MALDI-TOF Mass Spectrometry-Based Optochin Susceptibility Testing for Differentiation of Streptococcus pneumoniae from other Streptococcus mitis Group Streptococci †
| Autor: | Karsten Becker, Andreas Schlattmann, Ilka D. Nix, Markus Kostrzewa, Evgeny A. Idelevich, Katrin Sparbier |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Microbiology (medical)
Susceptibility testing QH301-705.5 Mass spectrometry medicine.disease_cause Microbiology Article Incubation period Matrix (chemical analysis) chemistry.chemical_compound rapid test Virology Streptococcus mitis Streptococcus pneumoniae medicine Biology (General) Chromatography biology Chemistry Optochin DOT-MGA MALDI-TOF mass spectrometry optochin susceptibility testing MALDI-TOF Mass Spectrometry biology.organism_classification |
| Zdroj: | Microorganisms Microorganisms, Vol 9, Iss 2010, p 2010 (2021) Volume 9 Issue 10 |
| ISSN: | 2076-2607 |
| Popis: | Discrimination of Streptococcus pneumoniae from other Streptococcus mitis group (SMG) species is still challenging but very important due to their different pathogenic potential. In this study, we aimed to develop a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)-based optochin susceptibility test with an objective read-out. Optimal test performance was established and evaluated by testing consecutively collected respiratory isolates. Optochin in different concentrations as a potential breakpoint concentration was added to a standardized inoculum. Droplets of 6 µL with optochin and, as growth control, without optochin were spotted onto a MALDI target. Targets were incubated in a humidity chamber, followed by medium removal and on-target protein extraction with formic acid before adding matrix with an internal standard. Spectra were acquired, and results were interpreted as S. pneumoniae in the case of optochin susceptibility (no growth), or as non-S. pneumoniae in the case of optochin non-susceptibility (growth). Highest test accuracy was achieved after 20 h incubation time (95.7%). Rapid testing after 12 h incubation time (optochin breakpoint 2 µg/mL correct classification 100%, validity 62.5%) requires improvement by optimization of assay conditions. The feasibility of the MALDI-TOF MS-based optochin susceptibility test was demonstrated in this proof-of-principle study however, confirmation and further improvements are warranted. |
| Databáze: | OpenAIRE |
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