Bacterium anitratum is a Gram-negative bacillus having many characteristics of the Enterobacteriaceae but differing in its inability to reduce nitrate. In many laboratories it is still reported as an unidentified Gram-negative bacillus, and its doubtful position in bacteriologic nomenclature has also received some attention, with varying opinions.1-3 Since the original descriptions by Schaub and Hauber 4 and Stuart et al.,5 several papers have described its isolation, cultural and biochemical characteristics, and sensitivities to antibiotics.6-8 Little information has been provided in connection with its pathogenicity for man. The purpose of this paper is to report three cases in which B. anitratum appeared to play a significant pathogenic role.
A. Identification of Bacterium Anitratum.
—The organism is a nonmotile Gram-negative bacillus, with marked bipolar staining. It grows well on desoxycholate agar, with no, or very slow, lactose fermentation and is inhibited on SS (Difco) agar. In