[Biochemical characterization of species in the genus Listeria]

Abstract

Seventy Listeria strains, including L. monocytogenes (30 strains), L. ivanovii (9), L. innocua (11), L. welshimeri (6), L. seeligeri (10), L. grayi (2) and L. murrayi (2) were subjected to biochemical characterization. The biochemical tests selected comprised: Api 50CH, Api 20E and Api Zym strips, hydrolysis of DNA and tween 20, 40, 60, 80, egg yolk agar reaction, growth in the presence of 7,5 and 10% NaCl, growth at 42 degrees C and 45 degrees C, and susceptibility to antibiotics and trypaflavin. No further marker in addition to previously described ones, allowing to distinguish L. monocytogenes, L. ivanovii, L. innocua, L. welshimeri and L. seeligeri could be detected. L. grayi and L. murrayi differed from the other Listeria species by gluconate fermentation, lack of phosphoamidase and acid phosphatase and susceptibility to trypaflavin.