Enterobacteriaceae

• A family of Gram-negative bacteria
• Non-spore-forming, glucose-fermenting facultative anaerobes
• Medically important bacteria within the family includes:
  • Citrobacter species
  • Edwardsiella species
  • Enterobacter species
  • Escherichia coli and Shigella species
  • Hafnia species
  • Klebsiella species
  • Morganella morganii
  • Panoea agglomerans
  • Plesiomonas shigelloides
  • Proteus species
  • Providencia species
  • Salmonella enterica
  • Serratia marcescens
  • Yersinia species

Identification

Lactose	PPA	H2S	Mannitol	Indole	Urease	Growth on Citrate	Other Tests	Organism
+	–	–	+	+	+	+	nonmotile, methylene red –	Klebsiella oxytoca
+	–	–	+	+	+/±	+	motile, methylene red +	Citrobacter koseri
+	–	–	+	+	–	–		Escherichia coli
+	–	+	+	– ±	–/±	+/±	H2S +	Citrobacter freundii
+	–	–	+	–	+	+	A/A with gas	Klebsiella pneumonia
+	–	–	+	–	+/±	+	A/A with gas, AD positive	Enterobacter cloacae
+	–	–	+	–	–	+	A/A with gas, OD positive	Klebsiella aerogenes
–	+	+		–	+	+/±		Proteus mirabilis
–	+	+		+	+	–/±		Proteus vulgaris
–	+	+		–	+	–		Proteus penneri
–	+	–/±	– with gas	+	+	–		Morganella morganii
–	+	–	+ no gas	+	+	+		Proteus rettgeri
–	+	–	– no gas	+	–	+		Proteus stuartii
–	+	–	– with gas	–	+	–		Proteus penneri
–	–		+					Citrobacter species
–	–		+					Escherichia coli (inactive)
–	–		+					Hafnia species
–	–		+					Salmonella species
–	–		+					Shigella species (other than S. dysenteriae)
–	–		+					Serratia marcescens
–	–	+	–	+				Edwardsiella tarda
–	–	–	–	–				Shigella dysenteriae