1Mannitol Salt Agar (MSA), or Chapman AgarThis is a selective and differential medium. The high concentration of NaCl (~7.5%) selects for halophiles, organisms that can tolerate high salt concentrations, thereby favouring the growth of Staphylococcus species. Mannitol is the differential component: S. aureus ferments mannitol, lowering the pH of the medium, which results in a color change of the pH indicator from red to yellow. Thus, growth of S. aureus is indicated by yellow colonies.
2Lowenstein-Jensen (LJ) MediumAn 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.
1Tryptic Soy Agar (TSA)A general purpose medium. E. coli colonies are medium to large, with a shiny moist appearance.
2RPMI 1640 MediumIt is a rich medium that contains inorganic salts, glucose, amino acids, vitamins, and other nutrients that promote the growth of yeast cells.
3Potato 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.
4Sabouraud 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.
1Blood 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.
2Dubos’ MediumA 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.
3Tarshis MediumA blood-based medium that can promote the growth of M. tuberculosis. The colonies appear similar to those on the LJ Medium.
4m-ENDO AgarE. coli colonies appear as green with a metallic sheen, indicating lactose fermentation.
1Tarshis MediumA blood-based medium that can promote the growth of M. tuberculosis. The colonies appear similar to those on the LJ Medium.
2Liquid 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.
3Urea Agar/BrothE. coli is typically urease negative, so no color change would be expected in this medium.
4Triple Sugar Iron (TSI) AgarE. coli typically produces an acid butt, acid slant, and gas, with no H2S production, indicating it ferments lactose, sucrose, and glucose.
5Cornmeal Agar with Tween 80It is used for the identification of Candida species by promoting the formation of chlamydospores, which is a characteristic of Candida albicans.
6Sabouraud 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.
1Phenol Red Mannitol BrothThis 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.
2Blood 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.
3Sula’s MediumA liquid medium containing glycerol, asparagine, and a variety of salts. The growth of M. tuberculosis results in turbidity.
4Middlebrook 7H11 AgarThis 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.
5MacConkey Agar (MAC)This selective and differential medium distinguishes lactose fermenters from non-fermenters. E. coli colonies are circular, moist, smooth, and pink.
6Nickerson’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.
7Bile 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
1Dubos’ MediumA 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.
2Tarshis MediumA blood-based medium that can promote the growth of M. tuberculosis. The colonies appear similar to those on the LJ Medium.
3Brilliant Green Agar (BGA)A selective medium that is used to isolate Salmonella species, but E. coli can grow on it, albeit not as well.
4Nickerson’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.
5Blood AgarA 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.
1Mannitol Salt Agar (MSA), or Chapman AgarThis is a selective and differential medium. The high concentration of NaCl (~7.5%) selects for halophiles, organisms that can tolerate high salt concentrations, thereby favouring the growth of Staphylococcus species. Mannitol is the differential component: S. aureus ferments mannitol, lowering the pH of the medium, which results in a color change of the pH indicator from red to yellow. Thus, growth of S. aureus is indicated by yellow colonies.
2Pawlowsky MediumA potato-based medium. Growth of M. tuberculosis may be similar to that seen on the LJ Medium.
3Loeffler MediumA serum-based medium. M. tuberculosis colonies on Loeffler medium are small, dry, wrinkled, and off-white to yellow.
4Petragnini MediumAn 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.
5Brilliant Green Agar (BGA)A selective medium that is used to isolate Salmonella species, but E. coli can grow on it, albeit not as well.
6Cystine Lactose Electrolyte-Deficient (CLED) AgarE. coli will give lactose-positive yellow colonies.
7Violet Red Bile Agar (VRBA)E. coli colonies are red (pink to red) and may show bluish fluorescence under UV light.
8Mueller Hinton Agar (MHA)Typically used for antibiotic susceptibility testing. E. coli colonies appear pale straw colored.
9Nickerson’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.
10Blood AgarA 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.
11Enterococcosel AgarA selective and differential medium that inhibits the growth of Gram-negative bacteria and distinguishes enterococci based on their ability to grow in the presence of bile and hydrolyze esculin. E. faecalis will form small, black colonies on this medium due to esculin hydrolysis.
12Brain-Heart Infusion (BHI) Broth or AgarThis 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.