TABLE 4.
Differentiating characteristics of gram-negative bacteria that are or resemble critical biological agentsa
| Organism | Gram stainb | Resultc
|
||||
|---|---|---|---|---|---|---|
| SBA | MAC | Oxidase | Urease | Motility | ||
| Brucella spp.d | CB | + | V | +/− | + | − |
| Psychrobacter phyenylpyruvicusd | CB | + | + | + | + | − |
| Oligella ureolytica | CB | + | V | + | + | V |
| Bordetella bronchiseptica | CB, R | + | + | + | + | + |
| Actinobacillus spp. | CB | + | V | +/− | +/− | − |
| Haemophilus influenzae | CB | − | − | V | V | − |
| Haemophilus aphrophilus | CB, R | + | −/+ | −/+ | − | − |
| Francisella tularensis | CB | +/−e | − | − | − | − |
| Yersinia pestis | R | + | + | − | − | − |
| Acinetobacter spp. | CB | + | + | − | V | −/+ |
The names of possible agents of bioterroism are in bold type. Information in this table was complied from references 43, 45, and 51 and information accessible through the CDC's bioterrorism preparedness site (www.bt.cdc.gov).
CB, coccobacilli; R, rods. SBA, growth on sheep blood agar; MAC, growth on MacConkey agar.
+, positive; −, negative; +/−, most strains positive; −/+, most strains negative; V, variable reactions.
Brucella spp. cells stain faintly in the Gram stain, while the phenotypically similar Psychrobacter phenylpyruvicus (formerly Moraxella phenylpyruvica) exhibits more intense staining.
F. tularensis may be recovered initially on blood agar but cannot be successfully subcultured on this medium.