title: Fluorescence spectroscopy: a rapid tool for assessing tetracycline resistance in Bifidobacterium longum.
abstract: The tetracycline uptake kinetics of 35 Bifidobacterium longum strains isolated from the human gastrointestinal tract were examined by fluorescence spectroscopy, and the suitability of the technique as a screening tool of tetracycline resistance or susceptibility was determined. The strains were first grouped into three classes based on their corresponding minimum inhibitory concentrations (MICs) of tetracycline, as established by the microdilution method: susceptible (MICs <or=1 microg mL(-1)), semi-resistant (MICs between 1 and <or=32 microg mL(-1), and resistant strains (MICs >or=32 microg mL(-1)). The kinetics of tetracycline uptake for the strains in each resistance group were then analyzed over a 20 min period by fluorescence spectroscopy (absorbance wavelength 524 nm, excitation wavelength 400 nm) in a buffer system containing 100 microg mL(-1) tetracycline. Principal component analysis and factorial discriminant analysis of the results showed excellent distinction among susceptible, semi-resistant, and resistant strains. The proposed method provides a powerful and convenient means of rapidly screening tetracycline resistance in B. longum.
authors.affiliation: Institute de Productos Lácteos de Asturias, CSIC, Carretera de Infiesto s/n, 33300 Villaviciosa, Asturias, Spain. ammor@ipla.csic.es
authors.forename: Mohammed Salim
authors.initials: MS
authors.lastname: Ammor
authors.forename: Ana Belén
authors.initials: AB
authors.lastname: Flórez
authors.forename: Abelardo
authors.initials: A
authors.lastname: Margolles
authors.forename: Baltasar
authors.initials: B
authors.lastname: Mayo
mesh_terms: D001644:Bifidobacterium / Q000145:classification / Q000187:drug effects* / Q000302:isolation & purification / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000382:microbiology; D006801:Humans; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D008954:Models, Biological; D013045:Species Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013752:Tetracycline / Q000378:metabolism / Q000494:pharmacology; D013753:Tetracycline Resistance
chemical_list: D013752:Tetracycline