Subcellular Chemical Imaging of Antibiotics in Single Bacteria Using C60-Secondary Ion Mass Spectrometry.
The inherent difficulty of discovering new and effective antibacterials and the rapid development of resistance particularly in Gram-negative bacteria, illustrates the urgent need for new methods that enable rational drug design. Here we report the development of 3D imaging cluster Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) as a label-free approach to chemically map small molecules in aggregated and single Escherichia coli cells, with ∼300 nm spatial resolution and high chemical sensitivity. The feasibility of quantitative analysis was explored, and a nonlinear relationship between treatment dose and signal for tetracycline and ampicillin, two clinically used antibacterials, was observed. The methodology was further validated by the observation of reduction in tetracycline accumulation in an E. coli strain expressing the tetracycline-specific efflux pump (TetA) compared to the isogenic control. This study serves as a proof-of-concept for a new strategy for chemical imaging at the nanoscale and has the potential to aid discovery of new antibacterials.
Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
Hua
0000-0002-3598-0219
H
Tian
Novartis Institutes for BioMedical Research, Inc., 5300 Chiron Way, Emeryville, California 94608-2916, United States.
David A
DA
Six
Novartis Institutes for BioMedical Research, Inc., 5300 Chiron Way, Emeryville, California 94608-2916, United States.
Thomas
T
Krucker
Novartis Institutes for BioMedical Research, Inc., 5300 Chiron Way, Emeryville, California 94608-2916, United States.
Jennifer A
0000-0003-2244-4713
JA
Leeds
Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
Nicholas
N
Winograd
D000667:Ampicillin / Q000032:analysis / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000737:chemistry*; D057230:Limit of Detection; D059010:Single-Cell Analysis / Q000379:methods*; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods; D013752:Tetracycline / Q000032:analysis / Q000378:metabolism
D000900:Anti-Bacterial Agents; D000667:Ampicillin; D013752:Tetracycline