title: Antimicrobial susceptibility testing of Gram-positive and -negative bacterial isolates directly from spiked blood culture media with Raman spectroscopy.
abstract: Patients suffering from bacterial bloodstream infections have an increased risk of developing systematic inflammatory response syndrome (SIRS), which can result in rapid deterioration of the patients' health. Diagnostic methods for bacterial identification and antimicrobial susceptibility tests are time-consuming. The aim of this study was to investigate whether Raman spectroscopy would be able to rapidly provide an antimicrobial susceptibility profile from bacteria isolated directly from positive blood cultures. First, bacterial strains (n = 133) were inoculated in tryptic soy broth and incubated in the presence or absence of antibiotics for 5 h. Antimicrobial susceptibility profiles were analyzed by Raman spectroscopy. Subsequently, a selection of strains was isolated from blood cultures and analyzed similarly. VITEK®2 technology and broth dilution were used as the reference methods. Raman spectra from 67 antibiotic-susceptible strains showed discriminatory spectra in the absence or at low concentrations of antibiotics as compared to high antibiotic concentrations. For 66 antibiotic-resistant strains, no antimicrobial effect was observed on the bacterial Raman spectra. Full concordance with VITEK®2 data and broth dilution was obtained for the antibiotic-susceptible strains, 68 % and 98 %, respectively, for the resistant strains. Discriminative antimicrobial susceptibility testing (AST) profiles were obtained for all bacterial strains isolated from blood cultures, resulting in full concordance with the VITEK®2 data. It can be concluded that Raman spectroscopy is able to detect the antimicrobial susceptibility of bacterial species isolated from a positive blood culture bottle within 5 h. Although Raman spectroscopy is cheap and rapid, further optimization is required, to fulfill a great promise for future AST profiling technology development.
authors.affiliation: Research Department of Innovative Molecular Diagnostics, University of Applied Sciences Leiden, J. H. Oortweg 21, 2333 CH, Leiden, The Netherlands.
authors.forename: H E
authors.initials: HE
authors.lastname: Dekter
authors.affiliation: Research Department of Innovative Molecular Diagnostics, University of Applied Sciences Leiden, J. H. Oortweg 21, 2333 CH, Leiden, The Netherlands.
authors.forename: C C
authors.initials: CC
authors.lastname: Orelio
authors.affiliation: Research Department of Innovative Molecular Diagnostics, University of Applied Sciences Leiden, J. H. Oortweg 21, 2333 CH, Leiden, The Netherlands.
authors.forename: M C
authors.initials: MC
authors.lastname: Morsink
authors.affiliation: Research Department of Innovative Molecular Diagnostics, University of Applied Sciences Leiden, J. H. Oortweg 21, 2333 CH, Leiden, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Tektas
authors.affiliation: Research Department of Innovative Molecular Diagnostics, University of Applied Sciences Leiden, J. H. Oortweg 21, 2333 CH, Leiden, The Netherlands.
authors.forename: B
authors.initials: B
authors.lastname: Vis
authors.affiliation: Netherlands Molecular Diagnostic Laboratory B.V. (NMDL), Visseringlaan 25, 2288 ER, Rijswijk, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Te Witt
authors.affiliation: Research Department of Innovative Molecular Diagnostics, University of Applied Sciences Leiden, J. H. Oortweg 21, 2333 CH, Leiden, The Netherlands. leeuwen.van.w@hsleiden.nl.
authors.forename: W B
authors.initials: WB
authors.lastname: van Leeuwen
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000382:microbiology; D001419:Bacteria / Q000737:chemistry* / Q000187:drug effects*; D000071997:Blood Culture / Q000379:methods*; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents