title: Bacterial drug tolerance under clinical conditions is governed by anaerobic adaptation but not anaerobic respiration.
abstract: Noninherited antibiotic resistance is a phenomenon whereby a subpopulation of genetically identical bacteria displays phenotypic tolerance to antibiotics. We show here that compared to Escherichia coli, the clinically relevant genus Burkholderia displays much higher levels of cells that tolerate ceftazidime. By measuring the dynamics of the formation of drug-tolerant cells under conditions that mimic in vivo infections, we show that in Burkholderia bacteria, oxygen levels affect the formation of these cells. The drug-tolerant cells are characterized by an anaerobic metabolic signature and can be eliminated by oxygenating the system or adding nitrate. The transcriptome profile suggests that these cells are not dormant persister cells and are likely to be drug tolerant as a consequence of the upregulation of anaerobic nitrate respiration, efflux pumps, β-lactamases, and stress response proteins. These findings have important implications for the treatment of chronic bacterial infections and the methodologies and conditions that are used to study drug-tolerant and persister cells in vitro.
authors: Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
authors: Claudia M
authors: CM
authors: Hemsley
authors: School of Life Sciences, University of Warwick, Coventry, United Kingdom.
authors: Jamie X
authors: JX
authors: Luo
authors: Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
authors: Clio A
authors: CA
authors: Andreae
authors: Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
authors: Clive S
authors: CS
authors: Butler
authors: School of Life Sciences, University of Warwick, Coventry, United Kingdom.
authors: Orkun S
authors: OS
authors: Soyer
authors: Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom r.w.titball@exeter.ac.uk.
authors: Richard W
authors: RW
authors: Titball
mesh_terms: D000693:Anaerobiosis; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D019117:Burkholderia / Q000187:drug effects* / Q000378:metabolism*; D002442:Ceftazidime / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D059467:Transcriptome / Q000187:drug effects / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D002442:Ceftazidime