Chromogenic and fluorogenic indicators and substrates in diagnostic microbiology

Abstract

Summary The biochemical activity of bacteria can be detected by a change in the light absorption of product/substrate or the reaction of either with an indicator. Microbiology can make use of the advances in inorganic chemistry applied to other specialities for the development of novel indicators. Compounds have been developed that yield brightly coloured or fluorescent products when acted on by bacterial enzymes or when reacted with specific bacterial metabolites. The new compounds produce rapid results which are clearly seen and which are often more specific than previous methods. Improvement in the heat stability of reagents and their use in simple tests is bringing the greater use of these newer indicators into the clinical microbiology laboratory, although their chemical structure may be retained by the manufacturer. The aim of this review is to give a brief overview of the expanding chemistry currently available and highlight areas where developments are to be expected.