Additional Info For Culture Media Flashcards

1
Q

EKE (rapid lactose fermenters)

A
  • Escherichia
  • Klebsiella
  • Enterobacter
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2
Q

is characterized by a clear, colorless zone around the bacterial colony due to complete lysis of red blood cells.

A

Beta-hemolysis

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3
Q

Common bacteria that show beta-hemolysis include

A

Streptococcus pyogenes (Group A Streptococcus)

Streptococcus agalactiae (Group B Streptococcus).

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4
Q

results in a greenish zone around the colonies, caused by the partial reduction of hemoglobin to methemoglobin.

A

Alpha-hemolysis

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5
Q

Examples of alpha-hemolytic bacteria include

A

Streptococcus pneumoniae

various species of viridans streptococci like Streptococcus mutans.

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6
Q

shows no visible hemolysis around the colonies, indicating no lysis of red blood cells.

A

Gamma-hemolysis (or non-hemolysis)

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7
Q

Bacteria like______display gamma-hemolysis

A

Enterococcus faecalis

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8
Q

McCoy’s Cells

Use

A

Primarily used for the isolation and culture of Chlamydia trachomatis and other related bacteria.

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9
Q
  • Isolates: Selective for Gram-negative bacteria, particularly members of the family Enterobacteriaceae.
A

MacConkey Agar (MAC)

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10
Q

It differentiates lactose fermenters (e.g., Escherichia coli) which appear pink, from non-lactose fermenters (e.g., Salmonella, Shigella) which appear colorless.

A

MacConkey

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11
Q
  • Isolates: Selective for Gram-positive bacteria, specifically Staphylococcus species.
A

Mannitol Salt Agar (MSA)

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12
Q

It differentiates Staphylococcus aureus (which ferments mannitol and turns the medium yellow) from other staphylococci which do not ferment mannitol and leave the medium red.

A

Mannitol Salt Agar (MSA):

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13
Q
  • Isolates: Selective for Gram-negative enteric pathogens.
A

Hektoen Enteric Agar (HEA)

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14
Q

It differentiates Salmonella (which produces black colonies due to hydrogen sulfide production) from Shigella (which produces green colonies).

A

Hektoen Enteric Agar (HEA)

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15
Q
  • Isolates: Selective for Gram-negative enteric pathogens, particularly Salmonella and Shigella.
A

Xylose Lysine Deoxycholate Agar (XLD)

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16
Q

Salmonella* appears with black centers, while Shigella appears red without black centers.

A

Xylose Lysine Deoxycholate Agar (XLD):

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17
Q
  • Isolates: Selective for Neisseria gonorrhoeae and Neisseria meningitidis.
A

Thayer-Martin Agar:

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18
Q

It contains antibiotics to inhibit the growth of contaminating organisms like Gram-positive bacteria and yeast.

A

Thayer-Martin Agar

19
Q
  • Isolates: Selective for Pseudomonas aeruginosa, which produces characteristic green or blue-green colonies due to pyocyanin production.
A

Cetrimide Agar

20
Q
  • Isolates: Selective for Mycobacterium species, especially Mycobacterium tuberculosis.
A

Lowenstein-Jensen Medium

21
Q

It contains malachite green to inhibit the growth of contaminants.

A

Lowenstein-Jensen Medium:

22
Q
  • Isolates: Selective for fungi, including yeasts and molds. The acidic pH of the medium inhibits bacterial growth, favoring fungal growth.
A

Sabouraud Dextrose Agar (SDA)

23
Q
  • Isolates: Selective for Gram-negative bacteria. It differentiates between lactose fermenters like E. coli (which produces metallic green colonies) and non-lactose fermenters (which produce colorless or pink colonies)
A

Eosin Methylene Blue (EMB) Agar

24
Q

are those that require specific nutrients or environmental conditions to grow, often needing enriched or enrichment media.

A

Fastidious bacteria

25
Q

Fastidious bacteria

A

Neisseria gonorrhoeae and Neisseria meningitidis

Haemophilus influenzae

Streptococcus pneumoniae

Legionella pneumophila

Mycobacterium tuberculosis

26
Q
  • Media Required: Thayer-Martin agar or Chocolate agar.
  • Reason: These bacteria require enriched media with added nutrients like hemoglobin, vitamins, and coenzymes to grow.
A

Neisseria gonorrhoeae and Neisseria meningitidis

27
Q
  • Media Required: Chocolate agar or Levinthal agar.
  • Reason: Requires factors X (hemin) and V (NAD) that are present in lysed red blood cells found in chocolate agar.
A

Haemophilus influenzae

28
Q
  • Media Required: Blood agar with added carbon dioxide.
  • Reason: This organism is fastidious and grows better in an environment with enriched nutrients and elevated CO2.
A

Streptococcus pneumoniae

29
Q
  • Media Required: Buffered Charcoal Yeast Extract (BCYE) agar.
  • Reason: Requires L-cysteine and iron salts, which are provided by BCYE agar.
A

Legionella pneumophila

30
Q
  • Media Required: Lowenstein-Jensen medium or Middlebrook agar.
  • Reason: Requires enriched media with malachite green to inhibit contaminants and provide essential nutrients for growth
A

Mycobacterium tuberculosis

31
Q

Enrichment and isolation of Salmonella spp.

Peptone-base broth; sodium selenite toxic for
most Enterobacterales

A

Selenite broth

32
Q

Contains crystal violet, colistin, and trimethoprim-sulfamethoxazole in 5% sheep blood agar base

Selective for Streptococcus pyogenes and Streptococcus agalactiae

A

Streptococcal selective agar (SSA)

33
Q

Selective for N. gonorrhoeae and N. meningitidis.
Supports the growth of Francisella and Brucella spp.

Blood agar base enriched with hemoglobin and supplement B; contaminating organisms inhibited by colistin, nystatin, vancomycin, and trimethoprim

A

Thayer Martin

34
Q

Supports growth of anaerobes, aerobes, micro-aerophilic, and fastidious microorganisms

A

Thioglycollate broth

35
Q

Selective and differential for Vibrio cholerae and Vibrio parahaemolyticus

A

Thiosulfate citrate-bile salts (TCBS) agar

36
Q

Basal back-up broth or enrichment broth used for subculturing various bacteria from primary agar plates

All-purpose basal broth that can support the growth of many nonfastidious organisms or when supplemented with additional nutrients, it is used to cultivate fastidious microorganisms.

A

Trypticase soy broth
(TSB)

37
Q

Cultivation of fastidious microorganisms such as Haemophilus spp., Brucella spp., and pathogenic Neisseria spp.

A

Chocolate agar

38
Q

Isolation of Corynebacterium diphtheriae

A

Cystine-tellurite blood
agar

39
Q

Isolation and differentiation of lactose-fermenting and non-lactose-fermenting enteric bacilli

Peptone base containing lactose; eosin Y and methylene blue as indicators

A

Eosin methylene blue
(EMB) agar (Levine)

40
Q

Selective (enrichment) liguid medium for enteric pathogens Salmonella and Shigella spp.

Peptone-base broth with glucose and mannitol;
sodium citrate and sodium deoxycholate act as inhibitory agents

A

Gram-negative broth
(GN)

41
Q

Differential, selective medium for the isolation and differentiation of Salmonella and Shigella spp. from other GN enteric bacilli

Peptone-base agar with bile salts, lactose, sucrose, salicin, and ferric ammonium citrate; indicators include bromothymol blue and acid fuchsin

A

Hektoen enteric (HE)
agar

42
Q

Isolation and differentiation of lactose fermenting and non-lactose-fermenting enteric bacilli

Peptone base with lactose; gram-positive organisms inhibited by crystal violet and bile salts;
neutral red as indicator

A

MacConkey agar

43
Q

Inverted Umbrella/Christmas Tree appearance of _______on SIM.

A

Listeria monocytogenes

44
Q

Test Tube Brush appearance of _______on SIM.

A

Erysipelothrix rhusiopathiae