title: Rapid detection of antibiotic resistance based on mass spectrometry and stable isotopes.
abstract: With the emergence and growing complexity of bacterial drug resistance, rapid and reliable susceptibility testing has become a topical issue. Therefore, new technologies that assist in predicting the effectiveness of empiric antibiotic therapy are of great interest. Although the use of matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) for the rapid detection of antibiotic resistance is an attractive option, the current methods for MALDI-TOF MS susceptibility testing are restricted to very limited conditions. Here, we describe a technique that may allow for rapid susceptibility testing to an extent that is comparable to phenotypic methods. The test was based on a stable isotope labelling by amino acids in cell culture (SILAC)-like approach. This technique was used to visualise the growth of bacteria in the presence of an antibiotic. Pseudomonas aeruginosa was chosen as the model organism, and strains were incubated in normal medium, medium supplemented with (13)C6-(15) N2-labelled lysine and medium supplemented with labelled lysine and antibiotic. Peak shifts occurring due to the incorporation of the labelled amino acids were detected by MALDI-TOF MS. Three antibiotics with different mechanisms of action, meropenem, tobramycin and ciprofloxacin, were tested. A semi-automated algorithm was created to enable rapid and unbiased data evaluation. With the proposed test, a clear distinction between resistant and susceptible isolates was possible for all three antibiotics. The application of SILAC technology for the detection of antibiotic resistance may contribute to accelerated and reliable susceptibility testing.
authors: Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Marchioninistr. 17, 81377, Munich, Germany, jung@mvp.uni-muenchen.de.
authors: J S
authors: JS
authors: Jung
authors: T
authors: T
authors: Eberl
authors: K
authors: K
authors: Sparbier
authors: C
authors: C
authors: Lange
authors: M
authors: M
authors: Kostrzewa
authors: S
authors: S
authors: Schubert
authors: A
authors: A
authors: Wieser
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002939:Ciprofloxacin / Q000494:pharmacology; D003470:Culture Media / Q000737:chemistry; D024881:Drug Resistance, Bacterial; D007553:Isotope Labeling; D007554:Isotopes / Q000378:metabolism*; D013058:Mass Spectrometry / Q000379:methods*; D000077731:Meropenem; D008826:Microbial Sensitivity Tests / Q000379:methods; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D013845:Thienamycins / Q000494:pharmacology; D013997:Time Factors; D014031:Tobramycin / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D000900:Anti-Bacterial Agents; D003470:Culture Media; D007554:Isotopes; D013845:Thienamycins; D002939:Ciprofloxacin; D000077731:Meropenem; D014031:Tobramycin