Evolution of Multidrug Resistance during Staphylococcus aureus Infection Involves Mutation of the Essential Two Component Regulator WalKR

PLoS Pathogens

Vicki Bennett-Wood¹  Christopher R. E. McEvoy¹  Jan Bell²  Timothy P. Stinear²  Benjamin P. Howden²  Wei Gao²  Geoffrey Coombs³  Paul F. Harrison³  Jessica L. Porter³  Kyra Chua³  David L. Allen⁴  Torsten Seemann⁵  John K. Davies⁶  Roy Robins-Browne⁷ 

[1] Austin Centre for Infection Research (ACIR), Infectious Diseases Department, Austin Health, Heidelberg, Victoria, Australia;Department of Microbiology and Immunology, University of Melbourne, Victoria, Australia;Department of Microbiology, Monash University, Clayton, Victoria, Australia;Microbiology Department, Austin Health, Heidelberg, Victoria, Australia;Microbiology Department, Royal Perth Hospital, Perth, Western Australia, Australia;SA Pathology, Womens and Children’s Hospital, Adelaide, South Australia, Australia;Victorian Bioinformatics Consortium, Monash University, Clayton, Victoria, Australia

关键词: Point mutation;    Mutant strains;    Staphylococcus aureus;    Vancomycin;    Cell walls;    Antimicrobial resistance;    Microarrays;    Mutation detection;   

DOI  :  10.1371/journal.ppat.1002359

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Antimicrobial resistance in Staphylococcus aureus is a major public health threat, compounded by emergence of strains with resistance to vancomycin and daptomycin, both last line antimicrobials. Here we have performed high throughput DNA sequencing and comparative genomics for five clinical pairs of vancomycin-susceptible (VSSA) and vancomycin-intermediate ST239 S.aureus (VISA); each pair isolated before and after vancomycin treatment failure. These comparisons revealed a frequent pattern of mutation among the VISA strains within the essential walKR two-component regulatory locus involved in control of cell wall metabolism. We then conducted bi-directional allelic exchange experiments in our clinical VSSA and VISA strains and showed that single nucleotide substitutions within either walK or walR lead to co-resistance to vancomycin and daptomycin, and caused the typical cell wall thickening observed in resistant clinical isolates. Ion Torrent genome sequencing confirmed no additional regulatory mutations had been introduced into either the walR or walK VISA mutants during the allelic exchange process. However, two potential compensatory mutations were detected within putative transport genes for the walK mutant. The minimal genetic changes in either walK or walR also attenuated virulence, reduced biofilm formation, and led to consistent transcriptional changes that suggest an important role for this regulator in control of central metabolism. This study highlights the dramatic impacts of single mutations that arise during persistent S.aureus infections and demonstrates the role played by walKR to increase drug resistance, control metabolism and alter the virulence potential of this pathogen.

【 授权许可】

CC BY