MXene-coated paper microextraction patch for in vitro metabolic profiling to identify Klebsiella pneumoniae

Klebsiella pneumoniae poses a significant threat to immunocompromised patients due to its high prevalence in hospital-acquired respiratory infections. The identification of bacterial species is crucial for transitioning from broad-spectrum to narrow-spectrum antibiotics in cases of antibiotic resistance. Here, an MXene/Ti₃C₂T_x/divinylbenzene-coated paper strip was developed for profiling of K. pneumoniae-associated (ATCC 13883) metabolites during in vitro growth media of the pathogen. The regular cellular paper was coated with a MXene/Ti₃C₂T_x composite using a film applicator, and the coated sheet was trimmed into several pieces to obtain multiple analytical tools. The patches were directly immersed in Lysogeny broth (LB) during the log phase of bacterial growth, and the bacterial metabolites were extracted by the microextraction device and finally determined by triple-quadrupole gas chromatography mass spectrometry. Fifty-seven metabolites, including alcohol, ketones, and hydrocarbons, were identified from the culture media of K. pneumoniae. To investigate the eco-friendliness of this technique, the Blue Applicability Grade Index (BAGI) was determined to be 72.5, suggesting the suitability of this method as a green sample preparation technique for implementation in pathology settings. Therefore, this study may offer an alternative and potentially effective approach for the rapid identification of the Klebsiella pneumoniae pathogen. As the metabolic profiling was performed during the growth phase of the bacterial species, this approach may directly reflect metabolites of actively growing cells from the sample matrix, whereas the conventional PCR-based technique is limited in distinguishing between dead and active bacterial species.