Microbiology Notes By Sagar Aryal
Introduction Thayer-Martin Agar was developed in 1964 for the isolation of N. gonorrhoeae and N. meningitidis. A further modification of these early formulations was developed to improve the isolation of pathogenic Neisseria sp. from specimens, which contained large amounts of mixed microbial flora. Martin-Lewis Agar is the formulation made after modification which contains an increased … Read moreMartin Lewis Agar
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 … Read moreModified Thayer Martin Agar
Peptone Water Peptone water is formulated as per Shread, Donovan, and Lee. It is a broth medium used for the growth of the organism and a base for determining carbohydrate fermentation patterns of non-fastidious organisms. In addition, it is also used for the detection of indole production by the organism. Composition Ingredients Gms / L … Read morePeptone Water
Introduction MacConkey Sorbitol Agar is based on the formulation described by Rappaport and Henigh. It is selective and differential media for the detection of sorbitol-nonfermenting Escherichia coli serotype O157:H7 associated with hemorrhagic colitis. E. coli serotype O157:H7 is a human pathogen associated with hemorrhagic colitis that results from the action of a Shiga-like toxin (SLT). … Read moreSorbitol MacConkey Agar
Peptone Yeast Extract Glucose Broth Peptone Yeast Extract Broth Based Media are enriched nonselective media that are supplemented with hemin and vitamin K to facilitate the recovery of the more fastidious organisms such as Prevotella spp, Porphyromonas spp, and the Bacteroides fragilis group. With the addition of a specific biochemical, the Peptone Yeast Extract Broth Based Media are used to determine … Read morePeptone Yeast Extract Glucose Broth
Streptococcus Selective Agar Roantree et al introduced a medium for isolation of group A beta-hemolytic streptococci. The medium-enriched with yeast nucleic acid and maltose promoted increased colony size and enhanced clarity and sharpness of hemolytic zones produced by these organisms. Streptococcus Selective Agar is a selective medium recommended for use in the primary isolation of … Read moreStreptococcus Selective Agar
Lactobacilli MRS Broth MRS Broth was developed by deMan, et al., to provide luxuriant growth of lactobacilli isolated from oral, fecal, and other specimen sources. Lactobacilli MRS Broth is an improved medium for lactobacilli, it supports good growth and is particularly useful for a number of fastidious strains which grow poorly on other general media. … Read moreLactobacilli MRS Broth
Cystine Tryptic Agar Cystine tryptic agar (CTA), also known as cystine trypticase agar, was developed by Vera as a semi-solid growth medium used for the identification and maintenance of microorganisms for extended periods when stored at appropriate temperatures. It is used for the detection of bacterial motility and, with added carbohydrate, it contributes to fermentation … Read moreCystine Tryptic Agar
Cystine Glucose Blood Agar Cystine Glucose Blood Agar is known as Cystine Heart Agar. Francis developed blood-dextrose-cystine agar after determining F. tularensis would only grow on an artificial medium supplemented with sulfhydryl compounds (i.e., cystine). F. tularensis is a fastidious organism and requires cysteine for best growth. To recognize the lifetime achievements of Francis in understanding … Read moreCystine Glucose Blood Agar
Plate Count Agar (PCA) Plate count agar (PCA) is a bacteriological substrate used for determination of the total number of live, aerobic bacteria in a sample. It is not a selective medium. The amount of bacteria is expressed as colony forming units per gram (CFU/g), in solid samples and per ml (CFU/ml) in liquid samples. … Read morePlate Count Agar (PCA)