[Differentiation of clostridia]

162 Clostridium strains (20 species), isolated from clinical specimens, were identified by their morphological, biochemical, and gaschromatographic characteristics. The reliability of the Api 20A system in identifying Clostridium species was studied by performing biochemical tests both in the microsystem and according to the VPI Anaerobic Handbook. 66% of the Clostridium strains could be identified by the Api 20A system supplemented, in accordance with the Api Handbook by other tests such as morphology, lipase and lecithinase production. The following Clostridium species, known as clinically most significant, could be identified by the Api 20A system: Clostridium sordellii and C. sporogenes (92%), C. bifermentans (60%) and C. tertium (78%). Methods which can be used in the clinical laboratory for the identification of Clostridium species are described, i.e. isolation of Clostridium strains from mixed cultures, examination of morphological characteristics, performance of biochemical tests in the Api 20 A system as a micromethod, verification by conventional biochemical test systems and gaschromatographic analysis in special laboratories if necessary.