β-Lactamase Sensitive Probe for Rapid Detection of Antibiotic-Resistant Bacteria with Gas Chromatography-Tandem Mass Spectrometry.

β-Lactamase (Bla) produced by bacteria to resist β-lactam antibiotics is a serious public health threat. Developing efficient diagnostic protocols for drug-resistant bacteria is of great significance. In this work, based on gas molecules in bacteria, a novel research strategy was proposed to develop a gas molecule-based probe by grafting 2-methyl-3-mercaptofuran (MF) onto cephalosporin intermediates via a nucleophilic substitution reaction. The probe can release the corresponding MF by reacting with Bla. The released MF, as a marker of drug-resistant bacteria, was analyzed by headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry. The Bla concentration as low as 0.2 nM can be easily observed, providing an efficient method for detecting enzyme activity and screening drug-resistant strains in vivo. Importantly, the method is universal, and probes with different properties can be prepared by changing different substrates to further identify different types of bacteria, thereby broadening the research methods and ideas for monitoring physiological processes.