Lab Exam 1 Flashcards
ASM (Acidified Sodium Chlorite Method)
Selective? Yes, for the isolation of foodborne pathogens like E. coli O157:H7 and Salmonella.
Differential? Yes, for detecting acid-tolerant bacteria based on their ability to ferment lactose.
Appearance of Results: Differential. Acid-producing colonies will appear pink or red, while non-acid producers will appear colorless.
Groups/Organisms Indicated By Results: It is used to isolate and differentiate acid-tolerant bacteria, especially in food microbiology.
Mueller Hinton Agar
Selective? No
Differential? No
Appearance of Results: Uniform and colorless or pale.
Groups/Organisms Indicated By Results: Used for antibiotic susceptibility testing and supports the growth of a wide range of bacterial species.
Component: D-alanine
Selective? No, it is not a selective component.
Differential? No, it is not a differential component.
Appearance of Results: N/A (It’s a molecule used as a building block in peptidoglycan).
Groups/Organisms Indicated By Results: D-alanine is a component of the peptidoglycan layer in bacterial cell walls, contributing to cell wall structure and integrity.
Anti-fungal
Selective? Yes, if used in a fungal culture medium, it can selectively inhibit the growth of bacteria.
Differential? No, it is not a differential component.
Appearance of Results: N/A (It’s an antimicrobial agent).
Groups/Organisms Indicated By Results: Anti-fungal agents are used to inhibit or kill fungi in culture media, allowing for the selective growth of fungi.
TYME (Tryptone Yeast Extract Malt Extract Agar)
Selective? No, it is not typically used as a selective medium.
Differential? No, it is not typically used as a differential medium.
Appearance of Results: N/A (It’s a general-purpose medium).
Groups/Organisms Indicated By Results: TYME agar is a rich, non-selective medium used for the general cultivation of a wide range of microorganisms, including bacteria and fungi.
Tryptone Soy Broth (TSB)
Selective? No, it is not typically used as a selective medium.
Differential? No, it is not typically used as a differential medium.
Appearance of Results: N/A (It’s a general-purpose broth).
Groups/Organisms Indicated By Results: TSB is a versatile, non-selective liquid medium used for the general cultivation and growth of a wide range of microorganisms, including bacteria and fungi. It’s often used for microbial culture, propagation, and maintenance.
Indole
Selective? No, it is not a selective component.
Differential? No, it is not a differential component.
Appearance of Results: N/A (It’s a chemical compound).
Groups/Organisms Indicated By Results: Indole is a chemical compound that can be produced by some bacteria as a metabolic byproduct. The indole test is used to detect the ability of bacteria to produce indole from tryptophan. Positive results for indole production are indicated by a pink to red color after the addition of Kovac’s reagent. It is often used in the identification of Enterobacteriaceae, such as E. coli.
Motility Agar Tube
Motility Agar Tube
Selective? No, it is not typically used as a selective medium.
Differential? No, it is not typically used as a differential medium.
Appearance of Results: N/A (It’s a specialized medium).
Groups/Organisms Indicated By Results: Motility Agar is used to determine the motility of bacteria. It contains agar to solidify the medium but does not contain specific selective or differential components. The appearance of results in Motility Agar tubes involves the growth pattern of bacteria. Motile bacteria will spread out from the point of inoculation, creating a diffuse, cloudy appearance throughout the tube, while non-motile bacteria will grow only along the line of inoculation, leading to a confined, limited growth pattern. This medium is commonly used in microbiology to differentiate between motile and non-motile bacterial species.
Tryptone Soy Agar (TSA)
Selective? No, it is not typically used as a selective medium.
Differential? No, it is not typically used as a differential medium.
Appearance of Results: N/A (It’s a general-purpose agar medium).
Groups/Organisms Indicated By Results: TSA is a commonly used, non-selective solid medium for the general cultivation and growth of a wide range of microorganisms, including bacteria and fungi. It supports the growth of most organisms without favoring specific groups or organisms. TSA is frequently employed for microbial culture, isolation, and enumeration in microbiology laboratories.
Urea Broth
Selective? No, it is not typically used as a selective medium.
Differential? Yes, it is differential.
Appearance of Results: A positive result shows a color change to pink or magenta, indicating the presence of urease activity. A negative result remains yellow.
Groups/Organisms Indicated By Results: Urea Broth is used to differentiate bacteria based on their ability to hydrolyze urea. Organisms capable of urease production will hydrolyze urea, resulting in an alkaline pH shift and a change in color to pink or magenta.
Catalase Test
Selective? No, it is not a selective component.
Differential? Yes, it is differential.
Appearance of Results: Bubbling or effervescence indicates a positive result, indicating the presence of catalase activity. No bubbling is a negative result.
Groups/Organisms Indicated By Results: The catalase test is used to distinguish between organisms that produce the enzyme catalase (e.g., many bacteria) and those that do not (e.g., Streptococcus species). Catalase-positive organisms produce bubbles when hydrogen peroxide is added.
BHI Slant (Brain Heart Infusion Agar Slant)
Selective? No, it is not typically used as a selective medium.
Differential? No, it is not typically used as a differential medium.
Appearance of Results: N/A (It’s a general-purpose agar slant).
Groups/Organisms Indicated By Results: BHI Slant is a non-selective medium used for the general cultivation and maintenance of a wide range of microorganisms, including fastidious bacteria. It provides a rich nutrient source for bacterial growth.
PPA Test (Phenylalanine Deaminase Test)
Selective? No, it is not a selective test.
Differential? Yes, it is differential.
Appearance of Results: A positive result shows a green color after the addition of ferric chloride reagent, indicating the presence of phenylalanine deaminase activity. A negative result remains yellow.
Groups/Organisms Indicated By Results: The PPA test is used to identify organisms capable of deaminating phenylalanine to phenylpyruvic acid. Positive results are typically seen in organisms like Proteus species.
Oxygen Soft Agar
Selective? No, it is not typically used as a selective medium.
Differential? No, it is not typically used as a differential medium.
Appearance of Results: N/A (It’s a specialized medium for determining oxygen requirements).
Groups/Organisms Indicated By Results: Oxygen Soft Agar is used to determine the oxygen requirements of bacteria. Bacteria that require oxygen will grow only on the surface, while those that are facultative anaerobes may grow throughout the tube.
Starch Agar
Selective? No,
Differential? Yes, it is differential.
Appearance of Results: A clear zone around the bacterial growth amylase
Amylase production by bacteria. Amylase-positive bacteria hydrolyze starch, resulting in a clear zone around their growth.
The plate is black and a positive test looks wicked orange and shit
