TABLE 1.

Laboratory methods to differentiate several pathogenic and nonpathogenic species of Neisseria that may be misidentified as N. meningitidis^a

Neisseria sp.	Growth on sheep blood	Yellow pigment	Acid from glucose	Acid from maltose	Colistin resistance	Enzyme productionb
N. meningitidis	+	−	+	+	+	GGTc
N. gonorrhoeae	w	−	+	−	+	PAP
N. polysaccharea	+	−	+	+	+/−	PAP
N. lactamica	+	+	+	+	+	B-Gal
N. sicca	+	−	+	+	−	PAP
N. subflava	+	+	+	+	−d	GGT or PAP

^a+, yes; w, weak or slow growth; +/−, a minority of strains exhibit this phenotype; −, no.

^bGGT, gamma-glutamyl aminopeptidase; PAP, hydroxyl-prolyl aminopeptidase; B-Gal, beta-galactosidase.

^cGGT-negative strain reported in reference 2.

^dN. subflava bv. perflava may exhibit resistance.