Family

Family

Enterobacteriaceae

Enterobacteriaceae

PART I

PART I

Genera:

Genera:

Escherichia

Escherichia

,

,

Klebsiella

Klebsiella

,

,

Enterobacter

Enterobacter

General properties of

General properties of

Enterobacteriaceae

Enterobacteriaceae



Gram-negative rods

Gram-negative rods



Non-spore-forming

Non-spore-forming



Peritrichous flagellae

Peritrichous flagellae

(motility) (exceptions!)

(motility) (exceptions!)



Capsules can be

Capsules can be



Facultative anaerobes or

Facultative anaerobes or

aerobes

aerobes



Grow in simple media

Grow in simple media



Ferment glucose and

Ferment glucose and

produce acid

produce acid



Nitrates are reduced to

Nitrates are reduced to

nitrites

nitrites



Oxidase-negative, catalase-

Oxidase-negative, catalase-

positive (exception!)

positive (exception!)

Enterobacteriaceae

Enterobacteriaceae

Lactos
e +

Lactose
-

Flagell
a +

Flagell
a -

Flagell
a +

Flagell
a -

Escherich
ia

Enterobac
ter

Citrobact
er

Serratia

Klebsiel
la

Salmonella

Proteus

Providenci
a

Hafnia

Edwarsiell
a

Shigell
a

Enterobacteriaceae

Enterobacteriaceae

Determinants of

Determinants of

pathogenicity

pathogenicity

Major antigens

Major antigens



K/Vi antigens

K/Vi antigens

(capsular)

(capsular)



H antigens

H antigens

(flagellar)

(flagellar)



O antigens

O antigens

(somatic, in LPS)

(somatic, in LPS)

Virulence factors

Virulence factors



Endotoxin (LPS)

Endotoxin (LPS)



Exotoxins

Exotoxins



Adhesion/colonizati

Adhesion/colonizati

on factors

on factors

(fimbriae)

(fimbriae)



Capsules

Capsules

Endotoxin

Endotoxin

(LPS – lipopolysaccharide)

(LPS – lipopolysaccharide)



Polysaccharide core

Polysaccharide core



O antigen (immunogenic)

O antigen (immunogenic)



Lipid A

Lipid A

(the toxicity of LPS depends on the

(the toxicity of LPS depends on the

structure of lipid A)

structure of lipid A)

Laboratory

Laboratory

identification of

identification of

Enterobacteriaceae

Enterobacteriaceae

species

species



Culture and isolation

Culture and isolation



Biochemical properties [

Biochemical properties [

biotyping

biotyping

]

]

(identification to genera and species)

(identification to genera and species)



Antigenic properties [

Antigenic properties [

serotyping

serotyping

]

]

based on somatic-O, capsular-K and on

based on somatic-O, capsular-K and on

flagella - H antigenes (identification to

flagella - H antigenes (identification to

species and different subgroups of this

species and different subgroups of this

species)

species)

Media for

Media for

Enterobacteriaceae

Enterobacteriaceae



Transporting media

Transporting media



Poorly selecting differential media

Poorly selecting differential media

(Levin’s medium/EMB agar, MacConkey’s

(Levin’s medium/EMB agar, MacConkey’s

medium)

medium)



Moderately selecting differential media

Moderately selecting differential media

(SS agar, Wilson-Blair’s medium)

(SS agar, Wilson-Blair’s medium)



Differential enrichment media

Differential enrichment media

(selenite broth of Leifson = SF broth)

(selenite broth of Leifson = SF broth)



Blood agar

Blood agar

Biochemical

Biochemical

identification of

identification of

Enterobacteriaceae

Enterobacteriaceae

1.

1.

Test on Kligler’s iron agar (KIA)

Test on Kligler’s iron agar (KIA)

2.

2.

Urease activity test

Urease activity test

3.

3.

Test for

Test for

I

I

ndol

ndol

4.

4.

M

M

ethyl red test

ethyl red test

5.

5.

V

V

oges-Proscauer’s test

oges-Proscauer’s test

6.

6.

C

C

itrinating test

itrinating test

7.

7.

IMVC

IMVC

test (3+4+5+6) (for

test (3+4+5+6) (for

E. coli,

E. coli,

Enterobacter

Enterobacter

spp

spp

.

.

)

)

8.

8.

API 20 Enterobacteriaceae (API 20 E)

API 20 Enterobacteriaceae (API 20 E)

Family:

Family:

Enterobacteriaceae

Enterobacteriaceae

(27 generas are included)

(27 generas are included)



Escherichia

Escherichia

spp.

spp.



Klebsiella

Klebsiella

spp.

spp.



Enterobacter

Enterobacter

spp.

spp.



Salmonella

Salmonella

spp.

spp.



Shigella

Shigella

spp.

spp.



Yersinia

Yersinia

spp.

spp.



Proteus

Proteus

spp.

spp.



Citrobacter

Citrobacter

spp.

spp.



Serratia

Serratia

spp.

spp.



Providencia

Providencia

spp.

spp.



Morganella

Morganella

spp.

spp.

Escherichia

Escherichia

coli

coli

General

General

properties

properties



Ferments lactose

Ferments lactose

on

on

MacConkey medium

MacConkey medium



Produses gas when

Produses gas when

fermenting glucose

fermenting glucose



Produces indole when

Produces indole when

breaking down

breaking down

tryptophane

tryptophane



Often hemolytic

Often hemolytic

(particularly urine

(particularly urine

isolates)

isolates)



Fimbriae are present

Fimbriae are present

(motility)

(motility)



Important opport.

Important opport.

pathogen (symbiont)

pathogen (symbiont)

Determinants of

Determinants of

E. coli

E. coli

pathogenicity

pathogenicity



LPS (endotoxin): fever,

LPS (endotoxin): fever,

leucopenia,hypoglycemia, hypotension,

leucopenia,hypoglycemia, hypotension,

shock, perfusion disorder in main

shock, perfusion disorder in main

organs,activation of complement,

organs,activation of complement,

intravascular coagulation)

intravascular coagulation)



Adhesion factors :unique P fimbrial

Adhesion factors :unique P fimbrial

antigens, antigen O

antigens, antigen O



Enterotoxins:

Enterotoxins:



Hemolysins

Hemolysins



Antiphagocytic capsule

Antiphagocytic capsule

E. coli

E. coli

enterotoxins

enterotoxins



Produced by the enterotoxigenic

Produced by the enterotoxigenic

strains of

strains of

E. coli

E. coli

(ETEC) (genes in

(ETEC) (genes in

plasmids):

plasmids):

–

heat-labile toxins (LT-I and LT-II): stimulate

heat-labile toxins (LT-I and LT-II): stimulate

adenyl cyclase – excretion of water and

adenyl cyclase – excretion of water and

chlorides, inhibition of absorption of natrium

chlorides, inhibition of absorption of natrium

–

heat-stable toxin (ST): binds to intracellular

heat-stable toxin (ST): binds to intracellular

guanylyl cyclase causing incerase of intracellular

guanylyl cyclase causing incerase of intracellular

cGMP concentration - disorder in ion transport

cGMP concentration - disorder in ion transport



Produced by the enterohemorrhagic

Produced by the enterohemorrhagic

strains of

strains of

E. coli

E. coli

(EHEC/VTEC):

(EHEC/VTEC):

–

verotoxin (VT) = Shiga-like toxin: inhibiits protein

verotoxin (VT) = Shiga-like toxin: inhibiits protein

synthesis

synthesis

Pathogenicity of

Pathogenicity of

E. coli

E. coli



Gastrointestinal disease

Gastrointestinal disease



Urinary tract infections

Urinary tract infections



Neonatal meningitis (most frequent

Neonatal meningitis (most frequent

factor)

factor)

(esp. capsular strains named

(esp. capsular strains named

E. coli

E. coli

K1)

K1)



Sporadically: sepsis, secondary

Sporadically: sepsis, secondary

pneumonia, iatrogenic and nosocomial

pneumonia, iatrogenic and nosocomial

infections

infections

„

„

Virulence types” of

Virulence types” of

pathogenic

pathogenic

E. coli

E. coli

(gastrointestinal

(gastrointestinal

disease)

disease)



Enterotoxigenic

Enterotoxigenic

E. coli

E. coli

(ETEC)

(ETEC)



Enterohemorrhagic

Enterohemorrhagic

E. coli

E. coli

(EHEC/VTEC)

(EHEC/VTEC)



Enteropathogenic

Enteropathogenic

E. coli

E. coli

(EPEC)

(EPEC)



Enteroadherent

Enteroadherent

E. coli

E. coli

(EAEC)

(EAEC)



Enteroinvasive

Enteroinvasive

E. coli

E. coli

(EIEC/INVEC)

(EIEC/INVEC)

Transmission of

Transmission of

E. coli

E. coli



Fecal-oral route

Fecal-oral route



Food-borne transmission

Food-borne transmission



Endogenous source

Endogenous source

Laboratory diagnosis of

Laboratory diagnosis of

E. coli

E. coli

infection

infection



Culture and isolation of

Culture and isolation of

E. coli

E. coli

(materials:

(materials:

feces, infected tissue, blood, urine);

feces, infected tissue, blood, urine);

culturing on differential medium

culturing on differential medium

(MacConkey’s agar, EMB agar), blood agar

(MacConkey’s agar, EMB agar), blood agar



Biochemical analysis (e.g. glucose

Biochemical analysis (e.g. glucose

fermentation, production of indol and

fermentation, production of indol and

H

H

2

2

S);

S);

biotyping

biotyping

(the result of

(the result of

IMVC

IMVC

test

test

for

for

E. coli

E. coli

: ++--)

: ++--)



Serotyping

Serotyping

– the serotype of a strain is

– the serotype of a strain is

defined by its full antigenic formula, its O,

defined by its full antigenic formula, its O,

K, and H anigens, e. g.

K, and H anigens, e. g.

E. coli

E. coli

O55 K59 H6

O55 K59 H6

Treatment of

Treatment of

E. coli

E. coli

infection

infection



Rehydration with electrolyte-rich liquids

Rehydration with electrolyte-rich liquids



Antibiotic therapy (in children, in extra-

Antibiotic therapy (in children, in extra-

intestinal infections, in chronic infections):

intestinal infections, in chronic infections):

trimethoprim-sulfamethoxasole;

trimethoprim-sulfamethoxasole;

also :

also :



Ampicillin

Ampicillin



Aminoglycosides

Aminoglycosides



Cephalosporins

Cephalosporins

Resistance!

Check
susceptibility

Klebsiella

Klebsiella

spp.

spp.



K. pneumoniae

K. pneumoniae



K. ozaenae

K. ozaenae

(stinking

(stinking

rhinitis = ozena)

rhinitis = ozena)



K. rhinoscleromatis

K. rhinoscleromatis

(inflammation of

(inflammation of

throat, nose, and

throat, nose, and

sinuses mucous

sinuses mucous

membrane =

membrane =

scleroma)

scleroma)



K. oxytoca

K. oxytoca

General properties of

General properties of

Klebsiella

Klebsiella

spp.

spp.



Gram-negative

Gram-negative



NON-MOTILE

NON-MOTILE



Rods

Rods



Mucoid capsule (with

Mucoid capsule (with

antigen K - capsullar

antigen K - capsullar

swelling test)

swelling test)



O antigens

O antigens



On solid medium: mucous

On solid medium: mucous

colonies

colonies



Ferment lactose in

Ferment lactose in

MacConkey’s medium

MacConkey’s medium



Ammonia production

Ammonia production

(urease activity)

(urease activity)

Determinants of

Determinants of

Klebsiella

Klebsiella

spp.

spp.

pathogenicity

pathogenicity



Mucoid antiphagocytic capsule

Mucoid antiphagocytic capsule



LPS

LPS



Plasmid exchange with other

Plasmid exchange with other

Enterobacteriaceae

Enterobacteriaceae

(inconstant

(inconstant

characteristics of antibiotic

characteristics of antibiotic

resistance - ESBL !)

resistance - ESBL !)



Ability to produce toxins similar to

Ability to produce toxins similar to

E.

E.

coli

coli

toxins

toxins