Online microbiology and biology related notes by SAGAR ARYAL
Tryptic Soy Agar Tryptic Soy Agar is used as a general growth medium for the isolation and cultivation of microorganisms. They are general-purpose, non-selective media providing enough nutrients to allow for a wide variety of microorganisms to grow. This medium is also recommended for use in the cultivation, storage, maintenance and transportation of pure cultures … Read moreTryptic Soy Agar
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 … Read moreTriple Sugar Iron (TSI) Agar
Violet Red Bile Agar (VRBA) Coliforms refer to all aerobic and facultative anaerobic, gram-negative, non-spore-forming rod-shaped bacteria that ferment lactose with gas and acid formation within 48 hours at 35°C. Procedures to detect, enumerate, and presumptively identify coliforms are used in testing foods and dairy products. One method for performing the presumptive test for coliforms … Read moreViolet Red Bile Agar (VRBA)
Levinthal’s Medium The genus Haemophilus includes a number of species that cause a wide variety of infections but share a common morphology and a requirement for blood-derived factors during growth that has given the genus its name. The Haemophilus genus represents a large group of gram-negative rods that grow on agar containing blood. The blood … Read moreLevinthal’s Medium
Lysine Iron Agar (LIA) Lysine iron agar (LIA) is a differential medium used to test organisms for the ability to deaminate lysine or decarboxylate lysine. Lysine deamination is an aerobic process which occurs on the slant of the media. Lysine decarboxylation is an anaerobic process which occurs in the butt of the media. Edwards and Fife designed LIA in 1961 to presumptively identify Salmonella species, including lactose fermenting Salmonella … Read moreLysine Iron Agar (LIA)
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 higher isolation rate for Campylobacter while using the charcoal selective medium. Composition of Charcoal Selective Medium Ingredients Gm/L Beef extract 10.0g Gelatin Peptone 10.0g Sodium Chloride … Read moreCharcoal Selective Medium
Heart Infusion Agar Fastidious organisms having exacting nutritional requirement can be cultivated on infusion media. Meat infusions were included in the first media used for the cultivation of bacteria. Huntoon prepared a medium using fresh beef heart and peptone which became known as Heart Infusion Agar. He demonstrated it could be used to support the … Read moreHeart Infusion Agar
Egg Yolk Agar Egg Yolk Agar, modified is based on the original formula for Egg Yolk Agar developed by McClung and Toabe for the isolation and differentiation of organisms based on Lecithinase and lipase production and proteolytic activity. Image Source: Noura El-Ahmady El-Naggar, DOI: 10.5897/AJMR11.346 Composition of Egg Yolk Agar Ingredients Gms/litre Casein enzymic hydrolysate 15.000 … Read moreEgg Yolk Agar
CHROMagar (Rambach Agar) The first chromogenic culture medium for detection of E. coli was invented and patented by Dr. A. Rambach in 1979. This technology is color-based differentiation method. It is based on soluble colorless molecules (called chromogens), composed of a substrate (targeting a specific enzymatic activity) and a chromophore. When the target organism’s enzyme … Read moreCHROMagar (Rambach Agar)
Endo Agar Endo Agar was developed by Endo to differentiate gram-negative bacteria on the basis of lactose fermentation while inhibiting gram-positive bacteria. Inhibition of the later was achieved without the use of bile salts as was traditionally used. Endo was successful in inhibiting gram-positive bacteria on his medium by the incorporation of sodium sulfite and … Read moreEndo Agar