A Structurally Characterized Staphylococcus aureus Evolutionary Escape Route from Treatment with the Antibiotic Linezolid

Laura Perlaza-Jiménez, Kher Shing Tan, Sarah J. Piper, Rachel M. Johnson, Rebecca S. Bamert, Christopher J. Stubenrauch, Alexander Wright, David Lupton, Trevor Lithgow, Matthew J. Belousoff

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2 Citations (Scopus)


Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterial pathogen that presents great health concerns. Treatment requires the use of last-line antibiotics, such as members of the oxazolidinone family, of which linezolid is the first member to see regular use in the clinic. Here, we report a short time scale selection experiment in which strains of MRSA were subjected to linezolid treatment. Clonal isolates which had evolved a linezolid-resistant phenotype were characterized by whole-genome sequencing. Linezolid-resistant mutants were identified which had accumulated mutations in the ribosomal protein uL3. Multiple clones which had two mutations in uL3 exhibited resistance to linezolid, 2-fold higher than the clinical breakpoint. Ribosomes from this strain were isolated and subjected to single-particle cryo-electron microscopic analysis and compared to the ribosomes from the parent strain. We found that the mutations in uL3 lead to a rearrangement of a loop that makes contact with Helix 90, propagating a structural change over 15 Å away. This distal change swings nucleotide U2504 into the binding site of the antibiotic, causing linezolid resistance. IMPORTANCE Antibiotic resistance poses a critical problem to human health and decreases the utility of these lifesaving drugs. Of particular concern is the "superbug" methicillin-resistant Staphylococcus aureus (MRSA), for which treatment of infection requires the use of last-line antibiotics, including linezolid. In this paper, we characterize the atomic rearrangements which the ribosome, the target of linezolid, undergoes during its evolutionary journey toward becoming drug resistant. Using cryo-electron microscopy, we describe a particular molecular mechanism which MRSA uses to become resistant to linezolid.

Original languageEnglish
Article numbere0058322
Number of pages11
JournalMicrobiology Spectrum
Issue number4
Publication statusPublished - Jul 2022


  • antibiotic resistance
  • antibiotics
  • antimicrobial resistance
  • cryoEM
  • drug resistance evolution
  • electron microscopy
  • linezolid
  • MRSA
  • ribosomes
  • Staphylococcus aureus

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