Methods used for the isolation, enumeration, characterisation and identification of Enterococcus spp.: 1. Media for isolation and enumeration

Due to their significance in food, feed, environmental and clinical samples, the detection and enumeration of enterococci have become an important issue not only in daily routine but also in current research activities. Several media and protocols have been published for diverse purposes, but there is no single method, which universally meets all requirements. Depending on the nature of the accompanying microflora and its level, certain substrates and modifications thereof have to be used, taking into account various drawbacks and advantages. In addition to the historical applications (examination of water, different kinds of foods, intestinal and other clinical specimen), the detection of vancomycin-resistant enterococci (VRE) has become an important task, since VRE have found to be frequently involved in nosocomial infections. Moreover, contradictory methodological recommendations can be found in the literature. This paper will give a systematic survey of the different media and methods proposed during the last two decades. Emphasis is placed on compositional details and on specific applications of the media described.