TABLE 2.

Differential phenotypic characteristics of Aggregatibacter species

Characteristic	Findinga
	A. actinomycetemcomitans	A. aphrophilus	A. segnis	A kilianii sp. nov.
Porphyrin synthesis (X factor not required)	+	+	+	+
NadV synthesis (V factor not required)	+	v	0	+
Catalase	+	0	v	0
Hemolysis	0b	0	0	0
β-Galactosidase (ONPG)	0	+	v	+
Tryptophanase (indole)	0	0	0	0
Urease	0	0	0	0
Ornithine decarboxylase	0	0	0	0
Proline arylamidase	0	v	0	+
Alanine-phenylalanine-proline arylamidase	0	0	0	+
Phenylphosphonate	v	+	v	+
Acid from
Maltotriose	v	v	v	0
N-Acetylglucosamine	v	0	0	+

^a+, ≥90% of strains positive; v, 11 to 89% of strains positive; 0, ≤10% of strains positive.

^bIsolates with overexpression of leukotoxin may exhibit a zone of hemolysis (35).