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CULTIVATION MEDIA IN BACTERIOLOGY I

MacConkey agar

What is agar plate?

MacConkey agar plate

escherichia coli colonies on MacConkey agar

Escherichia coli
on MacConkey agar
(lactose positive)

Lactose fermenting
Escherichia coli
on MacConkey agar

appearance of lactose positive colonies on MacConkey

Appearance of lactose positive E.coli on MacConkey

MacConkey agar: lactose positive colonies
of Escherichia coli

Klebsiella pneumoniae
on MacConkey:
lactose positive

Colonies of
Klebsiella pneumoniae on MacConkey agar
(lactose positive)

Klebsiella and salmonella on MacConkey agar

Klebsiella pneumoniae and Salmonella enterica
on MacConkey agar:
lactose + and -

Serratia marcescens
on MacConkey agar:
lactose negative

Lactose negative Pseudomonas aeruginosa
on MacConkey agar

lactose negative colonies of pseudomonas on MacConkey agar

Pseudomonas aeruginosa
on MacConkey agar
(lactose negative)

MacConkey Agar

Use: Moderately selective culture medium for the detection of coliform organisms and enteric pathogens

GROWTH

INHIBITION OF GROWTH

LACTOSE POSITIVE
examples

LACTOSE NEGATIVE
examples

Escherichia coli (most strains)
Klebsiella pneumoniae
Entrobacter cloacae

Salmonella enterica ssp. enterica
Shigella spp.
Proteus spp.
Citrobacter freundii (some strains)
Morganella morganii
Providencia spp.

staphylococci
streptococci
enterococci

Crystal violet and bile salts in medium inhibit growth of Gram-positive microorganisms

BACTERIUM	TYPICAL GROWTH ON MACCONKEY AGAR
Escherichia coli	Pink to rose-red. Colonies may be surrounded by a zone of precipitated bile.
Enterobacter cloacae	Pink, mucoid.
Klebsilla pneumoniae	Pink, mucoid.
Proteus	Colorless.
Pseudomonas aeruginosa	Colorless to pink.
Salmonella and Shigella	Colorless.
Gram-positive bacteria	No growth to slight growth (pale pink).

MacConkey agar on Wikipedia

www.microbelibrary.org

Endo Agar

Endo agar plate

Lactose positive colonies
of Escherichia coli
on Endo agar

klebsiella colonies on Endo(lactose fermentation)

Lactose positive colonies
of Klebsiella pneumoniae
on Endo agar

Colonies of Escherichia coli
on Endo agar
(lactose positive)

Colonies of Klebsiella pneumoniae
on Endo agar
(lactose positive)

Colonies of
Escherichia coli on Endo agar
(lactose positive, metallic sheen)

lactose fermentation on Endo with E.coli

E.coli on Endo agar
(lactose positive, metallic sheen)

Klebsiella pneumoniae and Escherichia coli on Endo agar (lactose positive)

Klebsiella pneumoniae
on MacConkey agar (lactose positive)

lactose negative colonies of salmonella on Endo

Lactose negative colonies
of Salmonella enterica
on Endo agar

Shigella flexneri on Endo agar
(lactose negative)

Colonies of
Shigella flexneri on Endo agar
(lactose negative)

Endo Agar

Use: Moderately selective culture medium for the detection and confirmation of coliforms and other enteric microorganisms

GROWTH

INHIBITION OF GROWTH

LACTOSE POSITIVE
examples

LACTOSE NEGATIVE
examples

Escherichia coli (most strains)
Klebsiella pneumoniae
Entrobacter cloacae

Salmonella enterica ssp. enterica
Shigella spp.
Proteus spp.
Citrobacter freundii (some strains)
Morganella morganii
Providencia spp.

staphylococci
streptococci
enterococci

Inhibition of Gram-positive microorganisms is achieved by the sodium sulfite and basic fuchsin contained in the formulation

BACTERIUM	TYPICAL GROWTH ON ENDO AGAR
Escherichia coli	Colonies pink to rose-red with/without green metallic sheen.
Enterobacter cloacae	Pink to rose-red, mucoid.
Klebsilla pneumoniae	Pink to rose-red, mucoid.
Proteus	Colorless.
Pseudomonas aeruginosa	Colorless.
Salmonella and Shigella	Colorless.
Gram-positive bacteria	No growth to slight growth (pale pink to red).

Endo agar on Wikipedia

Deoxycholate Citrate Agar

Klebsiella pneumoniae
on Deoxycholate Citrate Agar (DCA)
(lactose positive)

Pseudomonas aeruginosa
on Deoxycholate Citrate Agar
(lactose negative)

Proteus mirabilis on Deoxycholate Citrate Agar
(lactose negative)

Salmonella enterica
on Deoxycholate Citrate Agar
(lactose negative,
H₂S positive)

deoxycholate citrate agar lactose fermentation

Lactose negative and lactose positive colonies of bacteria on Deoxycholate Citrate Agar (DCA)

Klebsiella pneumoniae
on Deoxycholate Citrate Agar
(lactose positive)

Proteus mirabilis
on Deoxycholate Citrate Agar
(lactose negative)

pseudomonas on deoxycholate citrate agar

Pseudomonas aeruginosa
on Deoxycholate Citrate Agar
(lactose negative)

proteus and pseudomonas on deoxycholate citrate agar

Lactose negative colonies of Proteus mirabilis (larger)
and Pseudomonas aeruginosa on Deoxycholate Citrate Agar

Lactose negative, H₂S positive colonies of Salmonella enterica on Deoxycholate Citrate Agar

lactose fermentation on deoxycholate agar

Lactose negative, H₂S positive colonies of Salmonella enterica, lactose negative colonies of Proteus mirabilis and lactose positive colonies of Escherichia coli

lactose negative colonies on deoxycholate agar

lactose negative,hydrogen sulfide positive colonies on deoxycholate agar

Lactose negative, hydrogen sulfide positive colonies of Salmonella enterica and lactose negative colonies of Pseudomonas aeruginosa

Deoxycholate Citrate Agar

Use: Isolation of Salmonella and Shigella species; moderately selective.

GROWTH

INHIBITION OF GROWTH

LACTOSE POSITIVE
examples

LACTOSE NEGATIVE
examples

Escherichia coli (most strains)
Klebsiella pneumoniae
Entrobacter cloacae

Partial to complete inhibition.

Salmonella enterica ssp. enterica
Shigella spp.
Proteus spp.
Pseudomonas aeruginosa

Completely suppress the Gram-positive microbial flora.

Inhibition of Gram-positive microorganisms and coliforms is achieved by the deoxycholate and citrate contained in the formulation.

BACTERIUM	TYPICAL GROWTH ON DEOXYCHOLATE CITRATE AGAR
Salmonella spp.	Colorless colonies with or without black centers (H₂S production).
Shigella spp.	Colorless.
Proteus	Colorless colonies with or without black centers (H₂S production). Partial to complete inhibition.
Escherichia coli	Pink with/without bile precipitate.
Enterobacter cloacae	Pink. Partial to complete inhibition.
Klebsiella pneumoniae	Pink. Partial to complete inhibition.
Pseudomonas aeruginosa	Colorless. Partial to complete inhibition.
Gram-positive bacteria	No growth.

Deoxycholate Citrate Agar on Wikipedia

Blood Agar

Columbia Sheep Blood Agar

Beta-hemolysis on blood agar (Staphylococcus aureus)

Beta-hemolysis on blood agar (Streptococcus pyogenes)

Beta-hemolysis on blood agar (Listeria ivanovii)

Beta-hemolysis (Streptococcus pyogenes) and gamma-hemolysis (Enterococcus faecalis) on blood agar

Alpha-hemolysis on blood agar (Streptococcus pneumoniae)

Alpha-hemolysis on blood agar (Streptococcus pneumoniae)

Gamma-hemolysis on blood agar (Escherichia coli)

Gamma-hemolysis on blood agar (Klebsiella pneumoniae)

Gamma-hemolysis on blood agar (Enterococcus faecalis)

Non-hemolytic colonies on blood agar
(Salmonella enterica)

Gamma-hemolysis on blood agar (Escherichia coli)

Alpha-hemolysis on blood agar (Streptococcus pneumoniae)

Alpha-hemolysis on blood agar (viridans streptococci)

Beta-hemolysis on blood agar (Streptococcus agalactiae)

Beta-hemolytic colonies on blood agar
(Staphylococcus aureus)

Beta-hemolysis on blood agar (Streptococcus pyogenes)

Gamma-hemolysis and beta-hemolysis on blood agar (Enterococcus faecalis and Streptococcus pyogenes)

Blood agar on Wikipedia

Hemolysis on Wikipedia

www.microbelibrary.org

Mueller Hinton Agar

Mueller Hinton agar

Klebsiella pneumoniae
on Mueller Hinton agar

Escherichia coli
on Mueller Hinton agar

Stenotrophomonas maltophilia
on Mueller Hinton agar

Staphylococcus aureus
on Mueller Hinton agar

mueller hinton agar with variovorax paradoxus

Variovorax paradoxus
on Mueller Hinton agar

mueller hinton agar and chryseobacterium indologenes

Chryseobacterium indologenes
on Mueller Hinton agar

Chryseobacterium indologenes
and an actinomycete
on Mueller Hinton agar

Yellowish colonies of
Stenotrophomonas maltophilia
on Mueller Hinton agar

Mucoid colonies of
Klebsiella pneumoniae
on Mueller Hinton agar

mueller hinton agar staphylococcus aureus

Yellow colonies of
Staphylococcus aureus
on Mueller Hinton agar

enterobacter cloacae mueller hinton agar

Enterobacter cloacae
on Mueller Hinton agar

mueller hinton agar mycobacterium(rapidly growing)

Rapidly growing
Mycobacterium sp.
on Mueller Hinton agar

mycobacterium on mueller hinton agar with

Colonies of Mycobacterium sp.
on Mueller Hinton agar
(eugonic growth)

mycobacterium colonies on mueller hinton agar

Mycobacterium sp.
on Mueller-Hinton agar

mycobacterium chelonae colonies on mueller hinton agar

Mycobacterium chelonae
on Mueller Hinton agar
(disgonic growth)

Mueller Hinton agar on Wikipedia

Disk Diffusion Test on Mueller Hinton Agar

antibiotics susceptible bacterium(bacteria)

Disk Diffusion Test
on Mueller-Hinton Agar

diffusion test with antibiotic discs, gentamicin resistant bacterium

Bacterium susceptible
to ampicillin and resistant to gentamicin

Good susceptibility to antibiotics

inhibition zones in antibiotic disks diffusion test

Kirby-Bauer antibiotic testing
on Mueller-Hinton Agar

disk diffusion test with escherichia coli

Disk Diffusion Test
on Mueller-Hinton Agar
(susceptible strain, ampicillin resistant)

Bacterium resistant to 3 out of 6 tested antibiotics

Alcaligenes faecalis
resistant to 4 out of 6 tested antibiotics

Pseudomonas aeruginosa:
subpopulations of cefotaxime
resistant bacteria

Pseudomonas aeruginosa:
susceptible to ciprofloxacin,
resistant to the rest
(small inhibition zone around tetracycline)

Klebsiella pneumoniae:
good susceptibility
to tested antibiotics
(ESBL screening)

Klebsiella pneumoniae:
double disk synergy test
(ESBL positive)

Staphylococcus aureus:
E-test

Antibiotic testing (on Wikipedia)

E-test(on Wikipedia)

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