TABLE 3.

Differential characteristics of some catalase-negative, nonmotile, similarly shaped, gram-positive rods^a

Organism	Vancomycin	Hemolysis	Hippurate hydrolysis	Nitrate reduction	Esculin hydrolysis	Gram stain morphology
Bifidobacterium sp.	S	−	+	−	+	Short, irregularly shaped rods, may have rudimentary branching
A. omnicolens	S	−	−	−	+	Short, irregularly shaped rods, may have rudimentary branching
Actinomyces sp.	S	−	V	V	V	Short, irregularly shaped rods, may have rudimentary branching
Lactobacillus sp.	R/V	Alpha	−	V	V	Most are long regular-chaining rods; some are C shaped
G. vaginalis	S	−b	+	−	NA	Small, gram-variable rods

^aData are from references 6, 7, and 13. S, >90% susceptible; R, >90% resistant; V, 10 to 90% positive; −, >90% negative; +, >90% positive; NA, not available.

^bG. vaginalis is beta-hemolytic on human blood medium such as human blood bilayer Tween agar.