Culture Media by Morphological Classification

Morphological Class

Protozoa

Culture Media

1 Sula’s Medium A liquid medium containing glycerol, asparagine, and a variety of salts. The growth of M. tuberculosis results in turbidity.
2 Middlebrook 7H9 Broth This is a liquid medium that contains glycerol and Tween 80, which prevent clumping of mycobacteria. The growth of M. tuberculosis results in turbidity.
3 Dubos’ Medium A liquid medium that contains a mixture of salts, fatty acids, and polysorbate. When M. tuberculosis grows in this medium, it causes the medium to become turbid.
4 Loeffler Medium A serum-based medium. M. tuberculosis colonies on Loeffler medium are small, dry, wrinkled, and off-white to yellow.
5 Dorset Medium An egg-based medium. M. tuberculosis colonies appear similar to those on Petragnini Medium: small, round, buff-colored, and taking 3-4 weeks to develop.
6 Brilliant Green Agar (BGA) A selective medium that is used to isolate Salmonella species, but E. coli can grow on it, albeit not as well.
7 Sorbitol-MacConkey agar A variant of MacConkey agar, used in detecting E. coli O157:H7, which does not ferment sorbitol, unlike most strains of E. coli.
8 Urea Agar/Broth E. coli is typically urease negative, so no color change would be expected in this medium.
9 Simmons Citrate Agar Used for citrate utilization testing. E. coli usually can't utilize citrate as a sole carbon source, so no growth or color change would be expected.
10 Tryptic Soy Agar (TSA) A general purpose medium. E. coli colonies are medium to large, with a shiny moist appearance.
11 m-ENDO Agar E. coli colonies appear as green with a metallic sheen, indicating lactose fermentation.
12 Nutrient Agar (NA) A non-selective medium. E. coli colonies are usually large, circular, grayish-white, moist, and smooth.
13 CHROMagar Candida This differential medium allows for the isolation and identification of Candida species based on colony color. Candida albicans usually forms green colonies on this medium.
14 Sabouraud Dextrose Agar (SDA) It is composed of peptone, dextrose (glucose), and agar. The high dextrose concentration promotes fungal growth, while the acidic pH inhibits bacterial growth.

Mycobacteria

Culture Media

1 Baird-Parker Agar (BPA) his is a selective medium for the isolation of Staphylococcus species. It has lithium chloride and glycine to inhibit the growth of Gram-negative bacteria and most Gram-positive bacteria except Staphylococcus. Egg yolk emulsion is added to detect lecithinase production and tellurite reduction. S. aureus colonies on BPA are black due to reduction of tellurite, and they exhibit a clear zone due to lecithinase activity on egg yolk.
2 Phenol Red Mannitol Broth This is a differential medium, used to determine an organism's ability to ferment mannitol. S. aureus, which can ferment mannitol, will change the medium from red to yellow due to acid production.
3 BACTEC This is not a traditional medium but a system for detecting the growth of M. tuberculosis by monitoring the release of C14O2 from C14 palmitic acid, which the bacteria metabolize. An increase in radioactive counts in the BACTEC instrument indicates the growth of bacteria.
4 Middlebrook 7H9 Broth This is a liquid medium that contains glycerol and Tween 80, which prevent clumping of mycobacteria. The growth of M. tuberculosis results in turbidity.
5 Loeffler Medium A serum-based medium. M. tuberculosis colonies on Loeffler medium are small, dry, wrinkled, and off-white to yellow.
6 Tarshis Medium A blood-based medium that can promote the growth of M. tuberculosis. The colonies appear similar to those on the LJ Medium.
7 Nickerson’s Medium or Bismuth Sulfite Glucose Glycine Yeast (BSGG) This medium is used to stimulate the production of germ tubes, a characteristic of Candida albicans.
8 CHROMagar Candida This differential medium allows for the isolation and identification of Candida species based on colony color. Candida albicans usually forms green colonies on this medium.
9 Sabouraud Dextrose Agar (SDA) It is composed of peptone, dextrose (glucose), and agar. The high dextrose concentration promotes fungal growth, while the acidic pH inhibits bacterial growth.
10 Brain-Heart Infusion (BHI) Broth or Agar This is a nutrient-rich medium that supports the growth of a variety of fastidious organisms, including E. faecalis. The typical phenotype of E. faecalis on BHI is small, round, and white colonies.

Fungi

Culture Media

1 Blood Agar (BA) This is a nutrient-rich, differential medium that supports the growth of many organisms. S. aureus forms colonies that are round, smooth, and golden-yellow. This bacterium typically demonstrates β-hemolysis, which is complete lysis of red blood cells, resulting in a clear zone around the colonies. This hemolysis is due to the production of hemolysins by S. aureus.
2 Triple Sugar Iron (TSI) Agar E. coli typically produces an acid butt, acid slant, and gas, with no H2S production, indicating it ferments lactose, sucrose, and glucose.
3 Simmons Citrate Agar Used for citrate utilization testing. E. coli usually can't utilize citrate as a sole carbon source, so no growth or color change would be expected.
4 Eosin Methylene Blue (EMB) Agar A selective and differential medium where E. coli forms distinctive metallic green sheen colonies due to vigorous lactose fermentation.
5 Potato Dextrose Agar (PDA) Potato Dextrose Agar (PDA) consists of a nutrient-rich substrate, made from dehydrated Potato Infusion and Dextrose, ideal for robust mycological propagation. Agar provides the solidifying medium. Acidification, typically using sterile tartaric acid, adjusts the pH to 3.5 +/- 0.1 to create a more selective environment by inhibiting bacterial proliferation. Additionally, Chloramphenicol is incorporated as an antimicrobial agent to further suppress bacterial contamination, thereby facilitating the selective isolation of fungi.
6 Sabouraud Dextrose Agar (SDA) It is composed of peptone, dextrose (glucose), and agar. The high dextrose concentration promotes fungal growth, while the acidic pH inhibits bacterial growth.
7 Blood Agar A differential medium used to identify bacteria based on their hemolytic properties. E. faecalis typically shows gamma-hemolysis on this medium, i.e., no hemolysis or change in the color of the medium.
8 Tryptic Soy Broth or Agar (TSB/TSA) A general-purpose medium that supports the growth of a broad spectrum of bacteria. E. faecalis on TSA will typically form small, round, and white colonies, indicating a positive growth.

Bacilli

Culture Media

1 Blood Agar (BA) This is a nutrient-rich, differential medium that supports the growth of many organisms. S. aureus forms colonies that are round, smooth, and golden-yellow. This bacterium typically demonstrates β-hemolysis, which is complete lysis of red blood cells, resulting in a clear zone around the colonies. This hemolysis is due to the production of hemolysins by S. aureus.
2 Middlebrook 7H9 Broth This is a liquid medium that contains glycerol and Tween 80, which prevent clumping of mycobacteria. The growth of M. tuberculosis results in turbidity.
3 Dubos’ Medium A liquid medium that contains a mixture of salts, fatty acids, and polysorbate. When M. tuberculosis grows in this medium, it causes the medium to become turbid.
4 Lysine Iron Agar (LIA) Used to determine the ability of an organism to decarboxylate or deaminate lysine and to form hydrogen sulfide. E. coli is typically lysine decarboxylase positive and H2S negative, so you would see a reaction of red/purple slant and purple/red butt with no black precipitate.
5 Simmons Citrate Agar Used for citrate utilization testing. E. coli usually can't utilize citrate as a sole carbon source, so no growth or color change would be expected.
6 Mueller Hinton Agar (MHA) Typically used for antibiotic susceptibility testing. E. coli colonies appear pale straw colored.
7 Nutrient Agar (NA) A non-selective medium. E. coli colonies are usually large, circular, grayish-white, moist, and smooth.
8 Potato Dextrose Agar (PDA) Potato Dextrose Agar (PDA) consists of a nutrient-rich substrate, made from dehydrated Potato Infusion and Dextrose, ideal for robust mycological propagation. Agar provides the solidifying medium. Acidification, typically using sterile tartaric acid, adjusts the pH to 3.5 +/- 0.1 to create a more selective environment by inhibiting bacterial proliferation. Additionally, Chloramphenicol is incorporated as an antimicrobial agent to further suppress bacterial contamination, thereby facilitating the selective isolation of fungi.
9 Sabouraud Dextrose Agar (SDA) It is composed of peptone, dextrose (glucose), and agar. The high dextrose concentration promotes fungal growth, while the acidic pH inhibits bacterial growth.
10 Azide Dextrose Broth A selective medium inhibiting Gram-negative bacteria, used for the isolation of streptococci and staphylococci from mixed samples. E. faecalis will show a positive growth resulting in a turbid appearance of the broth.
11 Tryptic Soy Broth or Agar (TSB/TSA) A general-purpose medium that supports the growth of a broad spectrum of bacteria. E. faecalis on TSA will typically form small, round, and white colonies, indicating a positive growth.

Cocci

Culture Media

1 BACTEC This is not a traditional medium but a system for detecting the growth of M. tuberculosis by monitoring the release of C14O2 from C14 palmitic acid, which the bacteria metabolize. An increase in radioactive counts in the BACTEC instrument indicates the growth of bacteria.
2 Sula’s Medium A liquid medium containing glycerol, asparagine, and a variety of salts. The growth of M. tuberculosis results in turbidity.
3 Proskauer and Beck’s Medium A liquid medium. The growth of M. tuberculosis causes turbidity.
4 Middlebrook 7H9 Broth This is a liquid medium that contains glycerol and Tween 80, which prevent clumping of mycobacteria. The growth of M. tuberculosis results in turbidity.
5 Dubos’ Medium A liquid medium that contains a mixture of salts, fatty acids, and polysorbate. When M. tuberculosis grows in this medium, it causes the medium to become turbid.
6 Pawlowsky Medium A potato-based medium. Growth of M. tuberculosis may be similar to that seen on the LJ Medium.
7 Loeffler Medium A serum-based medium. M. tuberculosis colonies on Loeffler medium are small, dry, wrinkled, and off-white to yellow.
8 Middlebrook 7H10 Agar A selective medium that contains oleic acid, albumin, dextrose, and catalase. The colonies of M. tuberculosis appear small, rough, and buff to white-colored, taking less time to appear compared to egg-based media.
9 Petragnini Medium An egg-based medium enriched with additional nutrients to promote the growth of Mycobacterium tuberculosis. Colonies of M. tuberculosis are small, round, buff-colored, and typically take 3-4 weeks to appear.
10 Lowenstein-Jensen (LJ) Medium An egg-based medium that uses malachite green to suppress the growth of other bacteria and glycerol to stimulate the growth of Mycobacterium tuberculosis. The colonies of M. tuberculosis on LJ are non-pigmented, dry, rough, raised, irregular with a wrinkled surface, initially creamy-white, turning yellowish or buff-colored on further incubation.
11 Liquid Media (such as Nutrient Broth) E. coli exhibits homogenous turbid growth within 12-18 hours. After prolonged incubation, pellicles may form on the surface of the media.
12 Sorbitol-MacConkey agar A variant of MacConkey agar, used in detecting E. coli O157:H7, which does not ferment sorbitol, unlike most strains of E. coli.
13 Urea Agar/Broth E. coli is typically urease negative, so no color change would be expected in this medium.
14 Violet Red Bile Agar (VRBA) E. coli colonies are red (pink to red) and may show bluish fluorescence under UV light.
15 Eosin Methylene Blue (EMB) Agar A selective and differential medium where E. coli forms distinctive metallic green sheen colonies due to vigorous lactose fermentation.
16 Nickerson’s Medium or Bismuth Sulfite Glucose Glycine Yeast (BSGG) This medium is used to stimulate the production of germ tubes, a characteristic of Candida albicans.
17 Sabouraud Dextrose Agar (SDA) It is composed of peptone, dextrose (glucose), and agar. The high dextrose concentration promotes fungal growth, while the acidic pH inhibits bacterial growth.
18 Nutrient Agar It is a general-purpose medium. However, E. faecalis grows poorly on nutrient agar, which means it does not proliferate as well on this medium compared to the others listed, indicating a negative or poor growth.
19 Tryptic Soy Broth or Agar (TSB/TSA) A general-purpose medium that supports the growth of a broad spectrum of bacteria. E. faecalis on TSA will typically form small, round, and white colonies, indicating a positive growth.

Spirillum

Culture Media

1 Sauton’s Medium A liquid medium that lacks detergents, which helps in the formation of corded colonies. When M. tuberculosis grows in this medium, it results in turbidity.
2 BACTEC This is not a traditional medium but a system for detecting the growth of M. tuberculosis by monitoring the release of C14O2 from C14 palmitic acid, which the bacteria metabolize. An increase in radioactive counts in the BACTEC instrument indicates the growth of bacteria.
3 Proskauer and Beck’s Medium A liquid medium. The growth of M. tuberculosis causes turbidity.
4 Middlebrook 7H9 Broth This is a liquid medium that contains glycerol and Tween 80, which prevent clumping of mycobacteria. The growth of M. tuberculosis results in turbidity.
5 Dubos’ Medium A liquid medium that contains a mixture of salts, fatty acids, and polysorbate. When M. tuberculosis grows in this medium, it causes the medium to become turbid.
6 Loeffler Medium A serum-based medium. M. tuberculosis colonies on Loeffler medium are small, dry, wrinkled, and off-white to yellow.
7 Middlebrook 7H10 Agar A selective medium that contains oleic acid, albumin, dextrose, and catalase. The colonies of M. tuberculosis appear small, rough, and buff to white-colored, taking less time to appear compared to egg-based media.
8 Lowenstein-Jensen (LJ) Medium An egg-based medium that uses malachite green to suppress the growth of other bacteria and glycerol to stimulate the growth of Mycobacterium tuberculosis. The colonies of M. tuberculosis on LJ are non-pigmented, dry, rough, raised, irregular with a wrinkled surface, initially creamy-white, turning yellowish or buff-colored on further incubation.
9 Lysine Iron Agar (LIA) Used to determine the ability of an organism to decarboxylate or deaminate lysine and to form hydrogen sulfide. E. coli is typically lysine decarboxylase positive and H2S negative, so you would see a reaction of red/purple slant and purple/red butt with no black precipitate.
10 Sorbitol-MacConkey agar A variant of MacConkey agar, used in detecting E. coli O157:H7, which does not ferment sorbitol, unlike most strains of E. coli.
11 Urea Agar/Broth E. coli is typically urease negative, so no color change would be expected in this medium.
12 Simmons Citrate Agar Used for citrate utilization testing. E. coli usually can't utilize citrate as a sole carbon source, so no growth or color change would be expected.
13 Tryptic Soy Agar (TSA) A general purpose medium. E. coli colonies are medium to large, with a shiny moist appearance.
14 Mueller Hinton Agar (MHA) Typically used for antibiotic susceptibility testing. E. coli colonies appear pale straw colored.
15 Nutrient Agar (NA) A non-selective medium. E. coli colonies are usually large, circular, grayish-white, moist, and smooth.
16 Nickerson’s Medium or Bismuth Sulfite Glucose Glycine Yeast (BSGG) This medium is used to stimulate the production of germ tubes, a characteristic of Candida albicans.
17 Sabouraud Dextrose Agar (SDA) It is composed of peptone, dextrose (glucose), and agar. The high dextrose concentration promotes fungal growth, while the acidic pH inhibits bacterial growth.
18 Azide Dextrose Broth A selective medium inhibiting Gram-negative bacteria, used for the isolation of streptococci and staphylococci from mixed samples. E. faecalis will show a positive growth resulting in a turbid appearance of the broth.
19 Bile Esculin Agar (BEA) A selective and differential medium that differentiates group D Streptococci and Enterococci based on the ability to hydrolyze esculin in the presence of bile. E. faecalis hydrolyzes esculin, leading to the formation of a dark brown or black precipita
20 Tryptic Soy Broth or Agar (TSB/TSA) A general-purpose medium that supports the growth of a broad spectrum of bacteria. E. faecalis on TSA will typically form small, round, and white colonies, indicating a positive growth.

Spirochetes

Culture Media

1 Phenol Red Mannitol Broth This is a differential medium, used to determine an organism's ability to ferment mannitol. S. aureus, which can ferment mannitol, will change the medium from red to yellow due to acid production.
2 BACTEC This is not a traditional medium but a system for detecting the growth of M. tuberculosis by monitoring the release of C14O2 from C14 palmitic acid, which the bacteria metabolize. An increase in radioactive counts in the BACTEC instrument indicates the growth of bacteria.
3 Proskauer and Beck’s Medium A liquid medium. The growth of M. tuberculosis causes turbidity.
4 Middlebrook 7H9 Broth This is a liquid medium that contains glycerol and Tween 80, which prevent clumping of mycobacteria. The growth of M. tuberculosis results in turbidity.
5 Pawlowsky Medium A potato-based medium. Growth of M. tuberculosis may be similar to that seen on the LJ Medium.
6 Loeffler Medium A serum-based medium. M. tuberculosis colonies on Loeffler medium are small, dry, wrinkled, and off-white to yellow.
7 Middlebrook 7H10 Agar A selective medium that contains oleic acid, albumin, dextrose, and catalase. The colonies of M. tuberculosis appear small, rough, and buff to white-colored, taking less time to appear compared to egg-based media.
8 Petragnini Medium An egg-based medium enriched with additional nutrients to promote the growth of Mycobacterium tuberculosis. Colonies of M. tuberculosis are small, round, buff-colored, and typically take 3-4 weeks to appear.
9 Lowenstein-Jensen (LJ) Medium An egg-based medium that uses malachite green to suppress the growth of other bacteria and glycerol to stimulate the growth of Mycobacterium tuberculosis. The colonies of M. tuberculosis on LJ are non-pigmented, dry, rough, raised, irregular with a wrinkled surface, initially creamy-white, turning yellowish or buff-colored on further incubation.
10 Brilliant Green Agar (BGA) A selective medium that is used to isolate Salmonella species, but E. coli can grow on it, albeit not as well.
11 Urea Agar/Broth E. coli is typically urease negative, so no color change would be expected in this medium.
12 Triple Sugar Iron (TSI) Agar E. coli typically produces an acid butt, acid slant, and gas, with no H2S production, indicating it ferments lactose, sucrose, and glucose.
13 Violet Red Bile Agar (VRBA) E. coli colonies are red (pink to red) and may show bluish fluorescence under UV light.
14 Nickerson’s Medium or Bismuth Sulfite Glucose Glycine Yeast (BSGG) This medium is used to stimulate the production of germ tubes, a characteristic of Candida albicans.
15 RPMI 1640 Medium It is a rich medium that contains inorganic salts, glucose, amino acids, vitamins, and other nutrients that promote the growth of yeast cells.
16 Nutrient Agar It is a general-purpose medium. However, E. faecalis grows poorly on nutrient agar, which means it does not proliferate as well on this medium compared to the others listed, indicating a negative or poor growth.
17 Bile Esculin Agar (BEA) A selective and differential medium that differentiates group D Streptococci and Enterococci based on the ability to hydrolyze esculin in the presence of bile. E. faecalis hydrolyzes esculin, leading to the formation of a dark brown or black precipita