Modified Enzyme Substrates for the Detection of Bacteria: A Review

Abstract

The ability to detect, identify and quantify bacteria is crucial in clinical diagnostics, environmental testing, food security settings and in microbiology research. Recently, the threat of multidrug-resistant bacterial pathogens pushed the global scientific community to develop fast, reliable, specific and affordable methods to detect bacterial species. The use of synthetically modified enzyme substrates is a convenient approach to detect bacteria in a specific, economic and rapid manner. The method is based on the use of specific enzyme substrates for a given bacterial marker enzyme, conjugated to a signalogenic moiety. Following enzymatic reaction, the signalophor is released from the synthetic substrate, generating a specific and measurable signal. Several types of signalophors have been described and are defined by the type of signal they generate, such as chromogenic, fluorogenic, luminogenic, electrogenic and redox. Signalophors are further subdivided into groups based on their solubility in water, which is key in defining their application on solid or liquid media for bacterial culturing. This comprehensive review describes synthetic enzyme substrates and their applications for bacterial detection, showing their mechanism of action and their synthetic routes.

Advances in Optical Sensors of N-Acetyl-β-d-hexosaminidase (N-Acetyl-β-d-glucosaminidase)

“…From a molecular design perspective, the task is more complicated than a simple exchange of the optical reporter component within the substrate chemical structure. As summarized in recent reviews, optimization of colorimetric/fluorometric enzyme substrates is a multiparameter problem that has to produce a molecule with a proper combination of chemical, physical, spectral, and enzyme recognition properties. − In some cases, the probe optimization process can be achieved by an iterative cycle of rational design, but in other cases it may be more efficient to screen libraries of substrate candidates.…”

“…Over time, the technology has expanded in various directions, and colorimetric/fluorometric enzyme substrates are now incorporated into a variety of different methods for imaging and diagnostics. Several recent review articles have summarized the broad strategies used to create colorimetric/fluorometric enzyme substrates, − and the more specific topic of reactive probes for glycosidase enzymes . However, to the best of our knowledge this review article is the first to collate the different chromogenic and fluorogenic substrates for N -acetyl-β- d -hexosaminidases, a major subgroup of glycosyl hydrolase enzymes with increasing biomedical importance.…”

Emerging Bioanalytical Devices and Platforms for Rapid Detection of Pathogens in Environmental Samples

“…Enzymatic Method [65] (i) Simple, fast (1 h), no trained staff or advanced tools, required (ii) Highly selective and sensitive (iii) Screening tests could be conducted without even any cultivation steps (i) Enzymes are generally expensive and lose activity easily (ii) Any fluorescence signal enhancement techniques require prior growth of the target microbes (iii) Compatibility issue…”

The Evaluation of Ester Functionalised TCF‐Based Fluorescent Probes for the Detection of Bacterial Species

“…In addition, they offer a complementary strategy to smart wound technologies and point of care (PoC) devices [11] . Current small‐molecule fluorescent probes utilise enzyme‐based biomarkers to facilitate the detection of pathogenic bacteria, [12] which include elastases, [10e] phosphatases, [13] glycosidases, [14] proteases [15] and lipases [16]…”