20 - Listeria and Erysipelothrix

Abstract

Publisher Summary This chapter focuses on the genera Listeria and Erysipelothrix, the species of which are similar in a number of aspects. The organisms are slender, gram-positive, nonsporing, facultatively anaerobic, and fermentative rods. Listeria monocytogenes and Erysipelothrix rhusiopathiae are the important pathogenic species. Listeria ivanovii is the only species other than Listeria monocytogenes that is frankly pathogenic for animals, including humans. Listeria ivanovii is pathogenic for mice experimentally and for pregnant sheep, in which it causes abortion. Listeria innocua has been isolated from soil, plants, and human and animal feces. Organism of the species Listeria welshimeri has been recovered from soil and decaying vegetation. Organism of the species Listeria seeligeri has been recovered from soil, vegetation, and animal feces. The natural habitats of Listeria munayi and Listeria grayi are soil and vegetation. One of the species of Erysipelothrix is Erysipelothrix rhusiopathiae, which is an important pathogenic species. Both Erysipelothrix rhusiopathiae and Listeria monocytogenes are capable of survival in the soil and existing in the animal in commensal and carrier states. The chapter discusses the pathogenicity, isolation procedures, cultural characteristics, and identification of these two genera.