Nutrient Agar- Principle, Composition, Preparation, Results, Uses

Nutrient Agar

What is Nutrient Agar? Nutrient Agar is a basic culture medium commonly used for the culture of non-fastidious microorganisms, and for quality control and checking purity prior to biochemical or serological testing. Nutrient media can also be used for the cultivation of fastidious microorganism by enriching the medium with serum or blood Nutrient Agar is an ideal medium for the demonstration and teaching purposes as it allows more prolonged survival of cultures at ambient temperature without the risk of overgrowth … Read more

Selenite F Broth- Composition, Principle, Preparation, Results, Uses

Result Interpretation on Selenite F Broth

Selenite Broth was devised by Leifson, who demonstrated that selenite was inhibitory for coliforms and certain other microbial species, such as fecal streptococci, present in fecal specimens and, thus, was beneficial in the recovery of Salmonella species. Selenite-F Broth is used as an enrichment medium buffered with Lactose Peptone Broth to which Sodium Biselenite is added as the selective agent for the isolation of Salmonella from feces, urine, water, foods, and other materials of sanitary importance. Composition of Selenite F … Read more

Triple Sugar Iron (TSI) Agar- Composition, Principle, Preparation, Results, Uses

Triple Sugar Iron (TSI) Agar

Most bacteria have the ability to ferment carbohydrates, particularly sugars. Among them, each bacterium can ferment only some of the sugars, while it cannot ferment the others. Thus, the sugars, which a bacterium can ferment, and the sugars, which it cannot is the characteristic of the bacteria and thus an important criterion for its identification. The Triple Sugar Iron (TSI) agar is a culture medium named for its ability to test a microorganism’s ability to ferment sugars and to produce hydrogen sulfide. Composition of … Read more

Charcoal Selective Medium- Composition, Principle, Preparation, Results, Uses

Result Interpretation on Charcoal Selective Medium

In 1984, Bolton et al. stated charcoal might efficiently substitute blood in a culture medium for isolating Campylobacter spp. Endtz et al. later confirmed there is a higher isolation rate for Campylobacter while using the charcoal selective medium. Composition of Charcoal Selective Medium Ingredients Gm/Liter Beef extract 10.0g Gelatin Peptone 10.0g Sodium Chloride 5.0g Casein Peptone 3.0g Charcoal 4.0g Sodium desoxycholate 1.0g Ferrous sulfate 0.25g Sodium Pyruvate 0.25g Cycloheximide 100.0mg Cefoperazone 32.0mg Hematin 32.0mg Vancomycin 20.0mg Agar 12.0g pH 7.4± … Read more

Modified Thayer Martin Agar- Composition, Principle, Preparation, Results, Uses

Modified Thayer Martin Agar

Thayer and Martin reported an improvement of the Chocolate Agar formulation that contained antimicrobics vancomycin, colistin and nystatin have been added to minimize overgrowth by contaminants, suppress the growth of saprophytic Neisseria sp., and enhance the growth of pathogenic Neisseria. Martin and Lester later added antibiotic trimethoprim to make the medium further selective and shown to be of value in the suppression of Proteus spp. Trimethoprim lactate refrains Proteus swarming. The resulting medium is called Modified Thayer Martin. It is a selective … Read more

Starch Casein Agar (SCA)- Composition, Principle, Preparation, Results

Starch casein agar

What is Starch casein agar (SCA)? Starch casein agar is a nutrient medium for the growth and cultivation of saccharolytic marine bacteria. Starch casein agar, as the name suggests, has starch has the primary source of carbohydrates. This media is primarily used for the isolation and cultivation of actinomycetes for various sources like soil and marine sediments. Starch Casein agar consists of seawater which contains various nutrients, vitamins, and sea salt that support the growth of marine inhabitants, and actinomycetes … Read more

Mannitol Salt Agar (MSA)- Composition, Principle, Preparation, Results, Uses

Results on Mannitol Salt Agar (MSA)

Mannitol Salt Agar (MSA) is used as a selective and differential medium for the isolation and identification of Staphylococcus aureus from clinical and non-clinical specimens. It is recommended for the detection and enumeration of coagulase-positive Staphylococci in milk, food, and other specimens and encourages the growth of a group of certain bacteria while inhibiting the growth of others. Principle of Mannitol Salt Agar (MSA) Mannitol Salt Agar contains beef extract and proteose peptone, which makes it very nutritious as they provide essential growth … Read more

Blood Agar- Composition, Principle, Preparation, Uses and Hemolysis

Blood Agar- Composition, Principle, Preparation and Uses

What is Blood Agar? Blood Agar is an enriched medium provided with multiple nutrients that generally comes as a basal media for the preparation of blood agar by supplementation with blood. Blood Agar comes as a basal medium that can be used as it is as a general growth medium. The basal medium can be either Columbia Agar or Tryptic Soy Agar. Blood agar is an excellent medium for the cultivation of fastidious bacteria that require particular nutrients and don’t … Read more

Amies Transport Medium- Composition, Principle, Preparation, Results, Uses

Amies Transport Medium

Amies Transport Medium is an improved transport medium, containing charcoal to prolong the viability of pathogenic organisms. It is a semisolid media recommended for use in qualitative procedures for the transport of clinical swab specimens to the laboratory. It is the modified Stuart’s Transport Medium produced by replacing glycerophosphate with an inorganic phosphate buffer and adding charcoal to the medium. This modified medium gave a higher percentage of positive results than the transport medium of Stuart. Composition of Amies Transport Medium … Read more

Simmons Citrate Agar- Composition, Principle, Preparation, Results, Uses

Result Interpretation on Simmons Citrate Agar

Simmons citrate agar is a selective and differential medium that tests for an organism’s ability to use citrate as a sole carbon source and ammonium ions as the sole nitrogen source. It is used for differentiating gram-negative bacteria on the basis of citrate utilization. It is useful for selecting organisms that use citrate as their main carbon and energy source. Initially, the citrate medium was developed by Koser containing ammonium salt as the only nitrogen source and citrate as the only carbon … Read more