Department of Chemistry, University of Helsinki, Helsinki, Finland.
Folkhälsan Institute of Genetics, Folkhälsan Research Center, Biomedicum Helsinki, Helsinki, Finland.
Sci Rep. 2021 Aug 19;11(1):16897. doi: 10.1038/s41598-021-96287-7.
We have measured the volatile fingerprints of four pathogenic oral bacteria connected to periodontal disease and dental abscess: Porphyromonas gingivalis (three separate strains), Prevotella intermedia, Prevotella nigrescens and Tannerella forsythia. Volatile fingerprints were measured in vitro from the headspace gas of the bacteria cultured on agar. Concrete identification of new and previously reported bacterial volatiles were performed by a combination of solid phase microextraction (SPME) and offline gas chromatography-mass spectrometry (GC-MS). We also studied the effect of the reduced electric field strength (E/N) on the fragmentation patterns of bacterial volatiles in online proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS). We aimed to discover possible new biomarkers for the studied oral bacteria, as well as to validate the combination of GC-MS and PTR-MS for volatile analysis. Some of the most promising compounds produced include: 1-Methyl-1,2,3,4-tetrahydroisoquinoline (1MeTIQ), indole, and a cascade of sulphur compounds, such as methanethiol, dimethyl disulphide (DMDS) and dimethyl trisulphide (DMTS). We also found that several compounds, especially alcohols, aldehydes and esters, fragment significantly with the PTR-MS method, when high E/N values are used. We conclude that the studied oral bacteria can be separated by their volatile fingerprints in vitro, which could have importance in clinical and laboratory environments. In addition, using softer ionization conditions can improve the performance of the PTR-MS method in the volatile analysis of certain compounds.
我们已经测量了与牙周病和齿槽脓肿有关的四种病原性口腔细菌（牙龈卟啉单胞菌、中间普氏菌、黑色普氏菌和福赛坦纳氏菌）的挥发性指纹图谱。通过琼脂培养的细菌顶空气体中的固相微萃取（SPME）和离线气相色谱-质谱联用（GC-MS），对新的和以前报道的细菌挥发性物质进行了具体鉴定。我们还研究了降低电场强度（E/N）对在线质子转移反应飞行时间质谱（PTR-ToF-MS）中细菌挥发性物质碎片模式的影响。我们旨在发现所研究的口腔细菌的可能新生物标志物，并验证 GC-MS 和 PTR-MS 组合用于挥发性分析。产生的一些最有希望的化合物包括：1-甲基-1,2,3,4-四氢异喹啉（1MeTIQ）、吲哚和一系列硫化合物，如甲硫醇、二甲基二硫（DMDS）和二甲基三硫（DMTS）。我们还发现，当使用高 E/N 值时，几种化合物，特别是醇、醛和酯，用 PTR-MS 方法显著片段化。我们得出的结论是，研究中的口腔细菌可以通过其体外挥发性指纹图谱来分离，这在临床和实验室环境中可能具有重要意义。此外，使用更软的电离条件可以提高 PTR-MS 方法在某些化合物的挥发性分析中的性能。
