.9) (ISNI:0000 0001 2179 088X); The University of Melbourne, Doherty Applied Microbial Genomics, Doherty Institute, Melbourne, Australia (GRID:grid.1008.9) (ISNI:0000 0001 2179 088X) 
4  Murdoch University, Antimicrobial Resistance and Infectious Diseases Research Laboratory, Murdoch, Australia (GRID:grid.1025.6) (ISNI:0000 0004 0436 6763); PathWest Laboratory Medicine-WA, Fiona Stanley Hospital, Department of Microbiology, Murdoch, Australia (GRID:grid.1025.6) 
5  Fiona Stanley Hospital, Australian Group on Antimicrobial Resistance, Murdoch, Australia (GRID:grid.459958.c) (ISNI:0000 0004 4680 1997) 
6  UQ Centre for Clinical Research, The University of Queensland, Faculty of Medicine, Brisbane, Australia (GRID:grid.1003.2) (ISNI:0000 0000 9320 7537) 
7  UQ Centre for Clinical Research, The University of Queensland, Faculty of Medicine, Brisbane, Australia (GRID:grid.1003.2) (ISNI:0000 0000 9320 7537); Royal Brisbane and Women’s Hospital, Central Microbiology, Pathology Queensland, Brisbane, Australia (GRID:grid.416100.2) (ISNI:0000 0001 0688 4634) 
8  The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Department of Microbiology and Immunology, Melbourne, Australia (GRID:grid.1008.9) (ISNI:0000 0001 2179 088X); The University of Melbourne at The Doherty Institute for Infection and Immunity, Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology & Immunology, Melbourne, Australia (GRID:grid.1008.9) (ISNI:0000 0001 2179 088X) 
9  The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Department of Infectious Diseases, Melbourne, Australia (GRID:grid.1008.9) (ISNI:0000 0001 2179 088X); Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Victorian Infectious Diseases Reference Laboratory, Melbourne, Australia (GRID:grid.416153.4) (ISNI:0000 0004 0624 1200) 
Pages
349
Publication year
2024
Publication date
2024
Publisher
Nature Publishing Group
e-ISSN
23993642
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1038/s42003-024-06012-z
ProQuest document ID
2972994826
Copyright
© The Author(s) 2024. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.