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Principal Investigator: Sophie Helaine
Organization: HARVARD MEDICAL SCHOOL
Fiscal Year: 2024
Award: $211,875
Funding agency: National Institute of Allergy and Infectious Diseases
PROJECT SUMMARY
Beside the well‐researched antibiotic resistance, bacterial pathogens can survive antibiotic exposure through
drug persistence. Persistence has been more difficult to study because of the transiency of the phenomenon,
where some bacteria arrest growth, thus surviving several antibiotics. Resumption of growth by persister is
thought to account for infection relapses but this has never been directly tested or demonstrated. With this
proposal, we aim at answering the fundamental question: are persisters the future “relapsors” and thereby
constitute a real reservoir for relapse of infections? In this project, we will make use of a remarkably useful model
intracellular pathogen, Salmonella enterica serovar Typhimurium to establish whether Salmonella persisters are
directly responsible for infection relapse. This proposal leverages further the development by our lab of model
systems and tools to track persisters in the context of infection. First, in Aim 1 of this project, we will adapt a
CRISPR‐based recorder that we recently built in the lab to record in the bacterial genome of persisters the state
of growth‐arrest, thus leaving an indelible genetic scar in CRISPR arrays that is perpetuated and detectable in
their progeny. We will further characterize this tool during infection of primary murine macrophages to
determine if, in addition to recording growth arrest, it can also be used as recorder of length of growth arrest.
We will also adapt pSCRATCH to record other signals in addition to growth arrest. Then, in Aim 2, we will use
the growth‐arrest recorder to assess for Salmonella, for the first time, whether persisters are the direct reservoir
for bacterial regrowth during relapse. This Aim will enable us to determine where relapsors originate from, from
growth‐arrested persisters or few growers not eradicated by the drugs for other reasons, such as lack of antibiotic
accessibility. It is of the utmost importance to determine whether persisters are the major source of infecting
bacteria during relapse in order to efficiently target persistent infections with improved therapeutics and
counteract the generation of antibiotic resistance.
Terms: <Antibiotic Agents><Antibiotic Drugs><Antibiotic Resistance><Antibiotic Therapy><Antibiotic Treatment><Antibiotics><Bacteria><Bacterial Genome><Biologic Models><Biological Models><Bone Marrow><Bone Marrow Reticuloendothelial System><CRISPR><CRISPR/Cas system><Cell Body><Cell Communication and Signaling><Cell Signaling><Cells><Cicatrix><Clustered Regularly Interspaced Short Palindromic Repeats><Development><Drug resistance><Drugs><Fluorescence><Future><Generalized Growth><Generations><Genes><Genetic><Genetic Alteration><Genetic Change><Genetic Markers><Genetic defect><Genome><Genotype><Goals><Growth><Health><Human><Infection><Intracellular Communication and Signaling><Laboratories><Length><M tb><M tuberculosis><M. tb><M. tuberculosis><Macrophage><Medication><Mice><Mice Mammals><Miscellaneous Antibiotic><Model System><Modeling><Modern Man><Murine><Mus><Mutation><Mycobacterium tuberculosis><Mφ><Organ><Pathogenicity><Pharmaceutical Preparations><Phenotype><Physiology><Public Health><Records><Regimen><Relapse><Reporting><Research><Resistance><Resistance to antibiotics><Resistant to antibiotics><Role><Route><S enterica><S enterica serovar Typhimurium><S typhimurium><S. enterica><S. enterica Typhimurium><S. enterica serovar Typhimurium><S. typhimurium><Salmonella><Salmonella enterica><Salmonella enterica Typhimurium><Salmonella enterica serovar Typhimurium><Salmonella infections><Salmonella typhimurium><Salmonellosis><Scars><Signal Transduction><Signal Transduction Systems><Signaling><Source><Stress><Symptoms><Testing><Therapeutic><Time><Tissue Growth><Treatment Failure><Variant><Variation><acute infection><antibiotic drug resistance><antibiotic resistant><bacteria pathogen><bacterial disease treatment><bacterial infectious disease treatment><bacterial pathogen><bacterial persister><biological signal transduction><chronic infection><design><designing><developmental><drug resistant><drug/agent><gene biomarker><gene expression biomarker><gene marker><gene signature biomarker><genetic biomarker><genome mutation><improved><microbial><mtb><ontogeny><pathogen><pathogenic bacteria><persistent bacteria><persistent infection><prevent><preventing><resistance to Drug><resistant><resistant to Drug><social role><stem><therapy failure><tool>