Enterobacteriaceae Flashcards by Filip Garrett

Q

Enterobacteriaceae general characteristics. (3)

A

Growth on MacConkey (aerobic)
Glucose fermentation
Oxidase NEGATIVE

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Q

What is Lipid A?

A

Component of LPS

-Endotoxin

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Q

What is the O antigen?

A

2nd component of LPS

-Bases for Serogrouping

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Q

T/F: Enterobacteriaceae commonly show antimicrobial resistance.

A

True

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Q

Enterobacteriaceae - Families (7)

A

Escherichieae
Edwardsiellae
Salmonella (Shigella)
Citrobactereae
Klebsiellae (Enterobacter/Pantoea/Hafnia)
Proteae (Morganella/Providencia)
Yersiniae

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Q

Enterobacteriaceae - Key Characteristics:

-Reduce Nitrate to Nitrite

A

ALL Enterobacteriaceae

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Q

Enterobacteriaceae - Key Characteristics:

-Strong Lactose Fermentors (Pink/Red on MacConkey)

A

E. coli
Klebsiella
Enterobacter

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Q

Enterobacteriaceae - Key Characteristics:

-Hydrogen Sulfide production (H2S+)

A

Salmonella
Proteus
Citrobacter
Edwardsiella

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Q

Enterobacteriaceae - Key Characteristics:

-Urease Positive (strong)

A

Proteus
Morganella
Providencia

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Q

Enterobacteriaceae - Key Characteristics:

-NONMotile

A

Shigella
Klebsiella
Yersinia at 22C (Nonmotile at 37)

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Q

Enterobacteriaceae - Key Characteristics:

-Voges-Proskaeuer (VP) Positive

A

Klebsiella
Enterobacter
Panteoea
Hafnia

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Q

Enterobacteriaceae - Key Characteristics:

-Phenylalanine Deaminase (PAD) Positive

A

Proteus
Morganella
Providencia

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Q

KIA/TSI Slant Characteristics:

-K/K (red/red)

A

-NO Fermentation (Glucose/Lactose)
-Excludes all Enterobacteriaceae (ALL all Glucose)
DDx:
-Pseudomonas

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Q

KIA/TSI Slant Characteristics:

-K/A (red/yellow)

A

-Glucose Fermentation
-NO Lactose fermentation
DDx:
-Shigella
-Serratia
-Morganella
-Providencia
-Yersinia

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Q

KIA/TSI Slant Characteristics:

-K/A/H2S+ (red/black)

A

-Glucose Fermentation
-NO Lactose Fermentation
-H2S production (black)
DDx:
-Salmonella
-Proteus
-Citrobacter
-Edwardsiella

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Q

KIA/TSI Slant Characteristics:

-A/A (yellow/yellow)

A

-Glucose and Lactose Fermentation
DDx:
-E. coli
-Klebsiella
-Enterobacter

Q

E. coli:

Fermentation
Indole
Enzyme activity

A

E. coli:

Lactose/Glucose Fermentation
Indole POSITIVE
B-glucoronidase activity

Q

E. coli strain capable of producing Shiga Toxin?

Associated Complication
Serotype

A

EHEC (Enterohemorrhagic E. coli)/STEC (Shiga Toxin E. coli)

Hemolytic Uremic Syndrome (HUS)
O157:H7

Q

E. coli strain causing waterborne secretory (watery) diarrhea?

Toxin
Main cause of what?

A

ETEC (Enterotoxigenic E. coli)

Cholera-like Toxins
“Traveler’s Diarrhea”

Q

E. coli strain causing Dysentery?

-Toxin

A

EIEC (Enteroinvasive E. coli)

-Shiga-like toxin (T3SS)

Q

E. coli strain causing Dysentery similar to tha caused by Shigella, but does NOT produce Shigalike Toxin?
-Transmission

A

EPEC (Enteropathogenic E. coli)

-Person-to-Person

Q

E. coli strain causing infant diarrhea in underdeveloped countries?
-U.S. population at risk?

A

EAggEC (Enteroaggregative E. coli)

-HIV+ - Chronic Refractory Diarrhea

Q

EHEC 0157:H7 - Culture characteristic?

A

Does NOT ferment Sorbitol in Sorbitol MacConkey plates

Q

EIEC characteristics Vs. other E. coli.

A

NONmotile
Lactose NONfermenting

*similar to Shigella

Typhoid Fever: - Organisms - Infection site

Salmonella typhi or paratyphi | -Traverse bowel wall and embed within Reticuloendothelial cells of Liver, Spleen and Gall Bladder

What is the most common organisms causing Shigellosis in the U.S.? *Underdeveloped countries

S. sonnei *S. flexneri in underdeveloped countries

Shigella: - Inoculum - Complications (2)

Small inoculum (100-200 bacteria) Complications: - S. dysenteriae can cause HUS - S. flexneri can lead to PostInfectious Arthritis in HLA-B27+ Patients

Klebsiella: - MC manifestation - Characteristic feature

Pneumonia (Necrotizing) | -"Current Jelly" sputum

What Klebsiella spp. is known to cause neonatal sepsis?

K. oxytoca

Klebsiella association with Upper Airway Infection.

Rhinoscleroma (Chronic Granulomatous Dz) | -K. rhinoscleromatis

Yersinia isolation conditions. - Temp - Medium

Isolation at Room Temp. in selective media (CIN agar)

Humans are accidental hosts of Yersinia (zoonotic); what type of climate is this most often found?

Cold climates

Yersinia is an important cause of what?

Transfusion related sepsis

What Yersinia spp. produces necrotizing granulomata resembling TB?

Y. pseudotuberculosis

What Yersinia spp. causes the plague?

Y. pestis