Antibiotic resistance has become a major challenge to public health worldwide. This crisis is further aggravated by the increasing emergence of bacterial resistance to carbapenems, typically considered as the antibiotics of last resort, which is mainly due to the production of carbapenem-hydrolyzing carbapenemases in bacteria. Herein, the carbapenem-based fluorogenic probe CB-1 with an unprecedented enamine-BODIPY switch is developed for the detection of carbapenemase activity. This reagent is remarkably specific towards carbapenemases over other prevalent β-lactamases. Furthermore, the efficient imaging of live clinically important carbapenemase-producing organisms (CPOs) with CB-1 demonstrates its potential for the rapid detection of antibiotic resistance and timely diagnosis of CPO infections.
The spread of antibiotic resistance in pathogenic bacteria has become one of the major concerns to public health. Improved monitoring of drug resistance is of high importance for infectious disease control. One of the major mechanisms for bacteria to overcome treatment of antibiotics is the production of β-lactamases, which are enzymes that hydrolyze the β-lactam ring of the antibiotic. In this study, we have developed a self-immobilizing and fluorogenic probe for the detection of β-lactamase activity. This fluorogenic reagent, upon activation by β-lactamases, turns on a fluorescence signal and, more importantly, generates a covalent linkage to the target enzymes or the nearby proteins. The covalent labeling of enzymes was confirmed by SDS-PAGE analysis and MALDI-TOF mass spectrometry. The utility of this structurally simple probe was further confirmed by the fluorescent labeling of a range of β-lactamase-expressing bacteria.
Metallo-β-lactamase is one of the major clinical threats because this β-lactam-hydrolyzing enzyme confers significant resistance to most β-lactam antibiotics, including carbapenems, among bacterial pathogens. Reported herein is a novel fluorogenic sensor for the specific detection of metallo-β-lactamase activities. This carbapenem-based reagent exhibits excellent selectivity to metallo-β-lactamase over other serine-β-lactamases, including serine carbapenemases. The usefulness of this probe was further demonstrated in the rapid identification of metallo-β-lactamase-expressing pathogenic bacteria.
Herein, a novel single-enzyme-assisted
dual recycle amplification
strategy based on T7 exonuclease (T7 Exo) and a strand-displacement
reaction (SDR) was designed to fabricate a photoelectrochemical (PEC)
biosensor for sensitive microRNA-141 (miRNA-141) detection with the
use of laminar bismuth tungstate (Bi2WO6) as
photoactive material. Compared with a traditional enzyme-assisted
dual recycle amplification strategy, the presented method could effectively
refrain the enzyme interference reaction, reduce environmental sensitivity,
and save cost. Here, hairpin DNA1 (H1) decorated on magnetic beads
(MB) hybridized with target miRNA-141 to form an H1/miRNA-141 heteroduplex.
With the introduction of hairpin DNA2 (H2)-labeled SiO2 (H2-SiO2), SDR was triggered between H2-SiO2 and H1, thus miRNA-141 was displaced from the H1/miRNA-141 heteroduplex
and an H1/H2-SiO2 duplex was formed, realizing the reuse
of the target. In the presence of T7 Exo, the H1/H2-SiO2 duplex was digested with the release of output DNA-SiO2. To enhance the target conversion rate, H1-MB was intactly released
and cycled, which could initiate more T7 Exo digestion and free abundant
output DNA-SiO2. Through such a process, a tiny miRNA-141
could induce substantial output DNA-SiO2, effectively improving
the target amplification efficiency and detection sensitivity of a
PEC biosensor. Furthermore, Bi2WO6 was modified
on an electrode to provide a superior initial PEC signal due to its
excellent electronic transformation capacity. With the introduction
of output DNA-SiO2, the hairpin structure of H3 on the
electrode was opened, making SiO2 close to the electrode
surface, which significantly decreases the PEC signal. This work first
established the PEC biosensor featuring a single-enzyme-assisted dual
recycle amplification process for sensitive detection of biomarkers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.