Online microbiology and biology related notes by SAGAR ARYAL
Hektoen Enteric Agar Hektoen Enteric Agar is a selective and differential medium designed to isolate and differentiate members of the species Salmonella and Shigella from other Enterobacteriaceae. The medium was introduced in 1968 by Sylvia King and William I. Metzger. They formulated HE Agar medium while working at the Hektoen Institute in Chicago, to increase … Read moreHektoen Enteric Agar
Eosin Methylene Blue (EMB) Agar Eosin Methylene Blue (EMB) agar is a differential microbiological medium, which slightly inhibits the growth of Gram-positive bacteria and provides a color indicator distinguishing between organisms that ferment lactose (e.g., E. coli) and those that do not (e.g., Salmonella, Shigella). EMB agar was originally devised by Holt-Harris and Teague and further modified by Levine. It is thus … Read moreEosin Methylene Blue (EMB) Agar
Deoxycholate Citrate Agar (DCA) Deoxycholate Citrate Agar is a modification of Leifson formula and is recommended for the isolation of Salmonella and Shigella spp. This medium is similar to deoxycholate agar in comparison but is moderately more selective for enteric pathogens owing to increased concentrations of both citrate and deoxycholate salts. Sodium deoxycholate at pH … Read moreDeoxycholate Citrate Agar (DCA)
Chocolate Agar Chocolate agar is essentially the same as blood agar except that during preparation the red blood cells are lysed when added to molten agar base. As a result, the cell lysis releases intracellular nutrients such as hemoglobin, hemin (“X” factor), and the coenzyme nicotinamide adenine dinucleotide (NAD or “V” factor) into the agar … Read moreChocolate Agar
Czapek’s Agar (CZA) Czapek medium, also called Czapek’s agar (CZA) or Czapek-Dox medium, is a growth medium for propagating fungi and other organisms in a laboratory. It is recommended for use in qualitative procedures for the cultivation of saprophytic fungi, soil bacteria, and other microorganisms. The medium was originally developed by Czapek in 1902 for the cultivation of saprophytic fungi. Czapek-Dox Agar is … Read moreCzapek’s Agar (CZA)
Ashdown’s Agar Ashdown’s medium is a selective culture medium for the isolation and characterization of Burkholderia pseudomallei (the bacterium that causes melioidosis). Ashdown’s medium was first described by LR Ashdown in 1979. Composition of Ashdown’s Agar Ingredients Gram/Litre Tryptone soya broth 10 g Agar 15 g Glycerol 40 ml Gentamicin 4 mg Crystal violet 0.1% 5 ml Neutral Red 1% … Read moreAshdown’s Agar
Campylobacter Blood Agar (CVA) Campylobacter Blood Agar (CVA) is a selective medium used for the primary isolation of Campylobacter jejuni from stool specimens. Dekeyser et al. reported the isolation of Campylobacter jejuni from the feces of patients with diarrhea and acute gastroenteritis by using a filtration technique and a selective medium with antimicrobials to suppress the normal … Read moreCampylobacter Blood Agar (CVA)
Columbia Agar with 5% Sheep Blood Columbia Agar with 5% Sheep blood is highly nutritious general purpose medium for the isolation and cultivation of the non-fastidious and fastidious microorganisms from various clinical specimens and non-clinical specimens of public health importance. Columbia Blood Agar was first described in 1966 by Ellner et al who incorporated animal … Read moreColumbia Agar with 5% Sheep Blood
Buffered Charcoal Yeast Extract (BCYE) Feeley et al in 1978 developed a medium to isolate Legionella species which was later modified by substituting yeast extract for casein hydrolysate and beef extract, and replacing starch with activated charcoal and named it as Charcoal Yeast Extract (CYE) Agar. A further modification was made by Pasculle et al in … Read moreBuffered Charcoal Yeast Extract (BCYE)
Bismuth Sulphite Agar (BSA) The Salmonellae constitute the most taxonomically complex group of bacteria among Enterobacteriaceae. Human Salmonella infections are most commonly caused by ingestion of food, water or milk contaminated by human or animal excreta. Humans are the only reservoirs of S. Typhi. Four clinical types of Salmonella infections may be distinguished namely gastroenteritis, … Read moreBismuth Sulphite Agar (BSA)