Rapid enzymatic characterization of clinically encountered anaerobic bacteria with the API ZYM system

The purpose of this study was to determine if enzyme profiles of anaerobic bacteria, obtained with the API ZYM system, are sufficiently distinctive and reproducible to merit future development of the system and an expanded data base for the four major groups of clinically encountered anaerobes. Of the total 155 clinical isolates and reference strains that were tested, 88% had distinctive patterns. It was possible to differentiate between 89% of the anaerobic gram-negative bacilli, 64% of anaerobic cocci, 100% of anaerobic gram-positive non-sporeforming bacilli and 100% of the Clostridium spp. using only the API ZYM plus Gram reaction, morphology and relation to oxygen. Overall reproducibility for 1,330 enzyme-substrate reactions was 97%. It was concluded that the API ZYM could be a practical system for rapid identification of clinical anaerobe isolates provided that an expanded data base is developed and that certain additional recommended tests are used.