Erwinia and yellow-pigmented Enterobacter isolates from human sources

Sixty-five strains of gram-negative, yellow-pigmented bacilli, including four chromogenic Enterobacter strains and 55 anaerogenic and six aerogenic Erwinia strains, were isolated from human sources. The genus Erwinia contained two groups; an anaerogenic group which produced aggregates of bacteria (symplasmata) in the syneresis water of slant cultures and biconvex bodies in colonies on agar medium, and an aerogenic group which lacked these characteristics. Erwinia was differentiated from Enterobacter, since the latter possessed dihydrolase and decarboxylase activity and demonstrated resistance to cephalothin.