Culture Media by Morphological Classification

Morphological Class

Protozoa

Culture Media

1 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.
2 Tryptic Soy Agar (TSA) A general purpose medium. E. coli colonies are medium to large, with a shiny moist appearance.
3 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.

Mycobacteria

Culture Media

1 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.
2 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.

Fungi

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 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.
3 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.
4 Cystine Lactose Electrolyte-Deficient (CLED) Agar E. coli will give lactose-positive yellow colonies.
5 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.
6 Todd-Hewitt Broth A liquid enrichment medium used for the cultivation of fastidious organisms such as streptococci and enterococci. E. faecalis will lead to a turbid broth due to microbial 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 Sula’s Medium A liquid medium containing glycerol, asparagine, and a variety of salts. The growth of M. tuberculosis results in turbidity.
3 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.
4 Tarshis Medium A blood-based medium that can promote the growth of M. tuberculosis. The colonies appear similar to those on the LJ Medium.
5 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.
6 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.
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 Cornmeal Agar with Tween 80 It is used for the identification of Candida species by promoting the formation of chlamydospores, which is a characteristic of Candida albicans.
9 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.
10 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.
11 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.
12 Todd-Hewitt Broth A liquid enrichment medium used for the cultivation of fastidious organisms such as streptococci and enterococci. E. faecalis will lead to a turbid broth due to microbial growth.
13 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

Cocci

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 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.
3 Sula’s Medium A liquid medium containing glycerol, asparagine, and a variety of salts. The growth of M. tuberculosis results in turbidity.
4 Tarshis Medium A blood-based medium that can promote the growth of M. tuberculosis. The colonies appear similar to those on the LJ Medium.
5 Middlebrook 7H11 Agar This is a nutrient-rich medium similar to 7H10 but includes additional pyruvate for energy source, promoting more luxurious growth. The colonies of M. tuberculosis appear small, slightly domed, and rough with a butyrous consistency.
6 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.
7 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.
8 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.
9 Urea Agar/Broth E. coli is typically urease negative, so no color change would be expected in this medium.
10 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.
11 Cystine Lactose Electrolyte-Deficient (CLED) Agar E. coli will give lactose-positive yellow colonies.
12 MacConkey Agar (MAC) This selective and differential medium distinguishes lactose fermenters from non-fermenters. E. coli colonies are circular, moist, smooth, and pink.
13 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.
14 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.
15 Todd-Hewitt Broth A liquid enrichment medium used for the cultivation of fastidious organisms such as streptococci and enterococci. E. faecalis will lead to a turbid broth due to microbial growth.

Spirillum

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 Sula’s Medium A liquid medium containing glycerol, asparagine, and a variety of salts. The growth of M. tuberculosis results in turbidity.
3 Tarshis Medium A blood-based medium that can promote the growth of M. tuberculosis. The colonies appear similar to those on the LJ Medium.
4 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.
5 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.
6 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.
7 Cystine Lactose Electrolyte-Deficient (CLED) Agar E. coli will give lactose-positive yellow colonies.
8 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.
9 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.
10 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.
11 Todd-Hewitt Broth A liquid enrichment medium used for the cultivation of fastidious organisms such as streptococci and enterococci. E. faecalis will lead to a turbid broth due to microbial growth.
12 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

Spirochetes

Culture Media

1 Sf1Ep medium Culturing Treponema pallidum, the bacteria that causes syphilis, in vitro is a challenge. T. pallidum is not routinely cultured in the laboratory for diagnostic purposes, in part because it cannot be grown on artificial media. However, a breakthrough in culturing T. pallidum was reported in 2018 when researchers managed to grow the bacterium in a rabbit epithelial cell line (Sf1Ep) using a medium called 'Sf1Ep medium'. It's not used for routine diagnostic purposes, but for research only. The diagnosis involves direct microscopic examination, serologic tests, molecular tests and histopathology.
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 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.
4 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.
5 Sula’s Medium A liquid medium containing glycerol, asparagine, and a variety of salts. The growth of M. tuberculosis results in turbidity.
6 Loeffler Medium A serum-based medium. M. tuberculosis colonies on Loeffler medium are small, dry, wrinkled, and off-white to yellow.
7 Middlebrook 7H11 Agar This is a nutrient-rich medium similar to 7H10 but includes additional pyruvate for energy source, promoting more luxurious growth. The colonies of M. tuberculosis appear small, slightly domed, and rough with a butyrous consistency.
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 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.
10 Urea Agar/Broth E. coli is typically urease negative, so no color change would be expected in this medium.
11 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.
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 Cystine Lactose Electrolyte-Deficient (CLED) Agar E. coli will give lactose-positive yellow colonies.
14 Eosin Methylene Blue (EMB) Agar A selective and differential medium where E. coli forms distinctive metallic green sheen colonies due to vigorous lactose fermentation.
15 MacConkey Agar (MAC) This selective and differential medium distinguishes lactose fermenters from non-fermenters. E. coli colonies are circular, moist, smooth, and pink.
16 Blood Agar (BA) E. coli colonies on this differential medium are large, circular, gray, moist, and can show β-hemolysis.
17 Nutrient Agar (NA) A non-selective medium. E. coli colonies are usually large, circular, grayish-white, moist, and smooth.
18 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.
19 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.
20 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.
21 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.
22 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.
23 Todd-Hewitt Broth A liquid enrichment medium used for the cultivation of fastidious organisms such as streptococci and enterococci. E. faecalis will lead to a turbid broth due to microbial growth.
24 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