Lect. 2 Enterobacteriaceae -- Klebsiella, Raoultella, Enterobacter, Serratia

Common characteristics of Klebsiella, Raoultella, Enterobacter, and Serratia

• H2S =

• Phenylalanine (TDA) =

• VP +

• Lactose +

• Citrate +

Klebsiella and Raoultella results for:

• Citrate

• KCN broth

• H2S

• Phenylalanine deamination (TDA)

• urease

• Indole

• MR and VP

• citrate +

• KCN broth =

• H2S =

• TDA =

• some members have slow urease

• IMVC: =, =, +, +

Klebsiella can be isolated from

• wounds, UTIs, liver abscesses, and bacteremia (increased resistance, including carbapenemase)

• most common isolate if you get G= rods in LRT infection of hospitalized patients

Virulence factor of Klebsiella pneumoniae

polysaccharide capsule (prevent phagocytosis and some antimicrobials)

Biochem tests for Klebsiella pneumoniae

• utilizes all sugars +

• urease, VP, citrate: +

• indole =

• lysine decarboxylase +

• ampicillin resistant

How do you differentiate between Klebsiella oxytoca and K. pneumoniae

K. oxytoca is indole (+) while K. pneumoniae is indole (=)

Klebsiella characteristics: motility and capsule

• non-motile

• encapsulated

Raoultella ornithinolytica:

• indole

• ornithine decarboxylase

• capsule?

• indole +

• ornithine decarb +

• capsule +

Raoultella ornithinolytica and R. planticola are found in __

urine, respiratory tract, blood

Most commonly encountered Enterobacter species from wounds, urine (UTIs), blood, CSF

E. cloacae and E. aerogenes (now Klebsiella aerogenes)

E. gergoviae is clinically isolated from __

respiratory samples, rarely blood

Enterobacter (Pantoea) agglomerans can be found in

contaminated IV fluids

Enterobacter (Cronobacter) sakazakii is associated with

• neonatal infections (meningitis) and sepsis, brain abscess

• outbreaks in ICNs

• fyi: documented meningitis and bacteremia from powdered infant formula

• fyi: yellow pigment

Enterobacter characteristics:

• citrate

• KCN broth

• MR

• VP

• ornithine decarboxylase

• lysine decarboxylase

• citrate +

• KCN broth +

• MR =, VP +

• usually ornithine decarb +

• most lysine decarb + (EXCEPT E. cloacae and E. gergoviae)

Enterobacter cloacae characteristics

• variable sugars (typically 2 negative)

• VP +

• Citrate +

• Indole =

• arginine and ornithine decarb +

• motile

• esculin =

Enterobacter aerogenes

• all sugars positive

• VP and citrate +

• esculin +

• lysine and ornithine decarb +

• motile

Pantoea (Enterobacter) agglomerans biochems

• variable sugars

• VP +

• Citrate +

• Indole =

• all decarb =

• motile

Citrobacter are __ organisms

opportunistic

3 main species of Citrobacter

Citrobacter freundii, Citrobacter koseri, Citrobacter amalonaticus

Citrobacter freundii is associated with

• UTI

• pneumonia

• intraabdominal abscess

• septicemia (related to contaminated IV fluids)

• wounds

Citrobacter koseri is associated with

• UTI

• neonatal meningitis

• brain abscess

Citrobacter amalonaticus is associated with

UTI and wounds

Biochems for Citrobacter freundii:

• sugars

• decarboxylases

• Indole

• VP

• H2S

• Citrate

• ONPG

• urease

• variable sugars

• decarboxylase negative (for all)I

• indole (=)

• VP (=)

• H2S +

• Citrate +

• ONPG +

• slow urease +

2 kinds of test to distinguish Citrobacter freundii from Salmonella

1. Decarboxylate lysine: C. freundii (=), Salmonella (+ for most)

2. Urease: C. freundii (+ for most), Salmonella (=)

Citrobacter koseri biochems:

• sugars

• decarboxylases

• H2S

• VP

• Indole

• Citrate

• urease

• variable sugars and decarboxylases

• H2S (=)

• VP =

• indole +

• Citrate +

• slow urease +

Serratia is seen as a contaminant of __

blood products

What temperature does Serratia have a red pigment usually

25C

T or F: Serratia is resistant to a wide range of antimicrobials

True

What kind of healthcare setting units tend to have outbreaks of Serratia

Special units like Nursery, cardiac surgery, burn unit

Serratia is ONPG __ EXCEPT for _

• +

• S. fonticola

Prodigiosin

pink/red pigment produced by Serratia marcescens at room temp

Serratia marcescens biochems:

• sugars

• VP

• Citrate

• Esculin

• indole

• MAL

• lysine and ornithine decarboxylase

• pigment?

• variable sugars

• VP +

• Citrate +

• Esculin +

• Indole =

• MAL =

• Lys and Orn +

• red pigment

Serratia odorifera smells like

rotten potatoes

Where are the 2 biogroups of Serratia odorifera found?

• Biogroup 1: respiratory

• Biogroup 2: blood and CSF

Biogroup 1 of Serratia odorifera biochems are positive for __

• sucrose

• raffinose

• ornithine

• indole (60%)

Biogroup 2 Serratia odorifera biochems:

• Negative for:

  • sucrose

  • raffinose

  • ornithine

Hafnia biochems:

• oxidase

• indole

• nitrate reduction

• motility

• appearance on XLD agar

• oxidase =

• indole =

• nitrate reduction +

• Motile (+) — more pronounced at 30C than 37C

• some are pink or red on XLD

Edwardsiella tarda:

• urease

• lysine decarb

• H2S

• indole

• Citrate

• clinical manifestations

• urease =

• lysine +

• H2S +

• indole +

• Citrate = (no growth)

• bacteremia + wound infections

Proteus, Morganella, and Providencia are part of normal __

intestinal microbiota

Key biochem reactions for Tribe Proteeae (Proteus, Morganella, Providencia)

• PAD +

• nonlactose fermenters

• TDA + (phenylalanine deaminase)

• motile

• VP (=) EXCEPT one

Proteus mirabilis and P. vulgaris may be isolated from

urine, wounds, ear, and blood infections

Unique motility pattern of Proteus and smell

• swarming

• burnt chocolate odor

Proteus mirabilis and proteus vulgaris:

• lactose

• urease

• H2S

• lactose =

• urease +

• H2S + (most)

Ways to differentiate P. mirabilis and P. vulgaris

1. Indole:

• P. mirabilis =

• p. vulgaris +

2. Ornithine: P. mirabilis (+), P. vulgaris (=)

3. Sugars:

• Glucose: P. mirabilis

• Gucose and sucrose: P. vulgaris

  • Therefore: acid/acid in TSI agar

Does proteus swarm on MAC

no

Proteus mirabilis:

• sugars

• indole

• ONPG

• urea

• H2S

• ornithine

• TDA

• sugar: only Glucose +

• indole =

• ONPG =

• Urease +

• H2S +

• ornithine +

• TDA +

Proteus vulgaris:

• sugars

• urease

• H2S

• indole

• TDA

• decarb

• ONPG

• glucose, sucrose +

• Urease +

• H2S +

• indole +

• TDA +

• decarb =

• ONPG =

Proteus penneri is indole __

indole = (like P. mirabilis)

What kind of facilities do you find Proteus penneri in

• long term care facilities

• hospitals

T or F: Proteus penneri is highly resistant and an invasive pathogen that are abnormalities in urinary tract and stool

true.

Providencia rettgeri is a __ pathogen and is occasionally in nosocomial outbreaks

urinary tract

Providencia can be isolated from urine cultures and notably are part of outbreaks in __

burn units

Describe colonies of Providencia

• colorless

• flat

• do NOT swarm (but all species are motile)

Providencia rettgeri:

• sugars

• Urease

• citrate

• TDA

• H2S

• decarb

• ONPG

• varible sugars

• urease +

• citrate +

• TDA +

• H2S =

• decarb all =

• ONPG =

Providencia stuartii:

• sugars

• citrate

• TDA

• urease

• H2S

• decarb

• ONPG

• variable sugars

• citrate +

• TDA +

• urease =

• H2S =

• all decarb =

• ONPG =

Unique diseases caused by Morganella morganii

• neonatal sepsis

• brain and tubo-ovarian abscesses

• fyi: UTI infections and possibly diarrhea

Does Morganella morganii swarm

No but it is motile

Morganella morganii:

• sugar

• urease

• indole

• ornithine

• TDA

• ONPG

• Citrate

• glucose only +

• urease +

• indole +

• ornithine +

• TDA +

• ONPG =

• citrate =

What clinical symtpoms are associated with Plesiomonas

• fever, vomiting or both

• abdominal pain

Plesiomonase is found in

• soil and aquatic environments

• among warm and cold blooded animals

• NOT normal flora for us (pathogen)

3 maojr clinical types of gastroenteritis caused by Plesiomonas

1. more common watery or secr3etory diarrhea

2. subacute or chronic disease that lasts 14 days to 2 or 3 months

3. more invasive dysenteric form that resemble colitis

Notable extraintestinal infections cause by plesiomonas

• meningitis in neonates

• septicemia

• shock

What trait completely distinguishes Plesiomonas from all other enterobacteriaceae

Plesiomonas is oxidase (+) while all other enterbacteriaceae is =

Plesiomonas:

• oxidase

• indole

• glucose

• can it produce gas from glucose?

• encapsulated?

• motility

• OXIDASE + !!!!

• indole +

• glucose +

• does NOT produce gas from glucose

• NO capsules

• motile