Genomic identification of cryptic susceptibility to penicillins and β-lactamase inhibitors in methicillin-resistant Staphylococcus aureus

Research output: Contribution to journalArticle

Authors

  • Ewan M. Harrison
  • Xiaoliang Ba
  • Francesc Coll
  • Beth Blane
  • Olivier Restif
  • Henry Carvell
  • Claudio U. Köser
  • Dorota Jamrozy
  • Sandra Reuter
  • Nicholas Gleadall
  • Katherine L. Bellis
  • Anne-Catrin Uhlemann
  • Franklin D. Lowy
  • Ruth C. Massey
  • Inês R. Grilo
  • Rita Sobral
  • Jesper Larsen
  • Anders Rhod Larsen
  • Carina Vingsbo Lundberg
  • Julian Parkhill
  • Gavin K Paterson
  • Matthew T. G. Holden
  • Sharon J Peacock
  • Mark A. Holmes

Colleges, School and Institutes

Abstract

Antibiotic resistance in bacterial pathogens threatens the future of modern medicine. One such resistant pathogen is methicillin-resistant Staphylococcus aureus (MRSA), which is resistant to nearly all β-lactam antibiotics, limiting treatment options. Here, we show that a significant proportion of MRSA isolates from different lineages, including the epidemic USA300 lineage, are susceptible to penicillins when used in combination with β-lactamase inhibitors such as clavulanic acid. Susceptibility is mediated by a combination of two different mutations in the mecA promoter region that lowers mecA-encoded penicillin-binding protein 2a (PBP2a) expression, and in the majority of isolates by either one of two substitutions in PBP2a (E246G or M122I) that increase the affinity of PBP2a for penicillin in the presence of clavulanic acid. Treatment of S. aureus infections in wax moth and mouse models shows that penicillin/β-lactamase inhibitor susceptibility can be exploited as an effective therapeutic choice for ‘susceptible’ MRSA infection. Finally, we show that isolates with the PBP2a E246G substitution have a growth advantage in the presence of penicillin but the absence of clavulanic acid, which suggests that penicillin/β-lactamase susceptibility is an example of collateral sensitivity (resistance to one antibiotic increases sensitivity to another). Our findings suggest that widely available and currently disregarded antibiotics could be effective in a significant proportion of MRSA infections.

Details

Original languageEnglish
Pages (from-to)1680-1691
Number of pages12
JournalNature Microbiology
Volume4
Issue number10
Early online date24 Jun 2019
Publication statusPublished - 1 Oct 2019