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
±	–	–	–	+	–	–	oxidase +	Plesiomonas shigelloides
	–	–	+	±	+	–		Yersinia enterocolitica
–	+	+		–	+	+/±		Proteus mirabilis
		+		+	+	–/±		Proteus vulgaris
		± with gas	–	–	+	–		Proteus penneri
		–/± with gas	–	+	+	–		Morganella morganii
		– no gas	+	+	+	+		Providencia rettgeri
		– no gas	–	+	–	+		Providencia stuartii
	–	±	+	±	–/±	+/±		Citrobacter species
		–	+	+	–	–		Escherichia coli (inactive)
		–	+	–	–	+		Hafnia species
		+/±	+	–	–	±		Salmonella species
		–	+	–	–	–		Shigella species (other than S. dysenteriae)
		–	+	–	–	+		Serratia marcescens
		+	–	+	–	–		Edwardsiella tarda
		–	–	–	–	–		Shigella dysenteriae