title: Assessment of inhibitory potency of antibiotics by MRI: apparent T2 as a marker of cell growth.
abstract: A new method to assess the antibiotic potency by MRI has been developed. Correlating 1H NMR spectra of bacterial cultures with the extracellular parameters T2, OD600, and pH, a relationship between cell growth and T2 variations was established. T2 is influenced by chemical exchange that depends on pH, composition, and concentration of the medium. Changes in the medium from bacterial metabolism are reflected in alternating T2 values. At 17.6 T, growth curves based on T2 values were measured simultaneously of several cultures of Streptococcus vestibularis. From T2 growth curves in the presence of varying concentrations of vancomycin, the minimum inhibitory concentration of the antibiotic could be determined to be 0.33+/-0.08 microM. This value was in good agreement with the result obtained by the conventional broth microdilution. In principle, T2 growth curves can be determined on a large number of cultures simultaneously and may potentially be used as a novel tool in high through-put screening of novel anti-infective substances.
authors.affiliation: Institute of Pharmacy and Food Chemistry, University of Würzburg, Würzburg, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Hoerr
authors.forename: Kerstin
authors.initials: K
authors.lastname: Hoffmann
authors.forename: Curd
authors.initials: C
authors.lastname: Schollmayer
authors.forename: Ulrike
authors.initials: U
authors.lastname: Holzgrabe
authors.forename: Axel
authors.initials: A
authors.lastname: Haase
authors.forename: Peter
authors.initials: P
authors.lastname: Jakob
authors.forename: Cornelius
authors.initials: C
authors.lastname: Faber
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D000890:Anti-Infective Agents / Q000494:pharmacology; D049109:Cell Proliferation; D004353:Drug Evaluation, Preclinical / Q000295:instrumentation* / Q000379:methods; D016903:Drug Monitoring / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008826:Microbial Sensitivity Tests / Q000295:instrumentation* / Q000379:methods; D008956:Models, Chemical; D015233:Models, Statistical; D013291:Streptococcus / Q000378:metabolism; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents