[Phenotypes and epidemiological markers of Salmonella typhimurium]

Salmonella typhimurium is the most often encountered serotype. The need for numerous epidemiological markers seems particularly obvious. The purpose of this study was to extend the biotyping patterns previously published and usually restricted to some biochemical characters. 192 strains of S. typhimurium, selected as representative of 6 continental French regions and 4 ecological sources, were studied by means of 203 tests, including the assimilation of 147 carbon substrates. An analysis of the results showed that 52 biochemical or nutritional tests could be used as markers during the survey of an epidemic. In addition, 18 of these tests permitted to delineate three polythetic phenons, in which the ecological origin of strains was statistically different. The identification of these phenotypes, before testing markers, could be a useful first step for the investigation of studied strains.