Common Opportunistic and Pathogenic Enterobacteriaceae

What 5 Enterics are LFs?

(Elephants Keep Keen Knowledge Eternally)

1. E. coli

2. Klebsiella pneumoniae

3. Klebsiella oxytoca

4. Klebsiella aerogenes

5. Enterobacter cloacae

What Enteric is the most common cause of UTIs, nosocomial infections, and meningitis in neonates?

E. coli

Identify this organism:

TSI: A/A

Motility: +

Indole: +

Ornithine: +

CIT: -

LYS: -

PD: -

E. coli (note that only LF that is CIT - and MIO +)

What strain of E. coli causes hemolytic uremic syndrome (HUS)?

E. coli 0157:H7

What media is used to culture E. coli 0157:H7?

SMAC (MAC + sorbitol)

How do you differentiate K. pneumoniae from K. oxytoca?

K. pneumoniae: IND -

K. oxytoca: IND +

Identify this organism:

TSI: A/A

Motility: -

Indole: -

Ornithine: -

CIT: +

LYS: +

PD: -

Klebsiella pneumoniae (note that only LF that is MIO -)

Identify this organism:

TSI: A/A

Motility: -

Indole: +

Ornithine: -

CIT: +

LYS: +

PD: -

Klebsiella oxytoca

How do you differentiate K. aerogenes from E. cloacae?

K. aerogenes: LYS: +

E. cloacae: LYS -

Identify this organism:

TSI: A/A

Motility: +

Indole: -

Ornithine: +

CIT: +

LYS: +

PD: -

Klebsiella aerogenes

Identify this organism:

TSI: A/A

Motility: +

Indole: -

Ornithine: +

CIT: +

LYS: -

PD: -

Enterobacter cloacae

What group of Enterics are urease +?

PD + group

What 4 organisms are PD +?

(Pandas Play Music Perfectly)

1. Proteus mirabilis

2. Proteus vulgaris

3. Morganella

4. Providencia

What 2 PD + Enterics produce H2S?

1. Proteus mirabilis (ORN +)

2. Proteus vulgaris (ORN -)

How do you differentiate Proteus mirabilis from Proteus vulgaris?

NLFs, PD +, H2S producers:

P. mirabilis: IND -, ORN +, CIT +

P. vulgaris: IND +, ORN -, CIT -

What Enteric “swarms” on SBA and is an NLF on MAC?

Proteus mirabilis

Identify this organism:

TSI: K/A H2S

Motility: +

Indole: -

Ornithine: +

CIT: +

LYS: -

PD: +

Proteus mirabilis

Identify this organism:

TSI: K/A H2S

MIO: turbid, red, yellow

Motility: +

Indole: +

Ornithine: -

CIT: -

LYS: -

PD: +

Proteus vulgaris

What 2 PD + Enterics do NOT produce H2S?

1. Providencia species

2. Morganella

How do you differentiate Providencia species from Morganella?

NLFs, PD +, NO H2S:

Providencia species: ORN -, CIT +

Morganella: ORN +, CIT -

Identify this organism:

TSI: K/A

Motility: +

Indole: +

Ornithine: -

CIT: +

LYS: -

PD: +

Providencia species

Identify this organism:

TSI: K/A

Motility: +

Indole: +

Ornithine: +

CIT: -

LYS: -

PD: +

M. morgani

What 3 Enterics produce H2S and are PD -?

(Sloths Sing Carelessly)

1. Salmonella typhi

2. Salmonella enterica

3. Citrobacter freundii

Which 2 types of media are selective for Salmonella and Shigella?

HE and XLD

What 2 PD -, H2S producers are LYS +?

1. Salmonella typhi

2. Salmonella enterica

What genera of Enteric causes typhoid fever?

Salmonella

How do you differentiate Salmonella typhi from Salmonella enterica?

NLFs, PD -, H2S producers:

Salmonella typhi: ORN -, CIT -

Salmonella enterica: ORN +, CIT +

What Enteric is characterized by an H2S moustache?

Salmonella typhi

Identify this organism:

TSI: K/A H2S

Motility: +

Indole: -

Ornithine: -

CIT: -

LYS: +

PD: -

Salmonella typhi

Identify this organism:

TSI: K/A H2S

Motility: +

Indole: -

Ornithine: +

CIT: +

LYS: +

PD: -

Salmonella enterica

What PD -, H2S producers is LYS -?

Citrobacter freundii

Identify this organism:

TSI: K/A H2S

Motility: +

Indole: -

Ornithine: -

CIT: +

LYS: -

PD: -

Citrobacter freundii

What 4 Enterics are NLFs that are PD - and do NOT produce H2S?

(Sneaky Snails Yell Cheerfully)

1. Shigella species

2. Serratia marcescens

3. Yersinia enterocolitica

4. Citrobacter koseri

What Enteric causes bacillary dysentery?

Shigella species

What Enteric has all negative biochemical results?

Shigella species

Identify this organism:

TSI: K/A

Motility: -

Indole: -

Ornithine: -

CIT: -

LYS: -

PD: -

Shigella species

What Enteric is DNAse + and can produce red pigmented colonies?

Serratia marcescens

How do you differentiate Serratia marcescens from other PD -, non H2S producing NLFs?

ORN +, CIT +, LYS +

Identify this organism:

TSI: K/A

Motility: +

Indole: -

Ornithine: +

CIT: +

LYS: +

PD: -

Serratia marcescens

How do you differentiate Citrobacter koseri from Yersinia enterocolitica?

NLFs, PD -, NO H2S:

Citrobacter koseri: CIT +

Yersinia enterocolitica: CIT -

Identify this organism:

TSI: K/A

Motility: +

Indole: +

Ornithine: +

CIT: +

LYS: -

PD: -

Citrobacter koseri

What Enteric is known as psuedoappendicitis?

Yersinia enterocolitica

What Enteric is motile in cold environments (25C)?

Yersinia enterocolitica

Identify this organism:

TSI: K/A

Motility: +

Indole: +

Ornithine: +

CIT: -

LYS: -

PD: -

Yersinia enterocolitica

What Enteric causes the plague/Black death?

Yersinia pestis