Aminoglycoside‐Enabled Elucidation of Bacterial Persister Metabolism

Abstract

Bacterial persisters are cells with an impressive, yet transient, tolerance toward extraordinary concentrations of antibiotics. Persisters are believed to impose a significant burden on the healthcare system because of their role in the proclivity of infections to relapse. During antibiotic challenge, these rare, phenotypic variants enter a dormant state where antibiotic primary targets are rendered inactive, allowing them to survive. Once the antibiotic is removed, persisters reawaken and resume growth, leading to repopulation of the environment. Metabolism plays a pivotal role in coordinating the entry, maintenance, and exit from the persister state. However, the low abundance, transient nature, and similarity of persisters to other cell types have prevented their isolation, which is needed for direct metabolic measurements. In this unit, we describe a technique known as the aminoglycoside (AG) potentiation assay, which can be used to rapidly and specifically measure the breadth of persister metabolism in heterogeneous populations. © 2015 by John Wiley & Sons, Inc.

Promiscuous signaling by a regulatory system unique to the pandemic PMEN1 pneumococcal lineage

“…To identify the TprA2 regulon, we compared the gene expression levels of the wild-type (WT) PMEN1 strain PN4595-T23 and the isogenic tprA2 deletion mutant (Δ tprA2) , utilizing a pneumococcal gene array ( S5 Table ) [ 34 ]. The expression of the phrA2-ABC and lcpAMT genes were >30-fold higher in Δ tprA2 relative to the WT strain.…”

“…For experiments on in vitro transcriptional analysis, samples were collected for RNA extraction at an OD 600 of 0.5 unless otherwise stated and preparation of RNA was performed as previously described in [ 34 ]. For RNA extraction from in vivo experiments, chinchillas were euthanized 48h post-inoculation of PN4595-T23, and a small opening was generated through the bulla to access the middle ear cavity.…”

Antibacterial Activities of Aliphatic Polyester Nanocomposites with Silver Nanoparticles and/or Graphene Oxide Sheets

“…In the final stage of biofilm development, clusters of bacteria cells detach from the biofilm so that they spread and colonize new surfaces. Moreover, a small subpopulation of inactive or dormant variants of bacterial cells within the film, i.e., the ‘persister’, exhibits antibiotic tolerance and can turn active when the antimicrobial agent is removed [9]. Thus, implant-related infections are serious complications for patients because they can induce a severe inflammatory response in the surrounding tissues such as osteomyelitis, endocarditis, urinary tract infection, etc.…”

Non-Monotonic Survival of Staphylococcus aureus with Respect to Ciprofloxacin Concentration Arises from Prophage-Dependent Killing of Persisters

“…Persisters are enumerated from antibiotic-treated cultures that display biphasic killing kinetics, where the second regime, which exhibits a reduced rate of cell death, comprises persisters [ 12 , 13 , 28 , 29 ]. To perform these experiments, an antibiotic concentration high enough to kill any spontaneously-generated mutants must be used, and the duration of treatment to reach the second regime of killing must be identified.…”