Erwinia chrysantum

Erwinia chrysanthemi is a gram-negative bacillus that belongs to the family Enterobacteriaceae. It is a close relative of E. coli and other animal pathogens that include Salmonella, Shigella, Klebsiella, Proteus and Yersinia. Members of this family are facultative anaerobes, able to ferment sugars to lactic acid, have nitrate reductase, but lack oxidases. Even though many clinical pathogens are part of the Enterobacteriaceae family, most members of this family are plant pathogens.

In the natural plant environment, Erwinias cause plant maladies such as necrosis, blight and “soft rot,” a progressive tissue maceration. Erwinia chrysanthemi contains many pectinases that are able to macerate and break down the plant cell wall material. This exposed part of the plant releases nutrients that can facilitate bacterial growth. Commonly infected plants include potato tubers, bulbs of vegetables, and ornamental crops.