1. Epistasis analysis uncovers hidden antibiotic resistance-associated fitness costs hampering the evolution of MRSA
- Author
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Maisem Laabei, Leann Bacon, Nicola Ooi, Mario Recker, Ruth C. Massey, Laurence D. Hurst, Emily Stevens, Guillaume Méric, Samuel K. Sheppard, Paul Williams, Ben Pascoe, Anneke Lubben, Alex J. O'Neill, Kate J. Heesom, Maho Yokoyama, Sion C. Bayliss, Ewan Murray, and Shaun Reeksting
- Subjects
0301 basic medicine ,Isoleucine-tRNA Ligase ,Methicillin-Resistant Staphylococcus aureus ,Proteomics ,lcsh:QH426-470 ,medicine.drug_class ,030106 microbiology ,Antibiotics ,Bacterial Toxins ,Epistasis and functional genomics ,Mupirocin ,MRSA ,Microbial Sensitivity Tests ,Biology ,Evolution, Molecular ,03 medical and health sciences ,chemistry.chemical_compound ,Antibiotic resistance ,Bacterial Proteins ,Drug Resistance, Bacterial ,medicine ,GWAS ,Mupirocin resistance ,lcsh:QH301-705.5 ,Genetics ,Mechanism (biology) ,Research ,Epistasis, Genetic ,Resistance mutation ,Anti-Bacterial Agents ,lcsh:Genetics ,Fitness costs ,030104 developmental biology ,chemistry ,lcsh:Biology (General) ,Genetic Loci ,Mutation ,Epistasis ,Genetic Fitness ,Functional genomics ,Genome, Bacterial - Abstract
Background Fitness costs imposed on bacteria by antibiotic resistance mechanisms are believed to hamper their dissemination. The scale of these costs is highly variable. Some, including resistance of Staphylococcus aureus to the clinically important antibiotic mupirocin, have been reported as being cost-free, which suggests that there are few barriers preventing their global spread. However, this is not supported by surveillance data in healthy communities, which indicate that this resistance mechanism is relatively unsuccessful. Results Epistasis analysis on two collections of MRSA provides an explanation for this discord, where the mupirocin resistance-conferring mutation of the ileS gene appears to affect the levels of toxins produced by S. aureus when combined with specific polymorphisms at other loci. Proteomic analysis demonstrates that the activity of the secretory apparatus of the PSM family of toxins is affected by mupirocin resistance. As an energetically costly activity, this reduction in toxicity masks the fitness costs associated with this resistance mutation, a cost that becomes apparent when toxin production becomes necessary. This hidden fitness cost provides a likely explanation for why this mupirocin-resistance mechanism is not more prevalent, given the widespread use of this antibiotic. Conclusions With dwindling pools of antibiotics available for use, information on the fitness consequences of the acquisition of resistance may need to be considered when designing antibiotic prescribing policies. However, this study suggests there are levels of depth that we do not understand, and that holistic, surveillance and functional genomics approaches are required to gain this crucial information. Electronic supplementary material The online version of this article (10.1186/s13059-018-1469-2) contains supplementary material, which is available to authorized users.
- Published
- 2018